Potentially stupid overflow question.

In2deep

In2deep

AC Members
Jan 30, 2007
28
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Highland, CA (Moved on up to the east side)
HI.
I am sorry if this is a stupid question.

How much waterfall should be inside of my overflow?

I have a 90 gallon tank with 2 one inch bulkheads. My return is a soft plumbed Eheim 900gpm.

I know that having some waterfall inside of the overflow is important for surface skimming but how much is needed for surface skimming and aeration?

Here is the problem:
I can not get my tank to fill up.

I was running both overflows and then when it would not fill up I closed one off and raised the other standpipe (Stockman Standpipes). This just causes the overflow to fill to the point that there is no waterfall and then the waterlevel rises to where it is close to where it should be. (where there is no air space showing under the lip of the tank while looking at the front but still not as full as I would like)

Do I need a bigger pump?

I am frustrated I bought this tank and spent forever saving, buying parts and building the stand. I am wondering if maybe the teeth on the overflow are cut too low? GRRRRRRRR Please help if you can:sad:
 
I would suggest its down to an impbalance in the plumbing...A 1 inch overflow is rated at around 600gph..so, with your 900gph pump, two over flows are too much ( 1200gph ) and 1 over flow is not enough.

You only really need a couple of inches waterfall really..dont really see any need to have more. How wide are the teeth slots and how tall are the slots on the weir comb?

Niko
 
More info please before I make any recommendations, as a few things are a little unclear to me...
Is this a custom drilled tank, or a factory drilled tank?
Are the two overflows custom installed, or factory installed?

If this is a factory drilled tank with factory installed overflows, the problem should not be the pump. Water can only go down the drains as fast as it's pumped up from the sump, otherwise your sump would be overflowing.
 
The tank was made to the recomended specs by the manufacturer and LFS.

I keep thinking that I need to pump in more water. I am thinking that the water comes in too slowly so the water level in the tank stays at the bottom of the teeth on the overflow as the water comes in.

The only way to raise that waterlevel in the tank is to lift the standpipe higher.

I may be selling my brand new Eheim 900gph pump only run for 30 minutes in fresh tap water for a bargain price.
 
I would try a larger pump, something rated for 1500 to 1800 gal/hr at 0 ft. if your sump is in the standard location(under the tank, in the stand). You may or may not need a ball valve to slow the flow coming off the pump as to not keep emptying the sump(opposite problem, not enough water coming down through the overflows). Raise the standpipes to about 1 or 2" below the water surface, you don't have to have it crashing in the tower area. Make sure all breather holes are clean(open) too. I hope you can fix your dilemma here.
Matt
 
Here is a flow chart for the Eheim you probably have, you are roughly pumping roughly 600gph or a little less(enough for one overflow), when you figure in the head height. A larger pump should do the trick for you.

b3c31b22.gif

I hope this helps a little
Matt
 
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