Break Siphone

[bmkj02]

Hey guys,
So I have been out for a little more than 2yrs. My 125g burst open one night at 3am and it went ehhhh. I had a 250g sitting in the back yard so I figured lets build a stand. Then I got lazy

Will last week I was finally coming to an end with pushing from family and friends. I have a Hammerhead running this and I feel it may be too much. Its 1 1/2"in and out. The out breaks out to two 1" sea swirls and also two 3/4 return lines. Its running my sump dry. Now I can add more water and it will run fine but I for some reason the power was to go out the return line siphons a lot of water back which will make it over flow and make a mess. On my other tank I had drilled a small hole and that would break the siphon. With the sea swirls I don't see that happening. What can I do?

I thought of check valves but don't want to put my trust on those and don't want to spend $100 on one check valve. I know there are others cheaper but you get what you paid for right?

My fish have been sitting in a 100g Rubbermaid trough for two years now. Time for them to move into their new home.

 

[bmkj02]

couple more

 

[RocketEngineer]

I would run the 1.5" plumbing as high as it would go and then branch off the top most line for the 3/4" outlets. The inlet to the seaswirls should be level with or below this branch point so that when the 3/4" outlets suck air (because they are at the water surface), they break the siphon for the entire return manifold and allow the water in the seaswirls to drain back into the tank.

Don't use check valves in a marine system. Because things grow on almost every surface in our systems, you are likely to get a sponge or feather duster growing inside the valve and then it won't seal when you need it. The best approach is to use fail safe designs like what I described above. Its hard to block all the outlets at once.

Different question: How much water is in your system when you start the pump? I leave only about 1" of extra space in my sump when everything is off.

 

[bmkj02]

So you are saying I should have the return coming out of the sea swirl loop up and then down to help it break siphon inside of 90 degrees down like it is now?

I have to keep a lot of water out cause when power shuts down it will over flow back down. 1" extra space is impossible for me. I have to have about 8" or more.

 

[RocketEngineer]

If you need 8" your returns are set up wrong.

The problem as I see it is that you have the return manifold under the tank. Instead, you want the return manifold ABOVE the tank. In fact you want it even with the unions that connect the seaswirls to the rest of the plumbing. If you have all your returns exiting a common pipe which is located above the rim of the tank and you keep the standard outlets near the water surface, the regular returns will suck air in as soon as the return pump shuts off. Because they pull air so fast, they allow the manifold to fill with air and the water to drain therefore minimizing how much water gets siphoned out of the tank and into the sump.

Does that make sense?