Stand pipe question

[blueroof]

I have a 1200 gallon reef that has just recently been started up. The tank has 2 overflows that combine into a five inch line that goes to the sump. This line is underground and inacessible other than the cleanouts. The sump/refugium is a 500 gallon concrete tank that is below grade and some 50 feet from the tank. There is only 18 inches of drop and 50 feet of run.

The good news is there are zero bubbles that make it to the sump. The bad news is every few minutes a large bubble forces its way back to the tank. It pushes about 20 gallons of water back into the tank and then "explodes" its bubble back into the tank Then the water rushes down and the whole process starts again.

I have tried every variation of durso. When the bubble returns and the durso is in place it blasts water through the air hole hitting the ceiling 4 feet above the tank.

Any ideas?

 

[dsandfort]

Could you put a "burp" vent at one of the cleanouts?

 

[Mahlhavoc]

is your sump sealed? it sounds like you are getting negative pressure in the sump and then it lashes back out at you.


I would, however, like to know how you went about getting zero bubbles into your sump. do you have a drawing or a picture?

 

[blueroof]

I have considered a vent but I think I would need to get several feet higher the the surface of the tank. Not easily done since the construction is done. But possible.

My theory on no bubbles in the sump is that the length of the pipe (50 feet), the lack of a dramatic drop, (18 inches) and the large diameter of the pipe (5 inches).

The Top of the water level in the sump is 18 inches below the bottom of the tank. The sump however in 5 feet deep and the return is through the bottom.

 

[blueroof]

I have considered a vent but I think I would need to get several feet higher the the surface of the tank. Not easily done since the construction is done. But possible.

My theory on no bubbles in the sump is that the length of the pipe (50 feet), the lack of a dramatic drop, (18 inches) and the large diameter of the pipe (5 inches).

The Top of the water level in the sump is 18 inches below the bottom of the tank. The sump however in 5 feet deep and the return is through the bottom.

 

[marcrothschild]

So your drain line is submerged below 5 feet of water? If so, that is quite alot of pressure to overcome since your stand pipe is barely submerged. I think that the drain needs a vent comming out of the sump end just above the waterline. A "tee" fitting with a standpipe might work. Thats just my thinking... HTH