Sump Overflow Avoidance

jesterns2 · Jan 3, 2010

The construction of my sump/refugium is complete. This Friday I plan on getting vinyl hosing and other plumbing parts that I will need. I will be using a CPR overflow box with a Aqualifter. I have done research on this subject but want to make sure I dont have any flooding issues or any others for that matter.

I have a 75g tank (120lbs Live Sand 130lbs Live Rock), 29g sump, CPR Overflow is 300gph, mag 5 return 500gph but with head loss im looking at no more than 350gph.

My baffles are 10" high, leaving me with enough room in the sump for 10.5g of water should I have a power failure. I don`t plan on putting the overflow any deeper than 1' below the surface because I do want to skim the top of the aquarium. In my aquarium 1" of water equals 3.74g and in the sump its 1.7g for every inch so I should be ok. Also I plan on putting two small holes in the return to break siphon a half inch below the water level and probably a ball valve so water can`t flow backwords.

Please tell me you`r suggestions I would greatly appriciate them, Thanks Bill

Paul_N · Jan 3, 2010

I have had the weir type and U-tube over boxes and both can be a pain with loosing siphon. I wish I would have drilled but with that being said I never lost siphon completely it would just get air pockets in tube or weir and slow the overflow down a bit. Just make sure you regularly(monthly) clean the connector for the airline to the top of the weir because that will get clogged over time. You look like you have the main points covered with the siphon break holes and room in the sump for the display tank to drain in the event of a power loss. IMO, if you have a the siphon break holes and room in the sump calculated properly there is no need for a valve (check valve). It's also just another thing you have to take apart and clean and worry when it will fail.

jascymcl · Jan 3, 2010

agree will paul psu on the check valves had them fail before

jesterns2 · Jan 3, 2010

That would really be a bad thing!!!

cloakerpoked · Jan 3, 2010

If you had a high grade check valve, you'd be fine, but just the standard PVC ones you can pick up at Lowe's I wouldn't trust. Not for the length of time you'd want to use it anyway. Siphon break holes are all you'll need.

jesterns2 · Jan 11, 2010

Just thought i`d send an update on the sump. It`s up and running, no flooding occured so my marriage is safely in tact LOL!! I did have a little leaking from the bulkhead but I seem to have gotten that under control and also we had to use a piece of I believe 3/8 vinyl tubing to put onto my return and then put my 1/2 inch return line up into that. I did get some leaking from that but put a couple zip ties on and they seem to be doing the job. As it turned out when I cut the power to the system I still have 4 to 5 inches of room left in the sump before it would overflow.

Paul_N · Jan 11, 2010

Nice to see you have it running. Gotta keep the wife happy lol. I'm not looking forward to breaking down my 75 and my wife seeing the hardwood floors under the stand after I having my original external skimmer overflow a dozen + times. I used zip ties on my return also for the tubing.