Overflow Question

[intarsiabox]

I have just set up my first tank that has built in overflows. It is a 52g tank with overflows in each corner and a 1" Durso stand pipe in each. It empties into a 20g sump. Every now and then only one of the overflows seems to fill up more than usual and then empties out really fast causing a flushing sound. It will do this once or twice and then stop for a few hours. I have a Mag9.5 return pump going into dual 1/2" loc-line returns. I had the pump running at full discharge for a bit but turned it down by 1/3 until all micro bubbles stopped coming into the tank. My problem seemed to happen more often when the return was at full discharge.

Do I need a bigger air hole in the top of my Durso? Should I dial the return pump down more? Any ideas would be great!

Thank-you!

[banditpowdercoat]

Sounds like the air hole. Either needs to be a little larger, or it's getting covered with salt creep?

[intarsiabox]

Maybe I'll try enlarging the hole a bit. It's not salt creep as I just finished getting my salinity to 35ppt today (only added water yesterday) so I have a month or so to play with it.

[Borderjumper]

I have duel overflows on my tank and one or the other will do that if I have the end of the pipe that emptys into the sump totally underwater. I cut a bit of a slot out of the pipe and have the top of the slot a little above the surface and that seemed to sure it

[intarsiabox]

Actually both of my discharges are under water in the sump. I opened up the air hole to 1/8" and so far so good. I guess I'll have to look at putting my hoses above the water but won't this be a lot noisier?

[intarsiabox]

The one overflow is still making that flushing sound every hour or so. I drilled a hole in the line above the water in the sump see how this goes. I figure the other overflow isn't doing this because the line travels all the way across the tank to empty into the sump so it has more head pressure.