What Size Filter for a 29-Gallon Tank?
A 29-gallon tank needs 116 to 290 GPH of turnover. Buy a HOB (hang-on-back) filter rated near 261 GPH so real flow stays on target.
Quick answer
~261 GPH rated
Aim for about 174 GPH of real flow on a 29-gallon tank and buy a filter rated near 261 GPH so it still delivers after media and clogging.
A 29-gallon aquarium wants a turnover of 116 to 290 gallons per hour, with most community tanks landing near 174 GPH. Because a filter's rated flow drops once you load media and it starts to clog, buy a unit rated about 261 GPH. For a tank this size, a HOB (hang-on-back) filter is the right tool.
Filters for a 29-gallon tank
A hang-on-back filter rated near 261 GPH is the easy match for a 29-gallon tank.
Want more media capacity and quieter flow? A small canister works well too.
Confirm the filter is keeping ammonia and nitrite at zero.
How we sized the filter for a 29-gallon tank
Filtration is about turnover, the number of times the filter cycles your whole water volume through its media each hour. The healthy range is 4 to 10 times per hour, so a 29-gallon tank sits between 116 and 290 GPH. A normal community stocking is happy near 174 GPH, while heavy or messy fish such as goldfish and cichlids push toward the top of the band.
| Detail | Value |
|---|---|
| Tank size | 29 US gallons |
| Healthy turnover band (4x to 10x) | 116 to 290 GPH |
| Community target (~6x) | 174 GPH |
| Rated GPH to buy (~1.5x) | 261 GPH |
| Best filter type | HOB (hang-on-back) filter |
Why you buy rated 261 GPH, not 174
The gallons-per-hour number printed on a filter box is a best case, measured with an empty unit and no height to pump against. Load it with sponge, ceramic media, and carbon, and add a few weeks of debris, and real flow commonly falls 25 to 50 percent. Lifting water to the tank rim costs more. That is why we size up: a filter rated around 261 GPH still delivers your 174 GPH target once it is doing real work.
Which filter type for a 29-gallon tank?
At 29 gallons an HOB filter is the easy default, and a small canister works well too if you want more media capacity. Running an HOB plus a sponge filter is a popular, redundant setup. Whatever you choose, oversized filtration is cheap insurance: more media means a bigger bacteria colony, and you can always tame strong current with a spray bar or by aiming the output at the glass.
Dial it in
Run your real stocking through the filter size calculator to fine-tune the GPH, then round out the build with the 29-gallon tank setup guide.
Frequently Asked Questions
What GPH filter does a 29-gallon tank need?
A 29-gallon tank needs a turnover of 116 to 290 GPH, which is 4 to 10 times the volume per hour. A normal community stocking sits near 174 GPH. Because rated flow drops once media is added, buy a filter rated around 261 GPH so the real flow stays on target.
What kind of filter is best for a 29-gallon tank?
For a 29-gallon tank a HOB (hang-on-back) filter is the best fit. An HOB is the simple default, with a small canister as a higher-capacity upgrade.
Why buy a filter rated higher than 174 GPH?
Rated GPH is measured with an empty filter and no head height. Once you load sponge, ceramic media, and carbon, and as that media collects debris, real flow drops 25 to 50 percent. Buying a unit rated about 1.5 times your target, near 261 GPH, keeps the real flow where you need it.
Can a filter be too strong for a 29-gallon tank?
Slightly oversized filtration is usually a feature, not a flaw, because extra media means more beneficial bacteria. If the current is too strong for calm fish like bettas or fancy goldfish, reduce it with a spray bar, a flow baffle, or by aiming the output at the glass.
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