Need a little help

[Breakthecycle2]

I made a thread awhile ago, but I can't find it now, so I have to make a new one. My issue is, when I shut the return pump off, sometimes the siphon created overflows the sump. I can catch it now, because I hear one side of the returns sucking in air, so I lift it up out of the water. For the first few months it never did that. I shut the pumps off, it stops completely. The return lines are about an inch below the water line, so when the pumps are off, they are never exposed out of the water. Even if I drilled a hole to break the siphon in the return line, it wouldn't matter I don't think. Any suggestions?

 

[rajkovich207]

No a drilled hole in the return line just before the split would work fine, give me a sec and I'll dig up another option and edit my post.
Here's one better, this is the video of it in action and the how to link is in the description.

 

[Breakthecycle2]

No a drilled hole in the return line just before the split would work fine, give me a sec and I'll dig up another option and edit my post.

Both of my returns are not together. There is one on either side of the tank. They are separate.

 

[rajkovich207]

Do your returns come up through the tank or over the back? A pic of what you are working with would be great.

 

[Breakthecycle2]

Not the best picture, but this is all I could find. Im not home presently.

 

[Breakthecycle2]

The returns do come through the back.

 

[Diesel]

Through the back, mmmmm not sure how to kill those other than with a check valve or move the outlets up close to water level.

 

[Breakthecycle2]

Through the back, mmmmm not sure how to kill those other than with a check valve or move the outlets up close to water level.

Thats the thing. I have a check valve on both sides, which is why I don't understand what's going on.

 

[Lenny_S]

If I zoom in, the returns look very low. The outlet should be barely below the surface of the water. Ideally the returns and the overflow both stop siphoning at the same time when the pump is off. (i.e. they are at the same water level) The other thing is how much total volume do you have in your sump and how full is it when you are running normal? You want the sump and chambers to be designed to both hold the siphoned water from the tank when the pump is off and the return chamber should be sized as to not overflow the tank if the drain stops.

 

[Breakthecycle2]

If I zoom in, the returns look very low. The outlet should be barely below the surface of the water. Ideally the returns and the overflow both stop siphoning at the same time when the pump is off. (i.e. they are at the same water level) The other thing is how much total volume do you have in your sump and how full is it when you are running normal? You want the sump and chambers to be designed to both hold the siphoned water from the tank when the pump is off and the return chamber should be sized as to not overflow the tank if the drain stops.

So the sump could be too small?

 

[Lenny_S]

Yes, or too full while running normally. I have a 160 gallon tank 24" tall. So I have about 7 gallons per inch of water in the tank and I run it about 1.5" from the top of the tank. My sump has 60 gallons total capacity, but I only run it 60% full or a little less than 40 gallons while running normally. So I have 20 gallons of spare capacity in the sump or in other words about 3" of water from the tank. So as long as I don't drain more than 3" from the tank when my pump is off it will all fit in the sump. Conversely, my return pump chamber is barely big enough to hold the pump. That chamber runs with about 3 gallons of water in it. Even if I close the drain and I empty my 5 gallon ATO and pump that into the tank, it has enough space to not overflow. Here's a picture.

The chamber is only 8"x15" but the level is kept at 6" deep. And I don't have any more than 5 gallons of top off.
A lot of people account for a power failure and back siphon, but not everyone accounts for a stopped drain. It's better to account for both IMO.

 

[sc8kv123]

You could get a siphonstopper. They are designed for drilled tanks.

 

[sc8kv123]

Here's a pic of one

 

[Breakthecycle2]

The total dims are 38x20x16, but it has an 18-20 gallon (ish) ATO built in. I cant find the dims of the three chambers.

 

[Breakthecycle2]

Here's a pic of one

My returns are 1". I don't think they make them in 1".

 

[Lenny_S]

Those dimensions come out to about 50 gallons total volume. If you take away 20 gallons for the ATO reservoir you have like 30 gallons total capacity for the sump. If it runs normal at 50% you have 15 gallons spare capacity for back siphon. I don't think you put the dimensions or capacity of the DT, what are they?

 

[Breakthecycle2]

Those dimensions come out to about 50 gallons total volume. If you take away 20 gallons for the ATO reservoir you have like 30 gallons total capacity for the sump. If it runs normal at 50% you have 15 gallons spare capacity for back siphon. I don't think you put the dimensions or capacity of the DT, what are they?

Yeah, that would help. It's 200 gallons.

 

[Lenny_S]

How tall? If it's 24" tall then that's like 8.5 gallons per inch. If all my other assumptions were right, then that is only a little more than an inch and a half from the tank to overflow your sump. That is not much. And would be even less if the sump runs higher normally or has a lot of equipment in it displacing volume.
IMHO, you need to just get the return outlets as high as you can. Your sump is a bit small for that big a tank. But I don't think you should worry about replacing the sump, just get the returns up higher.

 

[Breakthecycle2]

How tall? If it's 24" tall then that's like 8.5 gallons per inch. If all my other assumptions were right, then that is only a little more than an inch and a half from the tank to overflow your sump. That is not much. And would be even less if the sump runs higher normally or has a lot of equipment in it displacing volume.
IMHO, you need to just get the return outlets as high as you can. Your sump is a bit small for that big a tank. But I don't think you should worry about replacing the sump, just get the returns up higher.

The dims of the tank are 72"x28x22". I think I might have to go bigger in the sump department. What size would you recommend?

 

[Lenny_S]

What a shame, that looked like a really nice sump. I would go with 80-90 gallons not including any kind of ATO reservoir. And if you do get an ATO reservoir, keep it modest, 6-8 gallons. Just keeps it safer. I've heard many a story of ATO system failures that empty the entire volume of mega reservoirs into the tank. It obviously makes a big mess and could potentially crash your tank with a large sudden drop in salinity.