Help me with my HOB overflow!!

GOT IT! I just threw an undergravel strainer cap and a about an inch of 3/4 inch tubing on the end of the overflow return and everything leveled out. It looks better than a valve too .

One more question-- I noticed that when the PH is turned off it will automatically siphon the water from my main tank to my fuge. This is going to really suck when the power goes out one of these days. Anyone know how to avoid this?

 

you need to put a hole in your return line just below the water level in your main tank. . . so when the power goes off it will break the siphon

 

Even with the siphon break there will still be some drainage. I never fill my sump more than three quarters full. Once you have your hole drilled, simulate a power outage and see where your levels need to be kept in your fuge. I have a high and low mark on mine.

 

......and by the way, good job.

 

Thanks for the help everyone

Will this work the same way for my overflow if I just drill a hole right below the water line on the J-tube?

 

DON'T DO IT!

 

You can raise/lower the HOB Overflow to get the desired flow rate to the fuge. The return pump is what controls the flow rate back to the tank. Putting a ballvalve on the return line allows you to control that flow (I would not want 400+ gph flow through a 10 gallon fuge).

Example:
Shut the return pump off. As the water flows out of the tank (into the fuge), the level (in the tank) will go down a little. This will cause the flow to the fuge to decrease. It will keep decreasing until it reaches the bottom of the grooves that are cut out in the overflow. At this point the flow will be zero. Turn on the return pump. Water will start flowing back into the tank from the fuge. As the water level increases (in the tank, not the fuge), it will begin to flow back through the overflow box again (once it gets higher than the cutouts in the overflow box). As the water level continues to rise, the rate of flow through the overflow box (and into the fuge) will continue to increase. The water level in the fuge will go down until the system reaches a balance. So, the return pump and overflow box flow rates need to be matched. This is accomplished with a ballvalve on the return line and by raising/lowering the overflow box. You can have a slight mismatch on the max flow rates of the overflow box and return pump, as the ballvalve and height of the overflow box will be used to get it correct. My sump/fuge has a 300 gph overflow with a 190 gph return pump (return pump rating at 3.5 feet of head). The return ballvalve is wide open. The overflow has a ballvalve on it, and this is slightly closed (just enough to stop the very loud gurgling noise that occurs if the ballvalve is wide open). As you can see the 300 gph (overflow rating) is larger than the 190 gph (return pump rating), but it doesn't matter. The height of my overflow box (in the tank) is set so that the rates are equal (only about 2/3 of the grooved part is under water giving about 200 gph flow).

I hope that made sense.

 

NO...NOT THERE!!!. As above here, in the return line.

 

OMG, that's right, it's a fuge, not a sump. I have 600 GPHgoing through my 15 gallon sump but yeah, a fuge is a different story. Thank you Reeron.

 

......And also, what is the maximum recommended flow through a fuge? I know it is not very fast. Mine is going to divided into the standard three compartments with the fuge on the far end fed by a split (that is regulated) from the overflow.