Large bubbles in tank drain pipe

[jwc3]

I'm setting-up a 75 gallon reef tank with 20 gallon sump. The salt water is mixed and has been circulating for the last two or three days. I am planning to add live rock this weekend. Thanks to the great advice on this forum, everything is running smoothly, except for the trank drain pipe.

The problem: the drain pipe leading into the sump is full of huge bubles. The place in the sump where it dumps looks like a blender that's on 24/7. The water gurgles and churns, making a lot of nose. About every 10 seconds it sloshes so high that it splashes out over the top edge of the sump. (The sump is about half full.)

Any ideas how to remove (or at least reduce) the air bubbles to quiet this thing down?

 

[silent1]

not so sure but you could try
try lowering the pipe under the water level in the sump. If you have that sorta sump where it goes in straight. Check for any leaks aswell Or try cutting the ends at a diagonal direction this should reduce air intake into the pipe.

 

[Anonymous]

Stick a piece of airline tube in the standpipe this acts as a vent and works some time.
Andy

 

[jwc3]

try lowering the pipe under the water level in the sump.

Thanks, but the end of the drain tube is already under water. I'm using clear flexible tubing, so I can look at the water as it flows/falls through the tube -- the air is already in the water before it hits the sump.

 

[jwc3]

Stick a piece of airline tube in the standpipe this acts as a vent and works some time.
Andy

Based on the instuctions on the Druso web page, I drilled a small hole into the cap at the top of the standpipe. Do you think that hole will do the same thing as the airline tube you recommend? Or are you recommending something different?

At first the hole in the cap was too small, causing the water level in the overfow area to be too low. This created a waterfall effect that was quite loud. So, I drilled a slightly larger hole, and the water level in the overflow area rose, making the overflow much quieter.

 

[jwc3]

Are we allowed to answer our own questions around here?

I've managed a partial fix of the problem. The water was sloshing up over the edge fo the sump every 10 or 15 seconds. I realized that the drain hose from the tank was so long that it almost touched the bottom of the sump. I trimmed the drain hose so it is only 1 or 2 inches under water. That seems to have reduced or elimated the periodic sloshing by reducing back pressure.

However, I still have tons of bubbles from the drain hose. Since it seems that there's no easy way to prevent the bubbles, I'll have to focus my efforts and eliminating them after they are created. The best solution seems to build several baffles in the sump before the water reaches the main pump. Can I glue/caulk the baffles into place while there is still water in the sump? Is there a reef-save adhesive that will cure underwater?

 

[Juck]

If you raise the hose slightly out of the water, the bubbles in the hose should disappear.

 

[jwc3]

If you raise the hose slightly out of the water, the bubbles in the hose should disappear.

OK, just tried it. When I raise the hose out of the water, the resulting splash makes even larger bubbles than before.

Looks like I'll have to build a baffle system in the sump. Can I do that without draining the sump?