water drain problems

[aaron]

I recently drilled the back of my nano reef tank and fitted a 3/4 inch bulk head hoping to increase tank volume by adding a sump. However I am having real problems getting the water to exit the tank fast enough. The tube to the sump is not full of water, just a thin coating on the walls. Does anyone know of this problem and more importantly have a solution?
Even the smallest pump causes the tank to overflow.

 

[Barnacle_Blenny]

Just reduce the rate of the return pump or lower the bulkhead if it's up too high.

 

[bad coffee]

Aaron,

Is your output drain blocked or kinked, also, does the hose go above the water line of your tank? it sounds like the bulkhead is too high, and maybe you have the output hose raised up above the top waterline.

BC

 

[cali_reef]

you will not have a lot of flow with a 3/4 inch bulkhead, the surface area of that is less than 1/2 inch. How low from the top edge of the tank do you have have the bulkhead? do you have a strainer on that bulkhead?

 

[aaron]

The bulkhead is about three inches off the top of the tank, no kinks or anything but it has an elbow in the tank so that the return water is skimmed off the top inch of the tank. If it were much lower I would end up with the tank draining out and the sump overflowing if there was a blackout.
I have reduced the rate of the return pump but it is now so pathetic that i am hardly getting any circulation.

 

[cali_reef]

Do you have a picture of the elbow? You can try putting a 2"x3/4" bushing and a short piece of 2" PVC on top of it. I have the same setup but I have 1 inch bulkhead and the hole is drilled further down than yours. This will increase the area\size the water can drain from, kind of like a funnel effect.