Size of AquaClear power filter for 20 gal tank

[LinY]

I am thinking of purchasing a Hagen AquaClear power filter for my established tank. The directions say I would need a #30 (rated for up to 30 gal) for my 20 gal freshwater tank. If I use a larger size (like a #50 which is rated for up to a 40 gal tank) , would it filter better? be overkill? wasteful? Not worth it? potential problems? Any opinions?

[Cliff]

I am thinking of purchasing a Hagen AquaClear power filter for my established tank. The directions say I would need a #30 (rated for up to 30 gal) for my 20 gal freshwater tank. If I use a larger size (like a #50 which is rated for up to a 40 gal tank) , would it filter better? be overkill? wasteful? Not worth it? potential problems? Any opinions?

If it was me, I would use the AC50 on a 20 gallon. You can adjust the flow or use a flow diverter so the water flow will not bother anything in the tank

[robflanker]

I have two AC50s on my 30g

I would use an AC50 without a doubt. A filter is really good for half of what it claims - there an AC50 is good for about 25g, and thus perfect for a 20g. One AC50 won't be overly powerful in your tank

You could always go with two AC30s instead

[Northernguy]

I have two 20s on a 20 gal now.I think it could use more.
I would go with minimum two 30s.A 50 would work well but the current may push a small fish around pretty good.

[EmmanuelJB]

Yup, An AC50 or 2 AC 30s.

[Sasquatch]

It will depend on what you have in your tank. If it's non-planted and you want to push the stocking, definatly go for an AC50 or 2x AC30s.

On the other hand, if you have a heavily planted tank or a tank with a very low bioload (Invert tank, grow out ... ) or fish that don't like too much current, a single AC30 will be fine.

[Lady Hobbs]

Let's not forget you are talking of a tank a foot high is all. Too much filtering is going to be throwing that substrate all over the place.

[toddnbecka]

I found that a piece of plastic canvas works very effectively to diffuse the flow. Simply cut it to fit the width of the outflow opening and long enough to extend into the water, then bend and crease it to maintain the proper shape. If necessary you can hang it over the inside of the filter as well, and use the media to hold it in place.

[Cliff]

I found that a piece of plastic canvas works very effectively to diffuse the flow. Simply cut it to fit the width of the outflow opening and long enough to extend into the water, then bend and crease it to maintain the proper shape. If necessary you can hang it over the inside of the filter as well, and use the media to hold it in place.

Below is a link to a DIY post for just what ToddnBecka explained

[Only Registered Users Can See Links.]

[toddnbecka]

The idea is the same, but I have plastic canvas lying around so I used that instead. It may actually be more effective for diffusing the current because the water flows through the mesh rather directly than over the top. I have an aquaclear 110 hanging on the side of a 75 gallon tank.
My goal was to prevent the amazon frogbit from being pulled under by the outflow and piling up under the surface. I had noticed that the surface was covered with frogbit, and took out enough to cover 1/3 of the tank. That allowed the rest to spread out, and it completely covered the surface again. The second time I removed more frogbit the duckweed filled in the space, at least until enough of the frogbit was piled up by the outflow to leave some open water at the other end of the tank.
After spending several hours cleaning the tank on Saturday I did remove all the duckweed, filling a gallon ziploc with that and excess frogbit. I still have enough frogbit remaining to help control nitrates, and in another 3-4 weeks the surface will be completely covered again.