CLS Pump Question

[reef_noob]

Well, I built a CLS last night based on this model, http://www.melevsreef.com/closedloop.html
Thanks Wharyat for the link. It went together in about 2 hrs (still have to glue it)

I used 3/4" thin wall pvc, like melev, but I was wondering whether I could use a mag 9.5 on this. Melev says he is using a mag 7, which has 1/2" connectors, but the mag 9.5 has 3/4" cobnnectors, so I wouldn't have to step down. Also, I'd assume that the flow would be better with a 9.5. My concern is that the pump may be too restricted by the 3/4" tubing. I'd rather not stress out the pump, particularly if there isn't going to be a significant gph increase by using it. Any thoughts?

[Jasontkd]

with the 3/4 in fittings on the mag 9.5, I would personally use 1 inch pvc. howeve, I think it could still be done, because no matter what size pvc you use, you still have to push the water through the smaller fittings on the SCWD. I have the Mag 7 with the SCWD CLS just like that on my 20 gallon and love it. I can't keep anything that needs really high flow, but I guess it all depends on what you are keeping and the size of your tank. if your tank isn't that large, and you don't need a lot of flow for your corals, stick with the mag 7. my 2 cents anyhow.

[BuckWheat]

You would want to keep the 3/4" all the way because the squids produce a considerable loss as it is, you shold be just fine.

[reef_noob]

Well, just finished hooking the cls up. It's 3/4" tubing w/a mag 9.5. It seemed to flow well in a bathtub test, but I'll report back on the flow once I get it mounted in the tank. Since my tank is only 36" I think it should be enough flow but I might step down the outputs to increase velocity. we'll see.

[reef_noob]

I got the cls running today.
Originally I had built it with two output on either side. As soon as I started running it, however, I realized that the pump just could not drive four outlest with any reasonable velocity. Kicking it down to one outlet really helped. The flow is plenty for a 36" tank and the cls runs smoothly. The only issue is that it seems to occasionally draw some air from somewhere. I also seem to have a minor cavitation sound in the pump, this is probably because of the air leak. I can't tell if it is from the intake or one of the unglued joints. I left the upper joints unglued so that I would have more freedom of direction but I may have to glue some more of the joints. I'm going to run it for a while and see what happens.

[Doug1]

Chris you will want to glue all the joints on the intake side so you dont suck air there, it can lead to premature impellor failure

[reef_noob]

Thanks, I figured out that the air was coming in from the intake because the holes were too close to the surface. I lowered the intake which has fixed the significant cavitation, but I will go ahead and glue the intake as well.