Limiting flow/turbulence from HOB filter

[gzeiger]

I have a 75-gallon tank with a 300 gph HOB filter. Initially the high water turnover was good for filtration, but as I've added more and more plants it seems increasingly unnecessary. I've just added a CO2 system and I'd like to limit flow so as to keep more gas dissolved. I've raised the water level until it no longer splashes, but what I have now is a strong circular current at the surface. I'm also looking at a couple fish that dislike current and like to just float at the top, so I'm looking for a way to either reduce the flow or direct it downward again.

I have a similar problem in my feeder tank, which is a 5 gallon with 40 gph filtration. I want to adapt that tank to house fairy shrimp, which are very weak swimmers.

I'm thinking about just sticking a sponge in the outflow, but I suspect I would just end up with a higher water level in the filter box and water overflowing the top of the sponge.

Any other ideas?

 

[Egress]

I've used aquaclear sponges as outflow baffles with good results. These sponges are a rather coarse open cell foam, so too much restriction wasn't a problem. I was using less powerful HOBs, though, rated in the 200GPH range.

 

[CaptainAhab]

pvc tube mounted horizontally (capped). Partial cut off to a half tube where HOB will flow into, holes drilled in the remainder.. Whamo, instant spray bar.

You'll have to play with the hole size until you get the right size without the cut end just spilling over.

 

[Nyquil Junkie]

http://www.aquariumadvice.com/forums/f20/wintertime-experiments-a-sponge-box-111212.html

Try a sponge box!
lol

it cuts the turbulence to zero.

 

[BillD]

What brand of filter? If it were an AquaClear (mini up to a 70), a smaller impeller could be installed.

 

[gzeiger]

This sponge box thing works great! Thanks for the ideas.