Reef Discussion

Rob

Member
Apr 26, 2012
743
424
Tunze Ato Pump -failed
I understand these pumps are cheap and really I do not expect years out of them so I have a couple of spares. So when my ATO pump failed last week I just got my spare and replaced it. Curiosity got the better of me so snapped it open today. Obviously has been running for quite some time like this as it only been out of the tank a couple of days.

tunze.JPG


I use three of these pumps, ATO and for AWC (drain & Fill). I always buy a couple if I do a sewatec order as they are something like AUD$20 but if there going to do this I may have to rethink. I have two new ones which ordered a few weeks ago, so I may just break another unit open just to see if other pumps are also doing this.

I really hope this is a once off, if you have one failed please crack it open (wearing goggles) and take a look.

EDIT... I have now decided that the blue end cap was not sealed properly against the body. I can see in the blue end cap that the piece that should of been glued against the white body also has that brown rusty puke on it.

wonder how much of this iron actually leached into the tank... ? hopefully not too much and it was contained.
 
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Buddy

Member
Mar 13, 2012
3,142
1,526
I have had a a tunze ATO pump fail too. I opened it up and it had a tiny bit of rust but nothing like that picture!
I had a tiny bit of the rust stain starting to come out where the blue plastic meets the white plastic.
 

Rob

Member
Apr 26, 2012
743
424
Yeah this one was on ato as well, no salt. I will however open up one of my salt water ones.

Im going to 3d print a cylindrical cap that fits over the wire onto the body. Maybe a few mm bigger than the body so i can 'pot' it with silicon
 
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Rob

Member
Apr 26, 2012
743
424
I am assuming the rust was contained within the body of the unit and not leaching out too much. Well that's what I would like to think. :eek

I had been chasing a weird earth loop for a long time. The only device I never disconnected was the low voltage ATO pump which in fact could of been earthing the tank through the 12VDC supply. I wish I would of tested the electrical installation between either of the 12VDC wires and the top off water, Although after saying all that from memory pure water is actually an insulator and is probably why the motor still ran.
 
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Rob

Member
Apr 26, 2012
743
424
I thought I should update this thread and comment on a new design which must of happened in the last few years. prior to this I had a number of failed pumps show signs of a lot of internal rust.

I see tunze has changed the design around the impeller which seems to seal the top of the motor shaft now and also seats better around the oring seal. I had another pump fail today (one of the newer designs installed 2015) and there is absolutely no signs of any rust. These pumps seem to be lasting me about 2 years on ATO and water changes as I run three of them in my tank. The two Water Change pumps do ~50 litres a week of salt water changes.