Question About ATO Systems

[gabew]

I've been looking at various Auto Top off systems to set up but I have been wondering about if they actually add water when it evaporates of just when the water level goes down. If they just refill the tank with fresh water as the water goes down then this replaces evaporated water and doesn't take into account salt water slashing/spilling out. In that case wouldn't the tank get slowly fresher as salt water comes out with fresh to replace it? However if that actually measure the salinity and add water as it goes up this would only replace evaporated water in which case you would have to manually fill up the tank every once in a while to replace the splashed/split water.

So how do they work or are there models of both types? Does it actually matter if it doesn't take into account splash is the change any problem at all. And finally is there any specific model you would suggest?

 

[PbReefer]

ATO's are set up to refill water from evaporation. you really shouldnt have water splashing out of the tank.

 

[torero500]

Yes, with auto top off your tank does get slightly fresher over time, but I've measured it over the course of a week and it's hardly noticeable. You're much better off having the salinity stability and one less thing to do, then worry about diluting your water too much. At water change time you can always add a touch more saltwater than you take out to help even it up again.

And the best unit hands down in the Tunzo Osmolator. Has a double sensor system, runs absolutely rock solid, never fails, and it is probably the best thing about my whole setup.

 

[mthomp]

wait what? umm when water evaporates your salt does not go with it, so how does adding fresh water to overly salty water make it fresher over time? IM sorry torero but i do not think that is the case at all.

 

[Crawfish00]

If water evaporates the water level goes down..

 

[torero500]

Let me clarify, of course saltwater evaporating makes the remaining water more salty. I think what the OP is mentioning is an ATO system where that evaporated water is always being replaced by freshwater. That set up you basically have a net zero effect and the salinity remains constant.

But with daily maintance, hands in, salt creep, skimmer cleanout, filter sock cleaning, alot of different things export a little salt all the time. So if all you're doing is replacing the lost water with fresh water when the water level drops slightly in your sump, then the salinity slowly decreases over time because you're not repalcing the salt that got exported. My experience is less than a salinity point over a week, though.

 

[Clavius]

and the best unit hands down in the tunzo osmolator. Has a double sensor system, runs absolutely rock solid, never fails, and it is probably the best thing about my whole setup.

+1

 

[Original Fin]

Its not that salt never leaves your tank once you put it in, it just happens much more slowly than the water evaporates. That is where salt creep comes from, and it can be found many feet away from our tanks. It does not all come from splashing and micro bubbles bursting, it is in the air in the form of water vapor, through the process of evaporation, just in very minute quantities.