HOB overflow box help

Don't, whatever you do, put a ball valve on your overflow box drain line. If you were to ever get a snail or something else in there that slows down flow, it would flood your tank. Very dangerous. Really, this is only okay to do if you have a herbie setup, as outlined here: YouTube - ULTRA QUIET REEF TANK .

This can be done with a HOB overflow, but requires an eshopps PF-1000 or higher, or a dual drain CPR model. I just converted from my PF-300 to a PF-1000 for this purpose. I still use that DIY sump pump kill switch that I posted above incase I ever had a u-tube siphon failure (which, incidently I have had a few extra large snails get in there that slowed down flow enough that my overflow box coulnd't keep up with the return pump anymore..).


In your case I'd throttle back the sump pump down to half flow, or even slower, and turn it on. If the sump's watever level is going down and the overflow isn't starting up yet, it sounds like you need to just add some more to the display tank (in other words the sump is getting rid of water before it's able to get high enough to pass through the overflow and make its way back to the sump).

If everthing is working, throttle up the return pump until the overbox can't keep up and then throttle it back down a bit to allow for natural variations in flow rates.

ALSO, a way to increase flow from the overflow box is to have a larger delta between the water level in the tank and the water level in the outer drain box. This can be accomplished by raising the inner skimmer box a bit if it's too low.

Let me know how that goes.

 

well you could close it off a little to restrict water flow going in to your sump. or open it all the way for more water flow.

 

Oh ok. Yeah but the problem i'm having is that the pump is too fast. The Overflow is actually the one that can't keep up.

 

Another technique is to drill a small hole on your return about 1/2" below the water line, then as the water flows back down the return (in the event the ball valve fails) once the water level hits the hole it will suck air and break the syphon. Its just a poor mans back up to the ball valve. Or in my case a house renters back up, for what I would get charged for damage I want all the backups I can get.

 

Please, DON'T do this. Did you try any of the other suggestions?