I bought a partially used Tunze 4 years ago. The pump was new but the rest was at least a year old. I paid $50 for it and have never had a problem. It has been the best $50 I've spent on this hobby so far.

Is anyone using the elos osmocontroller 2? :mrgreen:

Tunze Relay 12 v to 120 VAC
 

that uses the 12 V signal to activate a 110 VAC pump. This is good for large aquariums where the dinky pump they supply is not big enough. I found that my pump would burn out if some dirt or something got into the pump and jarred it. I put the pump in a filter sock and found it has lasted a lot longer (maybe my imagination). Nothing beats the optical sensor for reliably sensing the level IMO. Works even when it gets gummed up with gunk or invaded by bubbles from the skimmer output.

Tunze Relay 12 v to 120 VAC
 

If you don't like using the low voltage pump, you can get a Tunze relay that uses the 12 V signal to activate a 110 VAC pump. This is good for large aquariums where the dinky pump they supply is not big enough. I found that my pump would burn out if some dirt or something got into the pump and jarred it. I put the pump in a filter sock and found it has lasted a lot longer (maybe my imagination). Nothing beats the optical sensor for reliably sensing the level IMO. Works even when it gets gummed up with gunk or invaded by bubbles from the skimmer output.