New Pump

[alexwolf]

I have had it. I have a closed loop running off a Mag 18. I think all the plumbing is 3/4". I had a SCWD but i thought it cut the flow too much, to i took it off. Well, it has less flow NOW after i took it off! I can hardly feel any flow at all. It does hit a T on the back and come out 2 loc lines, which are split also. Can someone recommend a good pump for a closed loop? I really dont want to replumb, so hopefully something with 3/4 outlet.

[Gator]

alex i did the same thing with my return i put a "Y" on each side to get better distribution, but the Y just killed all of the preassure, i guaarantee you if you take all the y off and just use straight lock line it will blow your entire tank around, the y must do soething to eliminate all teh preassure


hope this helps
gator

[Brett Wilson]

There has got to be something wrong with that pump...... how much does it flow if you just stick the pump in the tank by itself? Maybe 3/4 is too much? I wouldn't think it is though.... I had a mag 5 on a 3/4 return and it provided some decent flow.

[alexwolf]

Gator, youre talking about the Y from the loc line right? Not the PVC T that splits hyalfway up?

[Gator]

i had a bluline 70 and with the y he is talking about it would not even blow your hand a ffot in front of it . i am willing to bet as soon as he takes off teh y he will be happy

[z28pwr]

First off, try to never use Tee's, you can use a PVC Y instead.

The T is killing the pressure, the pump does not have enough pressure to push out threw (2) 3/4" hoses, it was designed to use a single 3/4 inch not two.

If you must have (2) outputs then either reduce the T output down to 1/2 an inch and leave the input at 3/4" or as said previously take the T out and simply use one output.

You can also replace the T with a Y and reduce the ouput down to 1/2" an Inch.

You're asking way too much from the pump by expecting it to give you good pressure through (2) 3/4" lines that were fed by (1) 3/4 line. If you insist on running (2) 3/4" lines you will need a bigger pump like a Mag 36 or you will need to run (2) pumps. I don't think you need such a big pump, you just have the wrong plumbing.

[Brett Wilson]

ahhh didn't read closely enough to catch the part about the T....

[JimD]

I never hard plumb closed loops for that reason, I always use nylon flex hose and make gentle radiuses where the tubing bends. Im using a Mag 12 and a scwd on my main tank and it works better than great. Ill be installing a Mag 3 closed loop with a scwd on my 12 gallon nano soon, soft plumbed... 90 degree elbows Y's and T's will greatly reduce output, and the back pressure cant be good for the pump.

[matt]

Pumping into 2 3/4" lines from a single 3/4" line halves the pressure on the pump, by the way, it doesn't increase it. More diameter of flow=less pressure. Maybe you're thinking of velocity; as the diameter goes up, for a given flow in gph, the speed of the water will decrease. If there's a constriction, it's at the single 3/4" line.

Alex, mag pumps do not do well under pressure. But, it does sound like there mght be something wrong with your pump, or a blockage somewhere. If you want to tee into 2 3/4" lines, I suggest you feed those with a 1" line, use a 1" tee, and simply bush the outputs to 3/4". This will cut down your friction a lot. The tee does addd some friction, which maybe a Y would help with, but you can do a similar thing just by making the tee bigger.

[TAXMAN]

Alex.

When you had the SQWD did you have the lines supplying the SQWD in flexible tubing or PVC? Sounds like with your problem it was in tubing. As far as flow and pressure is concerned, Matt is correct. The SQWD will flow more Pressure because you are flowing the water through 1 side at a time. If you flow through 2 outlets of the same size that the SQWD outlets were you will get approx. half the velocity. But the flow would remain the same. If you have plumbed it all in PVC since you removed the SQWD, this will account for some of the problems. You will have multiple problems.

1. Every 90, 45 and T in the pipe including the pipe length itself will have friction loss factor which will cause a loss of flow.

2. Moving water though 2 outlets versous 1 of the same size will decrease the velocity but not amount of flow.

So my suggestion is to use all flexable tubing and use a Y connector instead of the T. This will help to get the flow back up. Then you can decrease the outlet size in the tank to get the velocity up if needed. I dont know how much head pressure your pump can work against before it drops flow rapidly.

Maybe this will help.

[dan]

ya !!!! IWAKI now your talking. go with a 30 or 40. that will move some water.