Return pump too strong?

[LoneStar]

OOOPS >_<

The ball valve can help out too if you have to shut the pump down for some reason. If you don't want water siphoning back into the sump from the main tank, just close the valve. Works good when doing maintenance on the tank or sump. Since your using flexible tubing, you can get a ball valve with threaded ends rather than slip fittings. Then just get some barb adapters for you tubing and then hose clamps and you should be good to go. Just use thread sealant on while threading in the barb fittings.

[matt]

There's nothing wrong with using 3/4" tubing on your mag; in fact I believe they're "rated" using 1" tubing. There's no way a mag 7 will pump close to 700 gph at 3 ft head with 3/4" tubing and some elbows. If you use a sqwd, you'll lose lots of flow, which might work out perfect for your overflow; it's worth a try. Regarding the valve, you can get 1" thread by 3/4" hose barb fittings and use a 1" gate valve; it's actually probably a little better than a smaller one anyway. But, the ball valve will work fine and they're cheaper. The only thing about them is that often the valves are really hard to turn on and off; if you're connecting to flexible tube, you'll have to hold the valve steady. Best would be to attach the valve right to the pump; then put a barb on the other end of the valve. You can get a 1/2" X 3/4" (or 1") threaded bushing, put that on the pump, then the valve on it, then your barb. A slightly oversized valve will be easier to adjust, ball or gate.