Mag 12 questions

[African_Fever]

I just picked up a mag 12 to run a 'sump' on a 200 gallon tank. The only thing is that the sump is actually above the tank (due to the way it's currently set up, this works best - long story). I'd like to run the Mag 12 externally, and am wondering if anyone else has done this without drilling the tank. I would use PVC to form a U into the tank with the pump sitting on the stand level with the bottom of the tank, and then also PVC the output up to the sump. When not under power, the syphon action would keep water in the pump itself, so restarting isn't an issue in any way. Other than leaking (which would be an issue with any external pump), does anyone see any issues with this setup?

Also, the instructions say to use 1.5" inner diameter piping/tubing for max flow rates, and yet the inlets and outlets are both only 3/4". Has anyone tried different sized pipes/tubes and found noticeably different flow rates with mag drive pumps? I was planning to use 1" PVC, but might go for 1.5" if it would noticeably increase the flow.

 

[Triton]

The set up doesn't sound too bad, but time could be your enemy here. I have a Mag 12 for my 200 gal and I use a 1 1/4 inch line (1in i.D.) coming in and 1inch (3/4in i.d.)coming out. I keep my pump submerged in a 50 gal sump below my tank.

The reason I say time may be your enemy is because it would be best to have some kind of filter on the suction side before it gets to the pump. As things change over time, the filter will clog up and possibly lower suction flow. As the flow lowers, it may come to a point where a bubble will form at the highest bend in the pipe. These air bubbles will grow until it breaks the syphon and your water pump becomes an air pump.

The same could be true when the water level changes, regardless of a filter, it will cause suction flow to change. As mentioned before, this could lead to air bubbles forming and so on and so on.

Also, if the dischage piping is submerged underwater in the sump, it could reverse syphon into the main tank if power is lost to the pump. This would possibly cause you to overflow your main tank.

Lastly, the Mag 12 shoots out a lot of water! I did not actually measure the differences in flow when I did this, but having the bigger pipe on the suction helped. I noticed slightly more flow with a 1 1/4 on the suction vs. 1in. I didn't notice the same change when I used 1 1/4 on the discharge.

Hope this helps!

 

[CHOMPERS]

You should reconsider putting it in the tank, especially since you are from Canada. The heat from the pump will help lower the load from the heaters.

If it absolutely has to run external, your idea will work fine. Just add a tee above the pump's suction side at the top of the tank and then add a female threaded fitting and a threaded plug. You will need to use the threaded plug to prime it the first time you start it up. There after, it will clear out any stray air in the system on its own.

 

[African_Fever]

The main reason I didn't want to run the pump in the tank itself if because the tank is a ray tank with sand, and the rays blow the sand absolutely everywhere. I was worried the 'prefilter' on the pump itself wouldn't be enough to stop sand from getting into the pump and causing havoc there. By having the pump externally, I was planning on having the intake about halfway up the side of the tank rather than on the bottom to cut down on the amount of sand. But now that I think about it, it would probably be almost as easy to have a 90 off the pump itself and raise the intake to mid tank.

 

[CHOMPERS]

That's a good idea. Add a Tee to the pipe to split the intake. The Tee will prevent entrapment if a ray gets sucked to the intake (it will allow the ray to escape the suction).