Sump fills up when pump is turned off....

I need some advise on my sump. I recently removed my spraybars and now when I turn off my sump pump the water would probably fill my house if didn't turn the pump back on quickly. I think this is backpressure coming in my output on my return. My question is how do I control this to prevent a flood if the power goes out. Thanks in advance.:-/

 

Drill a small anti-siphon hole in the return line right around where your water level is at.

~Will.

 

Place the returns just slightly below the surface so once a very small, easily calculated amount of water back siphons it breaks suction and quits.
An air gap is the only foolproof method of backflow prevention. Thinsg like drilled holes and check valves require mainenance and cleaning and even then can be defeated by a snail, anemone, fish, food, algae, or even grain of sand on a check valves sealing surface. An air gap requires no maintenance and will work every time.

 

IllWill,
Is that all I have to do? and what size drill bit?

 

DesertRat,
That is easy enough.....thanks for your help! ;D

 

I would not rely on a drilled hole. My tank has one and it never works. Only sure fire thing is placing the return just below the water line like AZdesertrat suggested... Jeff

 

We do both. Our return came with a drilled hole from the factory that's about 1/4"-1/2" below the water line. But then our return itself is only about 1.5-2 inches below the water line. Normally the anti siphon hole does its job and our water line in the sump increases by only a few inches (17g sump). But if the return has to break the siphon, only about 5 gallons will get into the sump, so it's still not overflowing or "close" (depends on your view of close) to the top. I think last time we tested with the hole plugged it was about 3 inches from the top of the sump. Still a fair amount of wiggle room for our backup siphon breaker. Plus, we have our return aimed at the surface, so it's closer than it would be to the water line.

 

you can also install a check valve between the pump/spray bar that only allows water to flow in 1 direction

 

NEVER rely on check valves in reef aquaria. A simple grain of sand can defeat it. Remember, it does not have to be a catastrophic failure, even a trickle will overflow the sump if the power is off an hour or two.
In the wastewater industry we avoid check valves like the plague and an aquarium is really a miniature wastewater treatment plant. You will have slime coatings, food particles, baby snails, any number of things that can and will plug a drilled hole or prop a check valve open.
The other disadvantage of check valves is they add additional head or back pressure on a return pump thus lowering its flow even more.


My display is a 60" long 100 gallon. It has about 4.6 gallons per vertical inch of water in the tank. My returns are 3/4" below the water surface so they break suction when 3.5 gallons are back siphoned to the sump and the flow stops, no ifs, ands or buts, its that simple. Nothing to fail and nothing to maintain. as long as I keep that amount of freeboard or spare room in the 30G sump I will never have a return related flood and can sleep at night. I actually keep about 8 gallons of room in the sump as this is the level my baffles are placed and where my skimmer works best so its never a problem. Just remember to never fill the sump past that safety factor point even if you are going to be away a few days.

 

Actually thats not true. You can safely rely on the anti-siphon hole. Just make it big enough and put a small piece of sponge under it so nothing blocks it. Air will stil go through and will reduce noise and water splash. Works like a charm

If you dont want a sponge under the anti-siphon hole, get yourself a filter media bag, cut it to a small size and put tiny amount of carbon or whatever media in it, then tie it to the pipe underneath the hole using fishing line.

Free carbon reactor