DIY sump

[blackthunda77]

i got this over flow and this return pump that im trying to use in my diy 10 gal sump. the problem i am having is that #1 it seems that the pump is pumping out water faster than my overflow and put in into the sump, so my tank is over flowing and and my sump will run dry in a matter of 10-20 sec. also once i unplug the pump the return line keeps draining water back iknto the sump making that over flow, same goes for the overflow, itll keep sucking out water until it gets lower than the grooves in the overflor box. the pump i got is from someone and its the mag drive 7 i think its rated at 700gph. the overflow i got from him is only a single. can the pump be too stroong for the overflow and how can i get the return lines and the overflow to stop sucking water once the pump is off in case of a power outage, and when the wers out how can i keep the lines primed to get it to start back up on its own. someone pleae help. im gettin frustrated.

[Brisc0]

Put a ball valve on your return line so that you can control the amount of flow going into the tank and equalize the Drain:Return. To keep back siphon from occuring you can either put a check valve on your lines or you can drill a couple of small holes in your return plumbing just below the water surface so that siphon is broken when the return starts sucking water back into the sump.

[blackthunda77]

but siphon wont stop until the water level in the tank draind down enough to reach the hole in the return line correct?? also what are tose check valves and how do they work?

[wrkalot]

I had the same type of problem with mine. Turned out I had an obstruction (nitrate sponge bag) in the sump above the bio balls where the water enters the top of the sump. I switched to a Mag 3 drive before I realized this (which also didn't work before I removed the bag). Be sure that there are no obstructions in the hose from the over flow box to the sump.

I still think the Mag 7 would be too much for mine. It looks like the Mag 3 is pushing the upper limits.

[wrkalot]

I would drill the hole .25 inches from the water line.

Power outage: if you have a round "U" tube that goes from the box in the tank to the box on the back of the tank (and they are both submerged) it will start siphoning automatically when the power comes back on.

[Brisc0]

what are tose check valves and how do they work?

A check valve on lets water move one way. When the water tries to run back down the line it isn't able to drain.

[Centurion]

check valves for the most part are reliable, however i would still drill an anti-siphon hole in your return line.

a ball or gate valve will allow you to cut back the flow of the return pump. start closed and slowly open in up until the overflow cant handle it then throttle it back a bit.

[blackthunda77]

can i get a check valve at home depot or lowes? and is that what i ask for a "check valve"? maybe a stuupid question but they come in diff size diameters also like pvc correct?

[Anemoneman]

check valves for the most part are reliable

I disagree with this. IME check valves become obstructed with gunk and will not seal.

a ball or gate valve will allow you to cut back the flow of the return pump

An excellent suggestion.

[Brad]

Depends on the size of your plumbing. I was using 1/2" ID pipe, which I thought was pretty common practice, yet I couldn't find a 1/2" ID check valve anywhere. You'll need to go to a plumbing specialty place or order from an online aquarium supplier.

You're describing a situation I call "reverse siphon". When the power stops, the pipe that normally sends water INTO the aquarium suddenly becomes a siphon and starts pulling water OUT of the aquarium. The check valve prevents this.

The other suggestion is to drill a hole in the pipe just as it enters the aquarium. It has to be a pretty large hole. The thought is that when the pipe starts to reverse siphon, it will only drain down to this hole. Once it hits that point, the hole sucks air into the line breaking the siphon.

In my experience, that hole has to be pretty large to interrupt the siphon action. In my case, the hole would suck in a lot of air, but the siphon would merely slow. But if the hole is large, a lot of water shoots out the hole when the system is running...

Finally, the ultimate security is to only have enough water in the sump so that the system can reverse siphon all it wants, the sump will still handle it. This is controlled by the water level in the sump and the depth of the return pipe in the aquarium. Run less water volume in total...and alter the depth of the return pipe until you've got it set.

[alarmguy66]

I am using a mag 7 and an overflow with a single 3/4" output. Tuning the 2 took a few hours, but wasnt really hard. I put a 90 degree elbow at the surface where the water returns to the tank. This returns the water to the opposite side of the tank as the overflow. If the power goes off, the water level in the tank drops an inch until the water reaches the opening of the return line, then the air stops the siphon. I put a mark on the sump so I know how much I can top it off with and not risk flooding in the case of a power outage.