Return pump too strong?

[SAtiger]

I have a 29g tank w/ a 30g tank set up as a sump. I am using a Mag 7 (700gph) as a return pump w/ a 9 ft hose. The sump sits about 3 1/2 below the tank. I'm using a CPR CS50 hang-on overflow rated at 300gph. Is this pump too strong? It seems like my overflow can't keep up and I'm afraid of my tank overflowing. Any suggestions?

[discuspro]

Don't take my word for it but maybe putting a valve after the output on the pump will help reduce the output flow volume. Don't do this until someone else says it'll be okay, I don't want to burn out your pump.

[SAtiger]

I'm thinking I should add a ball valve to the return plumbing. Anyone know the best place to get one? Home Depot, Lowe's, other?

[Ram_Puppy]

A gate valve would be better, but they don't seem to be easily available to the average guy (at least made of PVC they don't.)

I would add a ball valve. I don't think this will burn out your pump as it has no way of differentiating between the back pressure generated by a valve, and the pressure generated by head pressue.

[matt]

I have a 1" gate valve I can sell you; I ordered it for a skimmer but I need a bigger one. $12. It definitely will not hurt your pump to put either a gate velve or ball valve on the output; people do it all the time. A gate valve is better at regulating flow, ball valve is better at withstanding high pressure when closed. Either one would work in this case.

I got to tell you, though, I've heard many horror stories about the CPR overflows. Be prepared for a flood someday.

[SAtiger]

Yeah, I've heard some as well... I have the aqualifter pump on there which is "supposed" to take care of the siphon issues.

I have 3/4" tubing, so I'm not sure if that gate valve will fit properly. I was planning on going over to Lowe's later and looking at the gate/ball valves.

Anyone ever tried one of those SCWD Squid wavemaker things? I've read that those can turn excess flow into current?

[hoho19]

I have basically the same setup. I use a ball valve and it works magnificantly :)

[LoneStar]

You can use a ball valve or gate valve to help reduce the flow. Gate valve would be preferred because you can fine tune the amount of water coming out of them better than a ball valve. If I remember, the fittings on a mag7 are 1/2" so you will have a easier time finding a ball valve than a gate valve. With the pump at 3.5 to 4 feet below the main tank (plus the heighth of the main tank) you loose pumping power due to the head height. So a small cut back on a valve should work out fairly well on your tank.

As for the SCWD, I have never used one but from what I have heard, they cut back on the amount of water flow as compared to running it without one. The nice thing though is it will create random water movement, which is preferred.

What type of plumbing did you end up using? PVC, Spa Flex, flexible tubing??

[SAtiger]

I have some flexible tubing for the return. Just works best for a half-assed setup like mine :)

[SAtiger]

I have some flexible tubing for the return. Just works best for a half-assed setup like mine. :D I knew I forgot to ask you something when I got the pump. The valve seems to be a key oversight. :wacko

[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.