Tank Flow from Powerheads and Return Nozzles

[laverda]

I'm just going to leave it the way it is and gain flow with powerheads if necessary.

From thinking about the submerged return nozzles, as long as the nozzle is under water and the return line does not go up and out of the water, then even if siphon is broken, then water will drain through return line.

If I eventually bring my return line up and over the back of the tank, then I can drill right below water line and then I wont get a siphon or any draining back since it goes up.

Right now, my return nozzles are at the same height as the highest part of my return line, and that is all below the water line of the display tank, so it will drain to the highest point.

I could run the return line in the overflow above the height of the return nozzles and then do an upside down "U" to get to the bulkhead, but there isnt that much room in the overflow.

Is my thinking right on this?

A siphon break does exactly what the name says. Your thinking is correct. a siphon break will not stop water from flowing in you set up at all. You can't fight gravity. if both your returns are angled down a siphon break will stop the water flow a soon as it becomes exposed and the water is lower than any high point between it and the drain. IE until the water level reaches the bottom of the horizontal tube through your overflow box. if the output of all 4 nozzles is higher than that the water level will drop to that of the lowest nozzle. You need the curve the lock line up to the surface and back down and have a siphon break on each side between that point and your 90 degree fitting. You could make the high point inside the overflow box, but it may be hard to fit in the tight space. personally I always thought it was a dumb practice to put the returns through the front or side of the overflow. I prefer my returns to be as far as practical from the overflow. Other wise you sending a larger portion of the same water right back to the sump. You could just add an extension to bring your existing returns up and over t overflow to mid way down the back of your tank before turning down into the water. Then a siphon break will work very effectively.