ATO for RO/DI AND Saltwater

So I bought an ATO to be used via air lines pushing the water up a line. I have RO/DI water in a 5 gallon water jug and saltwater(for water changes) in a 5 gallon bucket. I split the air line via a "Y" and the RO/DI top off works great, but trying to do the saltwater change today, for some reason it would not pump it up. I do have valves to close off the air line to the RO/DI water to maximize pressure, but the air line just inflates the bucket and can't seem to push up the saltwater.



I know this is kind of hard to understand, but I can't post pictures right now and I was hoping someone has done something similar.



Any help on how to ease the pain of water changes in a small tank would be great!