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View Full Version : too much flowrate from overflow box


sunjai
04/06/2007, 04:54 PM
hello
this question might sound stupid to you guys....
but i just wanna make sure i'm doing this right.....
i was looking at the CPR C-Siphon Aquarium Overflow - CS90 Deluxe (600GPH) which will fit my return flow "around 350-400 after head loss"
but i saw this CS102 Deluxe (1200GPH) which have two 1" Bulkhead which I can direct flow to skimmer section and my fuge without using a split.....
so my question is will the 1200GPH overflow box going to cause a problem??????

GL
04/06/2007, 05:18 PM
you may not have enough flow to keep the syphon from breaking frequently pushing that low flow thru the 1200 gph overflow.

Also, unless you are using some type of recirculating pump in the skimmer you may not have sufficient flow for the skimmer efficiency.

sunjai
04/06/2007, 05:23 PM
so do you think even if i use a 600GPH overflow box...
I may still not have enough flow to keep the syphon from breaking frequently pushing 350 flow thru the 600 gph overflow??

Shagsbeard
04/06/2007, 05:26 PM
Not just syphon... it's going to be noisy. The drain is going to suck water faster than the syphon can supply it, so you'll get slurping.

marduc
04/06/2007, 05:58 PM
With the CPR overflows, the siphon will not be an issue since they need to have a pump running attached to the airline tubing hole at the top of the box, run an aqualifter pump from this hole and it will continuously pull the air out of the overflow, maintaining a siphon at all times.

Noise/gurgling could be a potential issue with the lowered flow, but there are ways around this. First off would be to instal 2 ball/gate valves just after each bulkhead (just good plumbing practice to begin with so you can remove the device and clean it anyhow). If it gurgles you can play with opening/closing the valves until they get quieter, either that or you could make a modified durso standpipe to fit in there using a "T" pipe instead of an elbow to connect both overflow drains (do a google search for durso standpipe if needs be on this :))

My gut feeling is that it won't be that noisy.. run the drain pipe as verticle as possible for as long as possible, and there will be even more area at the top of the pipe for the "gurgle" causing air to escape due to the lowered flow.