PDA

View Full Version : sump returns


hodge_williams
10/05/2008, 09:38 PM
I currently have a return setup that returns via a 20mm pvc pipe that runs over the tank and then goes into the DT via a 45mm bend. I have moved the angle a few times so the water spray is as high as it can be without slashing. It is currently hitting theglass on a 45mm degree but it still slowly moves the sand and clouds the water.

I am looking at changing the setup so that it drops into the tank in the middle near the bottom blowing up using a t piece with 2 45 degree angles. My question is that as the return will be well below the water level if I turn my return pump off for any reason will the vacuum/suction suck all the water out of the DT into the sump?

Aqua Keepers
10/06/2008, 04:35 AM
Yes, unless you drill a siphon break hole @ the water line in the dt. If you do it this way, you need to keep an eye on the siphon break hole as it can clog.

FranktheTankTx
10/06/2008, 06:31 AM
Drill 2 - small holes on the back side that won't be visible. I recommend 2 so that if one stops up or for some unbelievable chance a snail is resting on one the other will break the siphon.

As the other poster said - drill them just slightly under the water line.

AZDesertRat
10/06/2008, 08:28 AM
DO NOT rely on drilled holes to prevent a flood, they can and will plug. This is a false sense of security and will fail, could be tomorrow or next year but it will fail guaranteed.
Keep the return close to the surface so you have a positive air gap once the level drops an inch or so, this is the only positive foolproof method of backflow prevention.
To lessen the impact on the sand bed why not install some LocLine flexible tube with a fan type nozzle or two to diffuse or fan the flow out gently.

FranktheTankTx
10/06/2008, 09:01 AM
I should have said that I don't recommend drilling small holes, too. If you have to, then ok... but I'm with A.J. - keep your return as close to the surface as possible.

Aqua Keepers
10/06/2008, 06:24 PM
Ditto. My return is just below the water line. I'd use a 90*/45* elbow to direct flow. Keep in mind that even with the return just under the waterline, you will still have a small amount of back siphon and will need to make sure your sump can accommodate the extra water.

hodge_williams
10/07/2008, 12:01 AM
thanks guys... I also thout in using a once way valve but have since avoided this whole scenario. I ended up up using a 90 to a t-piece and 45's on either outlet of the t-piece. no more cloudiness and cannot see substrate moving at all.
Thanks for all the help guys, really appreciate it!

AZDesertRat
10/07/2008, 07:24 AM
Don't use a check valve either, worse than drilled holes for failures. All it takes is a grain of sand to defeat it.