Sump "flushing" issues

[shakta]

I recently bought ~100gal tank w/ 20gal sump, just starting my setup, and am having issues where every 30 or so minutes water starts flushing down the sump until it starts to balance out again. Sometimes it flushes 1 time sometimes it's 10 times and it's driving me crazy.

I'm pretty new to SW tanks and reefkeeping. here is some ascii of the setup. It's about 1.75" pvc piping and the previous owner designed it to be very quite. I've tried adjusting water levels and briefly tried covering the botom pipe with a sock. removing the air valve at the bottom

The sump also has a G3 skimmer and a mag 12 return pump. Has anyone else had this issue of the tank to sump flow never fully equalizing out?

__ __ __ <-- bottom of overflow

} 3-4 inches

--- <-- there is a small pinhole in the cap.
| | <-- I keep a filter here to keep the waterfall quite.
| |___
| .......|
| -- ...|
| | |...| <--- water intake
| |
| |
| |
| |
| |
| |
| |
~ ~ bulkhead
| |
| |
| |
| | fully open "T" valve here
| |
| |
| |
| |
| |___|...| <-- air intake (pvc cap w/ holes drilled in)
| ______|
| |
| |
| | <-- water level in sump (covers ~bottom 1-2" of pipe)
| |


Thanks
eric

 

[kgross]

You need to increase the size of the pin hole in the very top of your stand pipe. Yoru stand pipe is basicly a Durso setup. If you do a search for Durso you will find a lot more info.

Kim

 

[shakta]

Interesting, I see now i have the durso siphoning issue. I'm reluctant to change anything just yet since the person who owned it before me said it never siphoned on him. I'm thinking about replacing the pipe under the bulkhead with a few feet of pool hose. Maybe i'm getting some kind of water backup in the line that eventually leads to siphoning.

Thanks
eric

 

[kgross]

If the previous owner had a lower flow rate from the sump it would not flush. So is the setup exactly the same, or did you change the pump or plumbing to increase the flow? If you did that is what is causing the problem, with the higher flow you need more air in the durso.

 

[deadmanh]

the T valve that you say is FULLY open.... try SLOWLY closing PART of it off..... NOT al the way... this is part of an idea used in another thread, ill see if i can find it for you.

 

[deadmanh]

http://www.reefcentral.com/forums/showthread.php?s=&threadid=344892