View Full Version : Wet/dry filter problems

02-16-2004, 01:32 PM
I know many of you don't use wet/dry setups for discus but for those who do, I need some help. I set up a 175 gallon bow front display tank this weekend with built in overflow boxes. I put 2 small oceanic sump filters under it, one for each side. I did this because a single sump of adequate capacity would not fit unless I built a complete custom set up. When I filled the system and started it running, the right sump fills faster than the left one so the pump in the left sump manages to pump itself dry in just a few minutes. I can't figure out why this happens. The tank appears to be level, the hoses and plumbing are the same to each side. Anybody run into this problem? How do I fix it? I don't want to build a new sump.

02-16-2004, 03:00 PM
This sounds like a water circulation issue in the tank itself.
Are the return flows symetrical?
What are you using for a heater(s)? Where is/are it/they placed?
Is part of the tank in sunlight?
Is there a heater vent/radiator or air Conditioning unit near the tank?

I am thinking that you may have a water current that is causing your issue.
I use 1" (2.5 cm) square pieces of pantyhose to determine water currents inside the tank, throw about a dozen in the tank and watch. Be carefull not to let them clog your pumps (overflow should take care of this).

You will probably find that the current inside the tank is the cause.
Other than adjusting the causes which is usually a pain, the only way around this I've run into is to use a valve to reduce the flow, (in your case on the left sump).

Hope this helps.

02-17-2004, 11:25 AM

Lets not try to overthink this, in perfect situations, this will happen with dual sump systems.

I have run wet/dry for years, including dual systems like yours. I have a dual system right now and the only way to maintain an equal level is to add a syphon hose between the two sumps. You can mess around with little valves on your pumps all day, but eventually one pump will out work the other and you'll have a wet carpet.

You start the syphon, just like with the J tubes in your overflow boxes. Stick a small tube in the larger tube and such the air out. Use a large tube with some flexibility so it can stay ahead of the situation and cut it so the ends are near the bottom of the sump to avoid air breaking the syphon if you let your water level drop.

Email me if you have anymore questions,


02-17-2004, 11:54 AM
Thank you for your reply. I had come to the same conclusion and am picking up the stuff today to set up the siphon. My plan is to do it with 2 j-tubes made out of pvc and a connecting hose. I will e-mail you if I have nay trouble getting it to work. It seems though that if I basically convert two sumps into one with the siphon then all should be ok.

I would appreciate your comments about how many bio balls I need for this fresh water set-up. There seems to be a lot of debate about wether or not you truly need 1gallon of balls peer 30-40 gallons of water.