Here are the basics of keeping a Freshwater Aquarium;
By Carl Strohmeyer-PAMR 35+ years experience
Please also read the companion article to this one: Freshwater Aquarium Set Up Suggestions
Start with as large an aquarium as you can afford (even for bettas).
The very BASIC principle is to have 1 inch of NARROW bodied fish per WELL FILTERED actual gallon of water is a starting point, but not very accurate. This also only applies to a standard rectangular aquarium.
Goldfish have a higher impact on the bio load with more body mass per inch (being grazers they ounce per ounce produce more waste), so I would triple this with them, in fact for long term goldfish health, one goldfish per 8-10 gallons is best (One goldfish per 30 liters).
Obviously longer fish need more tank width and length. I would decrease the amount of fish proportional to the gallons in a tall aquarium or hexagon aquarium.
Remember, many fish purchased can grow much larger than your original purchase size (ex: goldfish), so keep this in mind too.
* To figure your tank size get your tank length, height, and width in inches then apply this formula (multiple all dimensions):
L x H x W = X; Then divide X by 231
This gives you exact gallons of the tank. In round tanks or unusual shapes you will have to extrapolate.
To convert gallons to liters multiply by 3.785
(Ex. a 20 gallon tank = 75 liters).
What is much more important in determining how many fish you should add to your aquarium are these factors:
- The amount of surface area relative to the gallons of water the aquarium holds. I have observed many tall narrow aquariums over the years of my maintenance service where the filtration and other factors were equal to comparable sized and stocked rectangular aquariums, that general fish health and longevity were lower.
- Type of fish, such as fish that naturally produce more waste (partly
due to the type of food they eat) such as goldfish which are grazers with less efficient digestive systems. As noted earlier with goldfish one fish per 8+ gallons is suggested.
Also a fish, such as an Arowana, that stays primarily on the surface will need a disproportionately large aquarium (I recommend 200 + gallons for just one Arowana).
- Body mass per inch/centimeter. The actual weight of a fish has more bearing on the aquariums capacity than the length. Many high capacity bio-filters such as the TMC Fluidized Sand Filter actually are rated by weight of the bio load with the #1500 model rated for 30 lbs. of fish or other inhabitants.
For instance, you cannot compare a heavy bodied cichlid for instance to a narrow bodied tetra of similar length. AS well a tiny Bamboo Shrimp with very little weight is going to have very minimal impact on the bio load and thus the capacity of the aquarium.
Product Resource: TMC FSB Premium Aquarium Bio Filters
- Filtration, a properly filtered aquarium (good bio filtration, good mechanical filtration, and good circulation) with multiple filters is important. Good bio filtration (such as Sponge or Fluidized Sand Filters) with well maintained filters can go a long way in allowing an otherwise small aquarium to hold more fish or a large tank maintain a healthy "Monster Fish Tank".
- Maintenance schedule that includes regular efficient water changes.
- Well maintained water chemistry, including GH (mineral ions), KH and Redox not just low ammonia, nitrites, and nitrates. In other words, a Redox that moves up in down with large changes in ORP likely indicates an aquarium with too high a bio-load.
Redox ORP Meter
- New or experienced aquarist; a new aquarist needs to start with a much less crowded aquarium.
- After proper feeding, good cleaning routines (20% water changes with a gravel vacuum once per week or two), proper feeding routines, good filtrations; If after all these are checked off and you still have nitrates that struggle to stay below 40-50 ppm, you probably have an over stocked aquarium (especially if there are live plants!). Also a kH and pH that starts out at proper levels, but then drops quickly after water changes and/or addition of stabilizing chemicals/buffers can indicate over stocking (as well as other problems such as mulm buildup).
Find a good Aquarium or Pet Store. Look at their fish and see how well they are taken care.
If the store has central filtering system, be careful, as if one fish is sick in one aquarium it can be spread to all aquariums.
Never buy fish from an aquarium with sick fish.
In the aquarium stores I set up I never placed more than two aquariums on one system so if there was a disease outbreak it was easier to isolate.
We also had UV Sterilizers on ALL systems.
This is not to say that if you find a good dealer with a central system to not buy from them, just keep in mind if you see a tank of sick fish, the whole store may have been exposed.
Many large retailers have central systems for their convenience, NOT YOURS.
Finally as to tank size;
this is often a controversial subject among aquarist, especially well intentioned advanced aquarists. The bigger an aquarium you can afford, maintain and have space for, the better for many good reasons, BUT I have kept MANY aquariums under a variety of conditions and monitored them in controlled experiments and often a small aquarium can work for what many might consider over crowded conditions, provided excellent filtration, cleaning maintenance, circulation, feeding procedures (and quality food), chemistry, etc.
For example, I can state categorically that a 10 gallon aquarium with (2) 2 inch goldfish that is well maintained with a hang on the back (power) and a sponge filter will have vastly better water parameters than a 20 gallon with the same goldfish that is poorly maintained with a corner bubbler filter.
Product Examples include:
*Rena Smart Filter &
*ATI Premium Aquarium Sponge Filters
Here is an Aquarium Answers Post Dealing with this subject in a more factual way:
Aquarium Size and Fish Stunting
For the average aquarium I recommend 2-3” of #3 or pea sized gravel. This allows for less build up of hydrogen sulfide producing anaerobic bacteria. The down side to larger gravel is that it will allow for more waste particle or eaten food to accumulate. With proper maintenance though, waste accumulation should not be a major problem.
Sand is good for heavily planted aquariums, as it provides a better anchor for the roots and even more important sand traps nutrients and symbiotic bacteria needed by plant roots.
If used for live plants, I recommend about ½” #00 or #1 sand followed by 2-1/2” of medium (#3) gravel, with substrates such as SeaChem Flourite or Eco Complete mixed in around plant roots. These two products can be substituted totally for gravel or sand (Although that can get pricey).
Product Resource: SeaChem Flourite; Planted Aquarium Substrate
If your aquarium is going to be only lightly or moderately planted, I recommend sand only in the area around the plant roots and #3 size gravel elsewhere (otherwise you may develop Hydrogen Sulfide producing anaerobic bacteria).
Consider mixing different types of natural or colored gravels to achieve a look you like.
For hospital, breeding, or heavily populated temporary holding tanks; no sand or gravel is best. This allows for less waste build up, less possibility of waste matter or substrate absorbing medication in a hospital tank, and less rotting organic sludge in a holding tank.
For a little more info about substrate, please read this article:
Aquarium Gravel, Substrates; Which size?
I always recommend two filters minimum per aquarium for redundancy (in case one filter fails) and for improved biological (nitrifying) filtration.
Air Pumps and power heads/circulation pumps can also be added to maintain good circulation & aeration, as well as to move water to existing filters.
Combined Suggested Aquarium Turnover Rates (per hours):
- 5 times for an average non-planted freshwater aquarium
- 2-5 times for an average planted freshwater aquarium
- 2-3 times Betta or Fish Fry Grow-Out aquariums
- 6-10 times for high bio load aquarium such as a "Monster Fish" aquarium
The size of your filters are also determined by other filters present in your aquarium as well as your aquarium "bio load" (number and size of fish and other inhabitants kept in an aquarium).
As an example in a 50 gallon aquarium with an average bio load of 40-45 small Platties; if you prefer a canister filter, a Rena Filstar XPS would work fine by itself (although I still recommend another filter for redundancy), however this same filter would work fine in a 75 gallon aquarium assuming a light bio load or if another filter is present to assume part of the load such as a Hydro Sponge 3 Filter
*Rena Filstar XPS Filter
*Hydro Sponge #3 Aquarium Filter from AAP
A Sponge Filter is an excellent compliment to most filters as the sponge filter can extend the tank size capacity of most filters they are used in conjunction with.
What is not always recognized by many (especially due of the cut and paste nature of the Internet), IS the fact (as per extensive controlled tests) that a well designed Sponge Filter can be the primary filter in ANY SIZE aquarium.
These tests showed a sponge filter exceeding all equivalent sized Power Filters (such as a Hydro Sponge #5 exceeding an AquaClear 110 for a 75 gallon aquarium for aerobic bio filtration).
Only a Fluidized Filter exceeds Sponge Filter efficiency when compared "apples to apples" models.
*Hydro Sponge #5 Aquarium Filter
*TMC Premium Fluidized Bio Filters
This article is a MUST READ:
Sponge Filtration; Facts & Information
Taking the aerobic bio filtration a step further, a Fluidized Sand Bed Filter can actually outperform most any high priced canister filter such as the Fluval FX5 and a Fluidized Sand Bed Filter and/or Premium Sponge Filter make a much less complicated alternative to messy canister filters (especially for those who find canister filters simply a pain to mess with).
Reference: Aquarium Filtration: Fluidized Filters
For a small aquarium, a combination of a "Hang On the Back" (HOB) power filter (such as the SunSun Economy HOB Filter) and a Sponge Filter.
Or a sponge filter and an internal power filter (such as the SunSun Internal Power Filters) as another potential combination.
You want to make sure and rinse your sponge or cartridge out in used aquarium water to maintain your beneficial bacteria for bio filtration. Another note about the HOB filter is that they are far more efficient as bio filters if used with a sponge pre filter such a filter max.
The SunSun 702 series is more than an economy filter in that it is similar to more pricey HOB filters (such as the Tetra EX) with its motor design that pulls water in rather than one that pushes water out which makes priming easier and also does not have the tendency to get carbon or other particulates stuck in the impeller.
*SunSun Economy HOB Aquarium Power Filter
*Internal Power Filters
For a mid size (or really any size) aquarium, you might consider a premium HOB Filter such as the Rena Smart Filter or Rena SuperClean Filter (for best value) as well as the before mentioned Sponge filter for added redundancy.
There are Four Types of Filtration,
Other HOB filters worthy of note are the Aqua Clear, Whisper, and Tetra EX series filters (which also have a motor that draws water in rather than pushes it out).
Product Resource: Rena Smart & SuperClean Filters
For larger aquariums, a combination of a Fluidized and/or Canister Filter and an Internal Filter for cross circulation.
As for canister filters, I recommend Rena Filstar, Eheim, SunSun. While popular I do NOT recommend Fluvals as they have poor head pressure, high flow by rates and an un-reliable impeller based on my statistics which are based on using literally 100s.
Other filters of note include the wet/dry.
Product Resource: SunSun Canister Aquarium Filters
For Filter (& water pump) circulation, I recommend a minimum of a combined flow rate that turns over an aquarium a minimum of 5-6 times per hour, however 8-10 times would be better (although part of this can be simple circulation pumps), especially for fish such as goldfish.
As an example, I would recommend HOB (hang on the back power filter) of 150 gph plus a sponge filter that is moving 200 gph for a combined total of 350 gph for a 50 gallon aquarium (this is a turnover rate of 7 times per hour).
Adding circulation pumps such as a Seio Propeller Pump or an air-stone can also add to circulation, however I still recommend at least 5-6 times per hour through a filter and the remainder of circulation via simple circulation pumps, air stones, or similar.
Product Resource: Seio Aquarium Propeller Water Pump
Care of these Filter Types
*Biological; the removal of nitrogenous waste (ammonia, etc.), which is the most important type.
Care: Rinse with de-chlorinated water (or used aquarium water) every two to six weeks depending upon flow through media. Change only when media can no longer be rinsed reasonably clean.
A common mistake with basic aquarium set ups this simple single cartridge only filters (especially the simple single cartridge filter kits sold at Walmart, PetsMart, etc.), is to throw way the cartridge during routine maintenance. Unfortunately if this is the sole filter, every time the filter cartridge is thrown out, the majority of the essential Aerobic Autotrophic nitrifying bacteria is thrown away too.
Better is to have second cartridge seeding for at least two weeks near the filter intake or exhaust and then to use this as a replacement.
MUCH BETTER is to have either a Sponge Pre-Filter on your filter intake which will preserve this beneficial bacteria OR to have a second (or even the primary) filter that is a "stand alone" Sponge Filter.
With either of these sponge filters, rinsing with de-chlorinated water will preserve your important bio filtration colonies and constant & dangerous ammonia/nitrite spikes will be a thing of the past!
*ATI Sponge Filters &
*ATI Filter Max Sponge Pre-Filters
*Mechanical; the removal of larger debris (organic and inorganic) before it can go through the nitrogen cycle (organic) by means of filter fiber, sponges or other similar media.
Care: Change or rinse every two to six weeks depending upon condition of filter media (how fast it "clogs, etc.)
*Chemical; The removal of chemical contamination via carbon, zeolite or many other products. This becomes less important in a healthy, established aquarium. Carbon is often overused in healthy well established aquariums. If I even use carbon, I will generally use only one teaspoon per 5-10 gallons. I do add more and change it more often in tanks treated with medication or a new aquarium.
Carbon is often not 100% necessary in established aquariums especially tanks with regular water changes and plants. I generally only use carbon to remove chemicals after treatment then remove the carbon. You can also leave old carbon to become a nitrifying bacterial colony. This point about carbon also lends credibility to Sponge Filters which are often considered poor filters due to the fact they provide no chemical filtration, this is based on poor information as to the need for carbon filtration.
Further Reference: Use of Carbon in Aquariums, Ponds
Care: Change the carbon every 4-6 weeks depending upon water parameters carbon is being used to improve. Carbon may need to be changed or "refreshed" after each treatment with medications (not water conditioners)
*Germicidal; The use of UVC or ozone to kill disease pathogens and control the Redox potential (though ozone generators do NOT improve Redox Balance).
Care: Change your UV Bulb every six months.
*Tropic Marine Center Ozone Generators
*Use of UV Sterilization for Aquariums
*UV Replacement Bulbs
If an air pump is used for added circulation or to power a filter such as a Sponge Filter, placement of this pump can make quite a difference in its longevity.
Placement above the water level, even with the most inexpensive air pumps DOES make a difference in the life span of the pump.
I have had many a 'cheap' pump last 4-5 years when placed above the water level and 'better' air pumps last less than a year when placed under the aquarium.
If not possible adding a check valve is a must, as well looping the tubing about three times at the top of the tank can help.
Without taking these measures, a pump below the water level can also back siphon water during a power failure or simply if the pumps fails.
Additional control of air flow can be done with airline control valves and Ts. Use of both T and valves can allow for bleeding off of air to prevent damage to the air pump by just using a valve to lower air volume.
Sources for Air Pumps and air control parts:
*Million Air Aquarium Pumps
*Fusion Premium Air Pumps & Air Control Parts
HEATERS & WARM WEATHER COOLING:
Most tropical fish do well at a temperature between 76 and 80 degrees Fahrenheit. (Discus prefer warmer).
Goldfish do not need a heater.
I recommend 25 watts for every 10 degrees of ambient temperature you need to raise your aquarium temperature.
Example: If your home is 68 degrees and you have a 40 gallon aquarium, to reach a temperature of 78 degrees you would need a 100 watt heater.
Also remember that bettas are still basically tropical fish too, so if they are kept in a bowl try and keep them in a warm area of your house, preferably above 70 F.
A light does not pass for a heater, you cannot leave your light on 24/7 (an exception would be an Infrared reptile lamp, which are great for bettas).
If your temperature fluctuates between night and day, even though you have the correct wattage heater, you may have an “Automatic” heater vs. a “Thermostatic” heater.
Usually the cheaper clip on the back are automatic heaters; these respond to a setting (two contacts that are tightened for more heat), not by temperature. These heaters generally turn on and off at the same rate whether it is summer or winter (which is why they need seasonal adjustments).
The best heater will have a separate temperature probe such as most Digital Titanium heaters.
For some examples of Thermostatic Heater, including Titanium, please see:
For more about aquarium heaters, please see this more in depth article:
Aquarium Heaters; Information & Review
Cooling; Sometimes cooling a tank in the warm summer months can be an issue, and most freshwater aquarists cannot afford an expensive chiller (which can cost $500 +). In many applications, even a an air conditioner is not a viable option.
A few suggestions include floating frozen 2 liter plastic pop bottles in the aquarium and/or the use of a wet towel draped over the tank with a fan aimed at this towel along with an open lid if viable depending upon fish kept (not viable for Arowanas for instance since they will jump out), this works similar to human perspiration or an evaporative cooler (do not cover lights or anything that would still trap the heat trying to escape via evaporation).
The wet towel/fan method is more efficient for larger aquariums and tends to have less temperature swings, however sometime the frozen bottle method is needed for quicker lowering of temperature; as well both methods can be combined.
In fact the wet towel method was provided by an old timer in the hobby quite some time ago after I mentioned I was using fans with an open top and he stated that the use of a wet towel greatly increases the efficiency of the fan, especially if it is not viable to leave the top open. In fact, if it were an either or situation; wet towel or fan only, the wet towel is more effective.
I often had clients leave a wet towel & fan on their tank before leaving for work, then add a frozen bottle when they come home.
Other options can simply be to add a small room air conditioner and set it at a high setting of 78 F. This can often be cheaper than both the purchase and operating cost of an aquarium chiller in my experience.
If tap water is used it will have to be treated to remove chlorine or even chloramines and heavy metals.
Products such as "Weco DeChlor" for basic chlorine removal and "Jungle Start Right" which can remove chlorine as well as some metals and also break the ammonia/ chlorine bond in chloramines and remove the chlorine but both leave the ammonia IF present.
“SeaChem Prime”, Amquel Plus, Ammo Lock or similar products are good to use in municipalities where chloramines are used in tap water.
SeaChem Prime or Amquel Plus are excellent first choice products to use when ammonia and nitrite levels are an issues, as these do not interfere with the cycling process as other products can when used properly.
These can help with natural slime coat generation and are also temporary Redox Reducers which can aid in oxidative stress.
More about Redox: Aquarium Redox
*Jungle Start Right
RO (Reverse Osmosis) water can be used IF minor elements and electrolytes are added. NEVER use straight RO water or even worse, distilled water.
For MUCH more information about tap water, please read this article:
“What should I know about Tap Water for my Aquarium? From Chlorine and Chloramines to Phosphates”
Product Resource: TMC New Technology RO Aquarium Filter Systems
Salt is also commonly added to freshwater aquariums as a disease preventative, slime coat stimulant, or simply due to possible requirements by certain freshwater fish such as Livebearers or African Cichlids to have salt present the water.
For more about the use of salt in freshwater aquariums, as the use there of often is recommended as a cure all for everything or totally panned, neither of which view is correct based on the science behind correct use:
Use of Salt in Freshwater Aquariums
Generally 1 tablespoon per 5 gallons (35 liters) of water for a community tank is what works best.
However this amount may be increased to double this for many livebearers such as mollies (please note that mollies need much more than salt, such as calcium and other elements).
I recommend reading this article for more information:
“Mollies in Aquariums; Including Importance of Correct Water Chemistry”.
It should also be noted that some catfish (such as Cory Cats) are very sensitive to salt and care should be given in use of salt when these fish are present.
Salts (and not just NaCl) do not evaporate and only small amounts are depleted by normal life processes of aquarium inhabitants, so salt should only be added back during water changes and ONLY for the amount of water removed (changed) to prevent accumulation.
Here is one source for an advanced salt that includes other essential elements:
SeaChem Freshwater Aquarium Salt
AQUARIUM WATER TOP OFF FOR EVAPORATION (including ATO):
Evaporation of aquarium water is a constant issue for any aquarium, but much more so open top aquariums and/or aquariums with sumps.
Most often, the use of tap/well water is perfectly fine and even chlorine is not an issue with very small top offs in closed aquariums (not so much chloramines).
The bigger problems arise in aquariums with large evaporation, especially Amazon or similar bio-topes or planted aquariums where build up of certain minerals could be problematic with well/tap water use. Generally RO or DI water (not home water softener water) is excellent for this use in these more specific systems. However with many fish such as livebearers, East African Cichlids , and similar, I would not be concerned.
Reference why not to use home/office water softener in aquarium:
Softened Water; Home/Office Water Softeners Use
Products such as SeaChem Replenish or AAP Regular Wonder Shells are recommended in the reservoir water used for toping off. For an AAP Wonder Shell, just 1/4 dose per water volume is all that is needed and even then, my experience has shown these dissolve very slowly when an ATO system is utilized.
As for Automatic Top Off Systems (ATO), there are many ways to do this from simple floats (like used in toilets reservoirs), the Hydor Smart Level and similar electronic ATO systems, or simple gravity fed ATO reservoirs that use a simple air line valve to control input of water placed above the aquarium,, often hidden and out of the way.
In the average aquarium, I prefer the later DIY reservoir, as I have rarely had issues other than keeping the valve from clogging from deposits (usually this is a problem with tap/well water). While I like many Hydor products, I cannot recommend their Smart Level ATO due to too many failures reported by persons I trust, not to mention the high price.
Your aquarium will not be at peak biological filtration for 6 weeks (or more).
To start your biological filtration, there are many cycling products available, many such as “Cycle” by Hagen are made with Heterotrophic Bacteria instead of the proper Autotrophic nitrifying bacteria. My success with these products is mixed at best.
A better cycling product would be SeaChem Stability which is a blend of synergistic blend of aerobic (including encapsulated oxygen) and facultative bacteria.
Even then this product should not be depended upon as the sole means of nitrogen cycling, ONLY AS AN AID!
Product Resource: SeaChem Stability
I prefer to add gravel and/or used filter sponge or cartridge from another well established aquarium.
This method of adding seasoned filter media is much faster in establishing a bio filter (you still have to take it slow), and provides all the necessary bacteria.
The only negative is rare possibility of adding disease pathogens to your aquarium, but I have rarely encountered this problem.
We used this method for our Aquarium Maintenance route for years and never lost a fish to Ammonia or nitrite poisoning.
If you add plants (many such as hornwort remove nitrogenous waste directly), you can stock somewhat faster as the plants will remove ammonia too, but also usurp the establishment of nitrifying bacterial colonies.
Another method is fishless cycling include adding fish food to bring your ammonia to about 4-5 ppm or the use of un-scented ammonia where it is added into the aquarium (3-5 drops per gallon pure ammonia) so as to bring your ammonia level to 4-5 ppm. It then takes about 2-6 weeks for the aquarium to cycle.
Cycling is what is referred to as the Nitrogen cycle.
Waste (nitrogenous) from the fish is broken down first from ammonia (NH3, the most toxic) to nitrites (NO2, less toxic) to nitrates (NO3, least toxic- but high amounts can stunt fish growth and lower disease resistance).
At a pH of 6.5, NH3 (ammonia) converts to NH4 (ammonia) which is basically non-toxic to most fish (many ammonia removing chemicals such as Prime utilize a similar ion change, as they do not actually remove ammonia).
If you have plants in your aquarium many will directly consume the ammonia (especially hornwort), thus rendering the NO2 (nitrite) part of the nitrogen cycle null. The danger here is if your pH climbs above 6.5 the ammonia can change to much more toxic NH3 and the aerobic bacteria needed for nitrite consumption will be sparse.
Aquarium cycling is a VERY important topic (more so for a beginner) and I highly recommend reading the FULL article below about The Aquarium Nitrogen Cycle.
This article will go into MUCH greater depth about all aspects of cycling and explain the truths and myths as well:
Aquarium Nitrogen Cycle and Cycling
CHEMISTRY (& TEST KITS):
First, please note that this section is a VERY brief and basic outline of freshwater aquarium chemistry; for any aquarium keeper looking to go beyond just very basic aquarium keeping, please read these articles:
*The above noted Nitrogen Cycle Article
* Aquarium Chemistry
The above article has a basic suggestions section near the end that is worth reading.
* Osmoregulation in Fish; Minerals; Use of RO, Soft Water for Aquarium
Next, it is generally helpful to know your new water source parameters (tap water, etc. used for filling your aquarium). This will help you make what is generally only minor adjustments to your chemistry with buffers and mineral supplements.
Keeping exact GH, KH, & especially pH is for advanced fish keeping and should should not be attempted until an aquarium keeper has a clear understanding of aquarium chemistry as well outlined in the above reference "Aquarium Chemistry" article.
As an example, the use of products such as "pH down" should NEVER be used
Summary of "Numbers" to Maintain:
Very toxic even at low levels, should be kept at or near 0
Here is a source for Ammonia Test Kits: Aquarium Test Kits; Ammonia"
Please see this article for more about lowering ammonia/nitrite and preventing high aquarium ammonia/nitrite:
Aquarium Nitrogen Cycle; High Ammonia/Nitrite Problems
*Nitrates; under 40-50 ppm (lower yet is always better)
Reference this article for information about controlling Nitrates:
Aquarium Nitrate Control
Product Resource: Nitrate Test Kit from AAP
*GH: this is best above 100 ppm for 90% of FW fish and above 200 for over 60%
Product Resource for a GH Test Kit: GH Test Kit from AAP
GH is also the parameter ESSENTIAL positive mineral ions (Cat-ions) are found in, and fish kept in water with inadequate mineral cations can suffer health problems over the long term.
Wonder Shells, SeaChem Replenish, and to some degree Aragonite & crushed coral can help with important mineral cations (although crushed coral does not dissolve at a rapid enough rate to help as well).
Please Reference/Read: Aquarium Chemistry; Depletion of Positive Mineral Ions
Product Resource: Wonder Shells; Unique Version ONLY from American Aquarium
*pH; Stable is most important, but for general community tanks a 6.8-7.8 falls within most fish tolerances as long as there is pH stability since the pH scale is logarithmic and sudden changes can be deadly.
As well, pH depends very much on the fish you are keeping.
Discus prefer under a ph below 7.0, while Mbuna African cichlids prefer above 8.0, but again I want emphasize "stability" over the actual pH "number".
As well KH along with GH are often more important than many aquarium keepers realize (KH affects pH stability). If you manage your KH levels to where they should be, your pH should fall into range. (It will not always be the same, but will be in the proper range when GH and KH are properly managed.)
Please see this article for more on the subject of pH:
Aquarium Chemistry; pH
Product Resource for pH Test Kits: Aquarium Test Kits from AAP
*KH; VERY important for pH stability which is why I this is a more important test than pH in my experience and knowledge of aquarium chemistry.
Sea Chem Buffers and to some degree Aragonite can help maintain a high KH & pH when you desire an aquarium with a higher pH/KH especially where tap or well water is very acidic.
It is noteworthy that Buffers are generally best tested via KH, not pH, otherwise using buffers for exact pH maintenance can result in dangerous pH chasing.
For a lower pH in aquariums where the tap water used is very high (usually 7.8 or above), I have used blends of RO (Reverse Osmosis) water and tap water.
The ratio varies with the tap water pH, KH, & GH and the water conditions I want to achieve.
With advanced Discus aquariums, it can be 100% RO water assuming the water is properly re-mineralized with products such as SeaChem Replenish; RO Water Mineralizer.
Then to maintain these conditions I use peat in my filters.
Product Resource: SeaChem Replenish from AAP
Another method for lowering pH is crushed almond husk or Pillow Moss.
This actually works quite well for this purpose.
ZooMed Frog Moss is actually pillow moss and can be used in aquarium filters for this purpose.
Product Resource: Pillow/Frog Moss
Note that GH does not directly affect pH.
Also note that calcium is also important for fish metabolism and fish health and healing (along with other essential electrolytes/minerals found in "GH").
With the above method of using RO (or DI) water in a blend with tap water and peat, I have still been able to maintain a a low but still healthy KH and GH level.
*Caution; Soft Water Use: water that originates from a home or office water softener that uses sodium (salt) should Never be used in any aquarium.
As well use of so-called Drinking Water or 100% Reverse Osmosis water should only be used by a more advance aquarium keeper that knows how to properly re-mineral this water (for those that know how, the water quality will be top notch).
Please read why the use of Soft Water has dangerous implications for your fish:
Use of Soft Water for Aquarium; Dangers
Suggested Test Kits;
It is always best to have as many different test kits (that apply to a freshwater aquarium) as you can afford.
*Test Strips, although generally not as accurate are still very useful for quick readings that are STILL ACCURATE ENOUGH (provided stored dry) for a beginner or intermediate aquarist to get a very good barometer of aquatic health.
The 5 in 1 Test Strips provide 5 key aquarium parameters including the important yet often missed KH and GH test. Although the ammonia test is missing, the nitrite test is often a good enough parameter for established aquariums (past the cycling process).
As well for ammonia, I MUCH PREFER the SeaChem Ammonia Alert since it tests ONLY for toxic NH3 versus both NH# and non toxic NH4 as with 95% of all other aquarium tests. This product is also quick and easy to read the way it simply sit inside the aquarium.
My bottom line recommendation is the combination of the 5 in 1 & Ammonia Alert for most freshwater aquarium keepers if you were to choose just two tests (BTW, I never recommend the Master Test Kits!)
*5 in 1 Test Strips from AAP
*SeaChem Ammonia Alert
For a more in depth article and explanation about Aquarium Test Kits, please follow this link:
AQUARIUM TEST KITS; what they are used for and their importance.
For the average freshwater aquarium, lighting is not as important a consideration as it is for a planted freshwater aquarium or reef aquarium.
is often a problem in established FW tanks with poor lighting (usually the incorrect spectrum, PAR %).
There is also some evidence (not conclusive) that good lighting aids in Correct Redox which is a water parameter that has an definite effect on fish health.
*Aquarium Algae; Brown Diatom
These same 6400 K high output CFL aquarium lights can also be purchased separately and used in standard incandescent aquarium (or other) light fixtures as pictured to the left.
Another newer yet technology that is easy to adapt to a basic freshwater set up is the T2 Aquarium Light which is available in unique linkable & rotatable fixtures for tanks from 8 to 60 gallon (or larger depending on how many are linked).
The T2 would be my recommendation for freshwater aquarium keepers that want a “step up” in lighting without a high price (the T2 out perform all aquarium lamps including older technology T5 in useful light energy output for energy used except for LED).
Product Reference: Aquarium T2 Lighting
For the highest output of useful light energy, the TMC Colour Plus (excellent to bring out colors) and even more so the GroBeam LED Aquarium light are by far the leaders among all lights (including MOST ALL other LEDs) except maybe Metal Halides, but this may be cost prohibitive to many basic freshwater aquarium keepers.
Product Resource: Aquarium LED Lighting; GroBeams & Colour Plus
Finally, good ole fashioned T8 & T12 aquarium lights such as the Aquarilux by Penn Plax that are available in lengths from 12 to 48 inches are still practical for a basic FW aquarium application.
Coralife, Hagen and Zoomed make comparable aquarium lights, all of which are useful for bringing out the colors of the fish, albeit lacking in lumens per output, PAR, and other lighting benefits (that are still helpful for a fish only aquarium).
I would NOT recommend standard incandescent light bulbs (which are unfortunately still sold in many aquarium supply outlets) and STRONGLY recommend the use of the self ballasted CFL aquarium lights that will fit into these incandescent fixtures.
As well, not all CFL you may see available in hardware stores, Walmart, etc are equal, the vast majority are of under 4500 K and not adequate for aquariums.
Product Resource: Self Ballasted CFL Lights; 6400K.
Cool White lights also are NOT appropriate for aquariums due to poor lumens per watt, incorrect PAR and Kelvin output which can result in growth of Cyanobacteria or Brown Diatom Algae.
Hardware Store/Walmart Grow-Light bulbs can be an inexpensive alternative and have a better PAR than most inexpensive bulbs, however even these have a low lumen per watt output and are not quite the bargain they may seem when this is considered.
Please reference this article for more about Aquarium lighting from basics to advanced (also see the basic freshwater section in the summary near the end):
AQUARIUM LIGHTING; Researched and current information about aquatic lights.