Autotop off / Mag5 / Impeller failure

[Reefugee]

Hello,

My auto topoff consists of a brute 44G garbage can, a mag 5 pump and about 20 ft of 1/4 OD hose located out in my garage. The Mag 5 connected to about 2.5ft of 3/4" pvc pipe. The top of the pipe is T'ed where one side goes to the 1/4OD hose and the other side has a ball valve. The ball valve is left mostly open. When the pump comes on, some of the water is pumped through the 1/4 hose into my sump (located about 20 ft away). Most of the water goes out through the ball valve - which also helps aerate the water. This set up has been working great for about 1.5 years.

About 1.5 months ago, the impeller on the pump finally failed. Since then I have gone through 4 (yes four!) impellers. I have replaced the impeller cover as well. I can't figure out why so many of the impellers are failing. Any ideas? Are Mag impeller not good for constant on and off switching? Any suggestions on any other pumps that might be worth considering? Anyone have a submersible pump that might work for this function?

Thanks
Minh

 

[Underwaterparadise]

I have not had good lucking with constant on/off with mags. I broke 2 on a mag 12 and gave up! 4 in a month though WOW!

 

[Reefugee]

Yeah - they have a cheap little piece of plastic inside of them that broke off on each one of them. Can you recommend a different pump?

 

[matttaylor]

Any way to mod / glue the impeller together to prevent damage? If not then you may want to consider a pump with a single piece impeller design, although those will be mostly external.

 

[Underwaterparadise]

No personal expierence with something that needed to run 20' and turn on/off. Seio but not sure how to attach plumbing. Little giant and Quiet ones are good as well but not sure about the on/off.

 

[Reefugee]

Matt - I thought about gluing propeller as well. I don't know of any single piece impeller design.

 

[matttaylor]

Little giant external pumps use a one piece design. But it's external and i think they will have problems if the on off cycle is to close together. Making the impeller a single piece with superglue of a tiny bit of apoxy is probably your best bet. Just make sure the glue is evenly distributed around the impeller to avoid any balancing issues.

 

[kevin95695]

Maybe the backpressure is too much? Have you tried opening the ball valve more? Or maybe a wee pump would be better? A MAG5 to push water 20' through 1/4 tubing sounds like overkill. I understand the aeration factor, but even with the ball valve wide open I'd think water would find it's way through the 1/4 tubing.

 

[Reefugee]

Kevin,

I open the ball valve wide open. Then I slowly close it until a very slow stream of water flows through the 1/4 tubing. I was wondering if the back pressure was the problem - but I am surprise it would cause an impeller to break so fast. The last impeller lasted 1.5 days. The one before that lasted only 1 day. I don't want to pull new plumbing line since I eventually want to move the sump system out to the garage.

Minh

 

[MrMikeB]

Minh,

I do not think its sup much the back pressure but possibly the wear of turning those pumps on/off. Utility pumps are designed for constant operation, and the turning off/on does them no good. I would recommend looking into a 'soft' start/stop switch for the pump. Much like you get with a DC8 and an Neptune Systems controller. I had a MAG return on an older system and when I would feed the fish you could definitely tell it did not like the shut down/startup and would lurcha little each time. When I moved to the 'soft' style plugs ona DC8 with the AC3, that roughness all but disappeared.

 

[Reefugee]

Well - I tried epoxying the impeller so that it's one piece. It doesn't work. I think that on the mag pump, it needs the impeller to be two separate pieces. My guess is that this lets the impeller magnet get enough momentum to start the impeller blade.

Mike - do you know where i can get a soft start without spending alot of money?