Differences in MAG3, 5 and 7

[JWeb]

What makes these pumps different? (Other than the obvious answer that the 7 flows more than the 3!) I have 2 3s, a 5 and a 7 and the external dimensions are all the same (I believe the MAG2 fits this category, too). Do the mag-drive motors have different windings on the three pumps? Different impeller? A larger flow orifice or something? Can one modify a 3 to flow like a 7?

I'm sure if I took them apart, I could figure it out... but they are all running and serving a purpose right now... wish I thought to do this before I fired up the tank.

When looking at replacement parts, the 3/5 impeller is the same part number... the 7 is different... which leads me to believe that it isn't just the impeller that increases the flow.

Weird, wild stuff.

 

[JWeb]

Hmm... in looking on the Marinedepot website for an answer to this, I see that the MAG pumps aren't recommended for external use. Any comments on this? I am using the MAG7 for my closed-loop... and it's running behind the tank. Am I asking for trouble?

 

[NanoReefer]

They all run at different wattages, so I would guess that the copper windings are proportionaly differently. They would probably just fill the space with epoxy and use a standard size casing. I'm no electrical engineer, but some time in electo-mechanical assembly would make it a laymans guess.

 

[JWeb]

Since the impellers are the same on the MAG3 and 5 but they have different flows indicates you are probably right, Nano. I don't see myself chipping out any epoxy to add windings to the pack... so I'll just stamp them 3, 5 or 7 and move on.

Any advice on how to "harden" the pump to make it suitable for external use? I have thought about putting silicone around the pump cover since I understand this is where the leaks develop... that wouldn't be permanent and might help mitigate trouble. Comments?

 

[NanoReefer]

I have seen posts on RC, etc.. about them used externally and it appears that it is not recommended, although the manufacturer say otherwise. I would guess that lots of teflon and careful handling (the problem was cracking the housing along the threads) while assembling or disassembling for cleaning. I don't use any pumps externally so....

Someone here must use a mag externally, I am sure they will chime in.

Good luck.

 

[Jim Tansey]

I have a Mag3 on my Ca reactor externally mounted no problems. I always thought they could be used that way.

Jim

 

[dedfish]

I use a mag5 on my 20L externally. I think a lot of the leaking problems that you read about happen after the pump has been serviced. I had a mag7 that developed a leak after I cracked it open to make sure it was clean.