1 gallon/day evaporation on a 30 gallon is not a lot, IMO. I replaced almost 5 gal/day on my old 45; it was an open top tank with LOTS of circulation. There's nothing wrong with increasing your evaporation if you can. Probably the simplest option is to ditch the mag 5/sqwd set up (both not very good products anyway) and just use a couple of maxijets for circulation. Another very effective thing would be to get your lights up off the tank a few inches.

I've often thought about using ice cubes as top-off for cooling. If you could set up an ice maker with an R.O. filter, automatically dumping ice into your sump, sort of like icebergs melting, you'd have your own little polar eco-system; get a few tiny seals and penguins, maybe a miniature polar bear, some sort of aurora borealis display...