View Full Version : microbubbles stopping siphon

04/11/2010, 07:54 AM
I just setup my new sump with a cpr overflow, octpus 160 extreme skimmer, and quietone 5000 return pump.
The pump is a bit too powerful for my 75g, but the way I have it hooked up, it runs to a chiller then to a scwd and thru two returns to the tank.

the problem is there are tons of microbubbles coming into the tank and they make their way into the siphon of the overflow and break the siphon eventually.
Just to experiment I put a small piece of spong, approx 5inx 1inch into the intake of the overflow to stop the bubbles.
first, do oyu think this will stop the bubbles?
second will this cause much of a nitrate problem if cleaned weekly or bi-weekly?

my sump is divided into skimmer and return chambers, separated by the regular over-under-over (3) baffles.
I think since the skimmer is still breaking in I might be getting the microbubbles.
or it could also be because I've reduced the return pumps output from 1inch to 1/2inch (only for a length of 3-4inches) and back to 3/4 inch for the entire length.

so again, how can I stop the bubbles in the overflow breaking the siphon, and will the tiny sponge cause nitrates?

thanks guys

04/11/2010, 09:27 AM
I would be more worried about the tiny sponge clogging and causing an overflow.

CPR overflows are going to have this issue no matter what you do. They are designed to be used with an aqualifter pump. It's a bad design and requires weekly cleaning of the nipple that the aqualifter plugs into.

Do yourself a favor and hook your return pump to a in tank ato from autotopoff.com or similar. If for some reason your overflow fails the ATO will stop the return pump and will stop the flood from occurring. I would never run a CPR without it.

04/11/2010, 11:16 AM
I dont have access to a aqualifter, plus they are 110v, and I need 220v here.
Can I hook the nipple on top to a tube tunning to a powerhead in the fuge?
you basically the nipple will act as a venturi in the pump.
think this will work?