how to stop back flow to sump????

[bromion]

<a href=showthread.php?s=&postid=7402109#post7402109 target=_blank>Originally posted</a> by tptp279
you have a u-tube type of return that hangs on top which sprays water into the tank. That is where you drill the hole, on that u tube return. drill it on the side where it is spraying back into the tank.

That makes sense. I think we were mixing "siphon" and "return" or something. Thanks!

 

[ghever]

I have a wye check valve.. supposed to be the best... anyways, mine gets stuck so I have to clean it everytime I do a water change....I already had a flood once when power went out, valve was stuck, water overfilled the sump and went on the floor... then my auto top off pumped in more freshwater..

RESULT... lower salinity, minor flood on floor.

With my new tank, my returns are coming over the top of the tank and pointing straight down...I dont think I'll need to drill a hole side the returns will be right at water level.. but if you have returns from your pump, yah, you need to drill a 1/4in hole, at 45 degree angle... this actually will cause a suction and pull water in instead of pushing it out when pump is on... when off, it will suck in air and break the syphon.

Dont trust ANY check valves... and if you use one, use a hole drilled as well... the check valves should be cleaned regularly.

G