Confused about a check valve.....

[lazyreefer]

Dazed and confused.... :squigglemouth:


I woke up this morning to 15 gallons of tank water on the floor, an overflowing 40 gallon sump, and a 175 gallon system down to 1.021 from 1.025 salinity.

Every so often, when my 12 gallon ATO reservoir is completely full, the Maxijet pump inside the ATO turns on to fill the tank like its supposed to - but when it shuts off water continues to siphon out of the ATO and into the sump.....very slowly but enough.

What sort of "check valve" can I install that will allow the water to flow when the pump is on, but will keep the water from flowing in the same direction when the pump is off ? I know a "regular" check valve allows water to flow in one direction only, keeping it from back flowing, but in this case I need the flow to turn on or off in the same direction.

I had a similar problem on my other system, its 8 gallon ATO reservoir is right next to the sump. The hose is flex inside the ATO reservoir but then is 3/4" PVC into (above) the sump. Its shaped like an upside down U with one leg fully submersed inside the ATO but the other leg is above the sump.

The siphon from ATO into sump occurred on that system whenever the level in the ATO was higher than the level of the second leg of the upside down U. Hence, by raising the level of the second leg higher than the water level in the ATO reservoir, no matter if the Maxijet was on or off, no siphoning could occur.

The problem was the **** leg kept dropping resulting in my sump overflowing. I ended up drilling a hole in the hard PVC near the top of the leg which eliminated the problem by letting air in stopping the siphon - BUT, now when the pump turns on water spouts out of that hole. Its right next to the sump so thats not a big deal.

It is a big deal on this other setup because the ATO reservoir is not next to the sump, I'm running about 10' of flex hose from the Maxijet in the ATO into the sump. (with "dips" I might add) There's no way to raise the sump and/or lower the ATO and being inside a cabinet with electrical connections I'm concerned about hard plumbing the very end of the line and drilling a hole in it to stop any chance of continueing flow when the Maxijet shuts off. I don't want water spraying out of the hole onto the electrical connections.

This is why I'm wondering about any sort of check valve. I would add, I went into greater detail than necessary in case anyone else is having a similar problem. I was stumped for a long time wondering why my sump was oveflowing because I never actually saw the siphoning occur. Once the level in the ATO got lower than the end of the U...the flow stopped. It was quite a mystery to me why I had water on the floor...I attributed to a snail in the return line for a while there.... :sad:


PS....the MaxiJet inside the ATO is basically on the floor, while my flex hose is about 2' above that. I struggle to understand why a siphon still occurs in the first place when the pump is lower than the end of the hose. The hose is lower than the level of water in the ATO when it overflows, is pressure forcing the water through 10' feet of flex hose with a couple of dips, rather than a siphoning action ?? (sort of like having a garden hose filled with water, raise one end and the water pours out the other)

 

[jaytizzle]

It will siphon if the water output is lower than the water level in the reservoir. The easy fix is to put the hose from the pump higher than the water level in the reservoir. If that would make the water fall from the end of the hose at too high of a level and cause splasing, you could still end the hose at a higher level and make a sort of funnel or catch with a drain line down to the sump. As long as there is an air break in the hose (i.e. an opening) above the reservoir water level you won't siphon anymore.

 

[Troylee]

there is nothing confusing about check valves...THEY SUCK AND WILL FAIL!!!!!!! it has been said a million times it's not if?? but when!!! they always fail....:(
the cure for your problem is to get out the out put hose out of the water in the sump..keep it above the water level in there so it runs down the wall of your sump or drips into the sump "noisey" but either way will prevent the sphion from continuing because there is air it break the sphion...hth..

 

[lazyreefer]

No check valve huh.....was kind of hoping I could scoot on down to Home Depot and make short work of it.....dang.

I wonder if all pumps have this same potential to allow water through, if there was a clear shutoff path within the pump itself this wouldn't happen. Its this "shroud" on the pumps that allows water back into them that is the root cause of the problem.

 

[lazyreefer]

Troy, that's not the cure, the hose on either system has never been in the sump. Its exactly like Jaytizzle posted, its the water level in the reservoir being higher than the end of the hose that causes it, just like a garden hose analogy I used.

Its PITA....


PS......Its really not a siphon at all, but rather "pressure" from one level being higher than the next. I used to build decks, we used a clear hose to level a broad expanse say 40-60 feet....when both ends of the hose are the same height, no water comes out of either end, your level. (Its known as a water level) This works within deep ditches or hills, the idea that it was a siphon was the part that was messing with me for a long time.

 

[Troylee]

i have never ran across this problem besides when my hose was in the water on the sump... the only thing i can think of is i keep my aqualifter pump on top of both resivors so maybe that causes it to stop.... try setting the pump above the sump and ato resivior i bet it stops....:)

 

[lazyreefer]

Thanks Troy, I was kind of figuring that a whole new way of delivering the top off water might need to be considered. But really, I've got a really nice setup its just the Maxijet has to be down on the bottom and submerged.

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I'm gonna plumb the end with PVC and drill a hole right at the top - which would be just underneath my display tank inside the cabinet. I'll have to rig up a deflector of some sorts to keep any water that shoots out the hole from spraying all over the place.