I have a 5 gallon Evo 5 reef (mostly zoa and a few other frags right now, No fish and just a few sexy shrimp). It's been set up for about 2 months now and generally doing well. Here's my problem: The tank is open-top and I bought an ATO that works well in the interest of maintaining very stable salinity in such a small tank. But, especially when I feed, my (old fashioned) limewood-powered skimmer tends to remove up to two cups of murky skimmate overnight. The ATO keeps the water level where it should be which causes the specific gravity to drop up to a couple points. I then have to mix up a cup of very high-salinity salt water and slowly add it to the tank (back chambers) while I keep checking the specific. So the whole process causes some instability in the system and can be a time-consuming hassle. I'd really appreciate any suggestions.