Dumb overflow question

[hdodd]

I have set up a new 125 with corner overflows. One corner drains straight down to the sump. Each over flow has a "u" shape at the top so water enters the upside down open part of the "u" and then spills over into the drain pipe. The problem is that the water level in the overflow moves up and down. The "u" has three holes in it, two on each side and one up on top with a short piece of tubing to pemit air. The noise created by this up and down action is rather loud. It only happens on the one overflow, the other is just fine. The tank is level as best I can tell after careful attempts to make it so. Thanks for the help.

[kaihonu82]

is the water entering the overflow not a consistent flow?

am i totally not understanding whats going on

[kgouso]

This is a guess, but it sounds like the overflows can't keep up with the pump (until one gets a siphon going)

Is the water level moving up past the air holes and then back down below...(repeat)

If so...when the water rises completly above the standpipe it creates a siphon and then will quickly drop the level. When the level gets below the air holes the siphon "breaks" and the overfolw slows down.

If one standpipe is higher than the other (even though the tank is level) the lower will get a siphon going before the other and will drop in level much faster than the other side.

[reefergeorge]

You just need to drill out the small hole ontop a little bigger. Air is getting traped in the U part. When the water goes down the air excapes the side holes, and the cycle begins again.

[reefergeorge]

If you want to get a little more custom. You can drill the top hole out to fit 1/4 inch tubing (like on an rodi) and put the micro ball valve on the end of that to control the amout of air. It seems to make mine a bit quieter also.

[hdodd]

Thanks for the help. I did enlarge the hole and the degree of movement up and down of the water slowed considerably. I will enlarge even further tomorrow and give a report. I also noted the siphon issue. I assume (note how dumb i am with this one) that the system is not designed to me one where the pump causes a complete watertight so to speak system. In other words there is supposed to be some air entering the system through the overflow devices??

[reefergeorge]

When you drill it out. You may have to find some tubing that will fit the new size to keep the noise down.

[hdodd]

I also have another thought. I have two overflows as stated. I ran one pvc straight down into the sump. The other comes over and then down. I.E. I have two pipes running into the sump with each running well down into the water some 4-6 inches. I, of course, get a lot of bubbles and turblence and noise. Is this the primary cause of the noise do you think and if I cut the pvc to just above water level will I just get less noise? Thanks again. Reef central people are the best.

[RobNJ]

how strong of a return pump are you running? You dont need to pump super high flow through a sump. Use a ball valve on your return and try slowing down your return pump.

[hdodd]

I have durso standpipes, finally figured that out. Have read several sites which have been helpful. Must have to play around with air flow. Will try the pump idea as well. Am using a blue line model 30 x.

[ccoral]

it all has to do with water flow. Try to change the diameter of the hole
www.dursostandpipes.com

[hdodd]

Solution found?? Keeping fingers crossed. Enlarged the air hole and fitted a "1/2" inch valve for irrigation systems. Adjusted valve and presto, sucking sounds gone. Great difference in the noise level. If I could just suppress sump sounds, would be a very happy camper. Thanks to all for the help, you were just great. H

[ljosh]

There are a few ways I have seen on here that are supposed to help with the sump noise