ATO Advice for our Smaller Reef Aquariums

Science/G · Mar 2, 2025

So in my 30 gallon mixed reef I started out with I guess the gold standard which was a Tunze Osmolator. My sump is only 7 gallons and I was not happy as it dumped multiple cups of replacement water into my tank at a time. Not a big deal, as salinity shifts on reefs, but I wanted stability. I now use a dosing pump, set for 12 intervals daily. Salinity is rock solid stable. It will take a bit here and there to get it dialed in, but worth the effort I feel for those with aquariums on the smaller side.

exnisstech · Mar 2, 2025

I've always used an ATO regardless of tank size. I just added one of these to my IM 20 AIO. I have tunze, kamoer and JBJ units but this is a budget build so I went the Amazon route. It's only been running a couple of weeks but it's workings great. I have the optical sensor in the back chamber and when it cycles it only pumps for a second or two.

EDIT: your method will need tweaking as evaporation rates vary.

Tamberav · Mar 2, 2025

ATO made for nanos work differently. Usually a small slower pump and too long running protection is a shorter duration. I have had no problems using them in small tanks.

Tahoe61 · Mar 2, 2025

I have used Smart, Duetto and Tunze. The only reliable one has been Tunze Nano or a Cliscea gravity adapter ( I highly recommend) for Nanos.

ShaunMc · Mar 2, 2025

MrGisonni said:
So in my 30 gallon mixed reef I started out with I guess the gold standard which was a Tunze Osmolator. My sump is only 7 gallons and I was not happy as it dumped multiple cups of replacement water into my tank at a time. Not a big deal, as salinity shifts on reefs, but I wanted stability. I now use a dosing pump, set for 12 intervals daily. Salinity is rock solid stable. It will take a bit here and there to get it dialed in, but worth the effort I feel for those with aquariums on the smaller side.

This is not the Tunze nano correct? Which model? Sounds like you just need a smaller pump.