Auto top off using Salinity Control Module

[AnesthDoc]

Is it possible to regulate the auto top off water volume using the reading from the Salinity Control Module?
I have been using two part solution for Cal and Alk and recently discovered my tank salinity was high. I think having the auto top off regulate the fresh water volume based upon the pre-set salinity value would promote long term stability.

[89delta]

That's actually a good idea. Although i'd still use the float switches as a failsafe.

[lnevo]

You can there are a few doing just that. You basically need a routine to check the salinity and "set" the port being used for the ato function. However I wouldnt recommend it as probes can and do go bad and things could go out of whack.

However, with a good ATO salinity should stay pretty stable. Personally I would just set an alarm if it goes under a certain salinity and adjust accordingly. Only thing that could really make salinity drop significantly is skimmer mishap.

As far as your case with dosing that is increasing salinity... which you can only address by adding fresh water which your ATO already does so anything additional will throw off your ATO level which means ATO wouldn't kick back in until the water evaporates putting your salinity right back where it was!!!

You would have to "remove" water and replace with fresh to properly lower the salinity and then we're getting into auto water change territory with salinity adjustment

[AnesthDoc]

I think you are right, a faulty salinity probe would be a disaster with my suggested setup.
Thanks.

[lnevo]

I dont think that you can't or shouldnt do something like that, we can code around a lot of things, but its good to know what could go wrong to program around. The main thing that struck me with your issue though is that you would need a way to remove water (then let ato compensate for level) to correct for high salinity whereas low salinity could be corrected by adding salt water and waiting for evaporation to bring it back to normal.

Either way its completely doable and a bit on the advanced side, but certainly reasonable. Like I said there are a few people doing this today already.

[00Warpig00]

I have my ATO supply pump selected by salinity reading from the probe. If under x then ATO with SW of over X then ATO with RO/DI. I am NOT using the salinity measurement to tell the ATO when to STOP PUMPING. I am still using the ATO float switches for that. Just using the probe and switching back and forth from SW/RO in order to insure stability. I have had a few hiccups along the way but believe my ATO selection code is now ironed out.

Nick