Please note that these suggestions are not intended to be an exhaustive listing of filters, pumps, etc.
Many good filters may be left off, but this does not mean they are of poor quality; as well some poor filters are either intentionally left off or may be noted. We can only make suggestions for the products we are familiar with.
I recommend reading these articles for more about aquarium filtration (more in depth information, facts, reviews):
*Aquarium Filtration; Filters
GENERAL AQUARIUM SET UPS BY SIZE:
5-60 Gallon; Filter/pumps suggestions:
*Premium considerations include the Rena/API Super Clean 20, 30, & 50 Power (HOB) Filters (the #30 for tanks 30-40 gallons and the #55 for tanks 45-60 gallons).
As well as the new AAP/Seachem Tidal Model 55 with its superior bio capacity, construction, & warranty
Other power filters to consider include these excellent economy but well made power filters: SunSun HBL-501 Power Filter (to 25 gallons), SunSun HBL-702 Power Filter (to 45 gallon aquarium), Via Aqua VitaLife M100, Aqua Clear 30, Aqueon 20 (or Aqueon 10 for 10 gallon aquariums), Whisper EX 30 (which is of the same design as the Aqueon).
In place of a HOB filter an internal wet/dry filter might also be considered such as the ReSun BF100 Internal filter. Although these filters take up valuable internal aquarium space, they are superior to many HOB filters in versatility and bio capacity.
*To compliment (or even as the primary filter), a Sponge filter such as the Hydro sponge #1 or #2 for a 10 gallon or a Hydro sponge #2 or #3 for a 20 gallon. For aquariums under 20 gallon I prefer the more gentle vertical circulation via an air pump or they can be purchased via Filter kits with air pumps already included.
For general Aquariums, I really like the combination of a good HOB such as the Via Aqua or Whisper that have low flow by and fine mechanical filtration (the Via Aqua holds the edge over the others here) with a Sponge Filter which is superior in bio filtration to most HOBs.
*Other filters include Internal filters such as the Via Aqua 302 or similar, Pre-Filters to attach to a Power (HOB) aquarium filter to expand bio filtration and prevent intake of fish fry
25-75 Gallon; Filter/pumps suggestions:
*A Canister Filter can be substituted for an aquarium power filter such as the Rena Filstar XPS or SunSun Aquarium 402 Canister Filter, although either a larger HOB Filter, such as the AAP Tidal 55 or 75, Aqua Clear 50 or 70, or two HOB Filters for better redundancy/circulation can be used (HOB filters also have the advantage of simplicity as well).
*As for HOB filters, my new recommendation would now be the AAP/SeaChem Tidal Filters such as the AAP/SeaChem Tidal Model 75. This filter has an unsurpassed warranty, top notch construction with similarities to the AquaClear but with more solid construction, lower flow by, and a skimmer feature too.
As with smaller set ups previously noted Sponge Filters make an excellent and unsurpassed compliment to a canister filter or HOB Filter.
The Hydro sponge #3 or #5 are the Sponge Filters to consider for this application. In aquariums of this size either an air pump or a power head can be considered. The power head is a slightly more complicated way to connect a Sponge Filter, but they can provide better horizontal circulation over an air pump (which is still an excellent way to run a sponge filter in mid size aquariums).
*An Internal Filter such as the Via Aqua 305 PF becomes a more viable option for additional circulation/filtration. These can also be used to power a UV Sterilizer.
50-150 Gallon; Filter/pumps suggestions:
*A Canister Filter such as the SunSun Aquarium 403 Canister Filter, Magnum 350, or Rena Filstar XPM can make excellent filters for larger aquariums. Beware though over paying for some Canister filters such as the Eheim, which is a good filter, however good marketing has convinced many that these filters are unsurpassed which is bluntly not true.
As well beware of Fluvals as I personally have not found these to be the most reliable canister filters you can buy despite their marketing (poor head pressure as well).
Rather than a canister filter (which many find frustrating) consider a Fluidized Sand Bed Filter coupled to a power head. For Planted Freshwater Aquariums, these filters or a Sponge Filter are a much better choice due to lack of CO2 stripping.
Although not as well known, these filters can out perform the largest most expensive canister filter (including some pricey Fluval models ) for aerobic bio filtration.
With an Internal Filter such as Multi Stage SunSun HJ-952 or HOB filter for added mechanical and/or chemical filtration can compliment your Fluidized Filter for superior filtration to a canister filter.
As well, for high bio loads, the addition of Fluidized Filter to your canister filter (or Power Head, Water Pump, Internal Filter) can greatly increase your Bio capacity due to their unsurpassed bio-nitrification abilities!
Although Canister filters are popular with larger aquariums, it is certainly not a necessity for good filtration. There are good larger HOB filters such as the Premium AAP/SeaChem Tidal 110 or Aqua Clear 110 or multiples of power filters (which is good for redundancy).
Using different brands/types of HOB filters can compliment each other.
For instance the AC110 has good bio capacity, but more flow by and poor mechanical filtration. The newer AAP/SeaChem Tidal Filters improve on the AquaClear in every aspect, including mechanical filtration, but still fall a bit short of cartridge style HOB filters if mechanical filtration is important for ones application. An Aqueon, Tetra, or previously mentioned API/Rena Filters can be a compliment in this case.
*As with smaller aquarium set ups, Sponge Filters (such as the Hydro Sponge #5 Pro) should not be ignored as potential filters or complimentary filtration. Many fail to realize that Sponge filters can and do work in large aquariums and even ponds. In fact the Hydro Pond 2 can be easily used in a large aquarium and will out perform a Aqua Clear 110 in bio capacity.
*Power Head Aquarium Water Pumps such as the Taam Rio 1000 or a Propeller Pump such as the Seio 530 can be used for increased water circulation and even aeration (most add air by both increased surface agitation or optional air diffusers)
Internal Filters such as the Multi Stage SunSun HJ-952 (210 gph) also make a good compliment for larger aquariums, but are generally not adequate for sole/primary filtration.
150 Gallon Plus; Filter/pumps suggestions:
*Multiple canister filters such as the Rena Filstar XPL or XPXL, Magnum 350, or the SunSun HW 303B or HW 404B work well. I have often connected these in a pre drilled method for a more aesthetically pleasing & functional aquarium filter installation.
A Micron Style canister filter such as the Ocean Clear can work well in such an installation (although these are poor bio filters and I do NOT recommend their use unless other filters with higher bio capacities are used in conjunction).
This diagram shows how to simply add a canister filter via the bottom of an aquarium. This can work for most any canister filter (not just the Via Aqua pictured):
Drilled Canister Filter Application
I will also note that many larger aquarium owners will opt for some of these newer over priced filters such as the Fluval FX5, however I strongly recommend against this due to lack of redundancy and for being over priced for actual bio filtration.
A vastly better alternative is to purchase a more affordable SunSun of similar canister filter AND a TMC Fluidized Filter.
With this combination you will not only be saving $$, you will also have a vastly superior biological filter system and $$ left over to purchase maybe another small redundancy back up filter such as a Hydro Sponge #3!
*Sump system Wet/dry filters also work well for extra large aquariums, and not to sound like a broken record but the previously mentioned Sponge filters (including Hydro Pond Filters), along with power heads, HOB, Internal Wet/Dry, can be excellent compliments or mixed filter systems.
*For fish such as Discus which I have found seem to prefer more gentle water flows, the use of multiple Sponge Filters is highly recommended (generally run by a combination of power heads and air pumps).
ADDITIONAL RECOMMENDED FILTRATION; FLUIDIZED FILTERS FOR PLANTED AQUARIUMS
As noted earlier in this article, the Fluidized Sand Bed Aquarium Filter is an excellent addition to a canister filter or simply a power head water pump for added aerobic nitrification (bio filtration).
More importantly for a planted aquarium a well designed Fluidized filter does not scrub off CO2 as can many filters such as sump style wet/dry filters (which should not be used for planted aquariums).
The use of a Fluidized filter powered by either a canister filter or power head water pump will provide top notch aerobic bio filtration that is unbeaten by most any other filter, while at the same time perform this function in a way that does not remove the organic nutrients necessary for aquarium plants that many other filters may.
ADDITIONAL RECOMMENDED FILTRATION; GERMICIDAL
*Without going in depth (this is not the intention of this article), I recommend that even a small aquarium should have a UV Sterilizer for disease prevention and Redox Balance.
I personally have a 5 Watt Terminator UV Sterilizer on a 14 gallon tank, which was quite easy to install and when considers the cost of fish, treatments, and simple frustration; I think this is a worth investment.
For a top notch Aquarium UV Sterilizer, there is no better model than the TMC 8 & 15 Watt Vecton Ultraviolet Sterilizer.
Another idea that can work with any filter system is the SunSun High Performance Submersible/Internal UV Sterilizers.
Unlike most submersible UVs sold for simple internal use or attachment to a smaller aquarium, this is a TRUE UV Sterilizer that perform important level 1 sterilization and aids in Redox balance (unlike the majority that are nothing more than clarifiers with short lives).
Another benefit is this UV Sterilizer has a large Sponge Filter inside, so it also is reasonable quality filter too.
The only negative for tanks much under 20 gallons is the size since it is approximately 12 inches by 4 inches. However do not let size convince you to purchase one of those low end UV so called UV Sterilizers that are very compact, but also mostly useless.
Please visit this article for MUCH more information about the use of UV sterilizers (including size, installation, etc.)
Aquarium UV Sterilization; Information & Correct Use
For heater, rather than try and match a heater to an aquarium size, I would recommend reading this article to help understand the effect of ambient temperature and more to purchasing the correct heater:
Aquarium Answers; Heaters
For Aquarium Heaters:
As with heaters I recommend looking over the many options in this fast evolving aspect of aquarium keeping by reading this article. Admittedly this article can be complex, but these aspects are important to understand what is truly important in aquatic lighting.
Even if your freshwater aquarium is meant to be a "fish only" aquarium, these fish can benefit from good lighting which includes LED lighting. Newr research into aquarium Redox shows that good lighting can definitely benefit fish.
For "fish only" you will not need as much lighting too; for instance a 60 gallon 48 inch long "fish only" aquarium would benefit from just  AAP GroBeam 600 Strips ( would be suggested or two 1500 tiles for a high light planted aquarium of this size).
It is also noteworthy that while the many LEDs now available such as the Fluval and Finnex will do a good job for fish or planted aquariums, these lights are still not nearly as efficient for output of light energy per input of electrical energy. Nor do any other LEDs have the IP water resistant/proof rating (IP67) that the AquaRay LEDs sold by AAP have.
Even more noteworthy is that these discounter LEDs only have warranties of as low of 180 days versus the 5 year full replacement warranty of the AAP AquaRay GroBeam. Even other premium LEDs only have 2 year warranties that are for REPAIR, NOT replacement. So consider your long term costs before you decide to join the LED "craze" and place your electronic LED with a poor warranty in a wet environment!!
Below is a 60 gallon Planted Aquarium utilizing AAP GroBeam lighting:
Please look as the Tank Set up Lighting Suggestions (near the bottom of the article)
A couple of basic lighting suggestions that are also more current in technology:
*Compact Fluorescent Lights
*T2 Aquarium Lights These are actually one of the best lights as per output and energy used, yet are still reasonably priced. Two of the 13 watt T2 light fixtures can light a 30 gallon planted FW aquarium or even up to a 100 gallon fish only freshwater aquarium for huge savings in energy without a sacrifice in light output.
Chemistry, Cycling more
*A simple Aquarium Test Kit suggestion is the API 5 in 1 Test Strips
Please read these articles for further aquarium set up information:
*Aquarium Chemistry; GH, KH, pH
This article includes information for different aquarium set ups, such as Amazon River Aquariums (Discus, Ram Cichlids, Angels, etc.)
*Freshwater Aquarium Salt Use
This article gives different salt use suggestions depending upon the type of fish kept.
*Aquarium Nitrogen Cycle
This article helps the aquarist understand the importance of the aquarium nitrogen cycle, with suggestions for cycling a new aquarium.