ATO with auto water changes

[muls22]

I'm going to be setting up a new waterbox 190.5 and was planning on setting up an auto water change with a neptune dose and most likely set up a daily 3-4 gal turnover. I'm not sure if I need an ATO with that set up and if it will affect salinity levels. might be a dumb question but IDK

 

[Darren in Tacoma]

Your ATO is to replenish the evaporated water, which is fresh water, and will need to be done regardless of water changes. Without topping off for evaporation the water will gradually become saltier.