Fishboy9227
New member
If I have a overflow box that is rated up to 600pgh and the pump in the sump in only 300gph, will it be a problem that i am only moving half as much water?
-Fishboy
-Fishboy
Pump and Overflow box
- Thread starter Fishboy9227
- Start date
Toddrtrex
Premium Member
The pump can be at a lower rating then the overflow box (( in fact it should be )). The only issue that could come up is if the pump is too slow --- any bubbles that accumulate in the U-tube won't be cleared out. So you will have to keep an eye on that. Thinking that you might be at the lower level, so I would watch it.
StephenInVa
New member
It won't be a problem but I've read that you need at least 200 gph in a u tube overflow to clear the bubbles. With pumps you have to take considerations like friction loss and head height of the pump. Things like the max head height of the pump and flow at that height. A pump that's just pushing water straight out of the discharge won't push as much water at an elevation. Nor will it put out as much flow after passing through a length of tubing. If you're not getting enough flow through the u tube you get bubbles which will eventually turn into a larger bubble that could break the siphon.
When I set up my 30 gallon I used a 300 gph pump and a 300 gph over flow. It's a little over 3 vertical feet between the pump and discharge on the tank. I was constantly (2-3 times per day) having to hold my hand over the over flow discharge in the sump to build up water in the tank to clear the bubble that developed in the u tube. I upgraded to a 475 gph pump that puts out 315 gph at a 3 foot head and haven't had a problem since. I checked the flow with a meter and after friction loss and such I'm getting 270 gph. If I had to do it all over again I'd more than likely get a larger pump and add a ball valve.
If you're in the market for a new pump I'd highly recommend the new Maxi-Jet utility pumps. Attractive, low wattage, small, and lots of power.
When I set up my 30 gallon I used a 300 gph pump and a 300 gph over flow. It's a little over 3 vertical feet between the pump and discharge on the tank. I was constantly (2-3 times per day) having to hold my hand over the over flow discharge in the sump to build up water in the tank to clear the bubble that developed in the u tube. I upgraded to a 475 gph pump that puts out 315 gph at a 3 foot head and haven't had a problem since. I checked the flow with a meter and after friction loss and such I'm getting 270 gph. If I had to do it all over again I'd more than likely get a larger pump and add a ball valve.
If you're in the market for a new pump I'd highly recommend the new Maxi-Jet utility pumps. Attractive, low wattage, small, and lots of power.
