Alien;

I had a good set up on my nano for KW. To make one you need the following stuff:

1. a 1 gallon glass jug,
2. a 2 holed stopper for the jug,
3. 2 pieces of 7mm pyrex pipe, 1 is 2" long, the other goes to the bottom of the jug from just out the top of the stopper.
4. several feet of "tygon" tubing (1/4" I.D.) to fit over the pyrex pipe; you can use plain vinyl, but the tygon is better
5. a 30ml aspirator, you'll just be using the outer shell. Mke sure the tubing can fit over the spout on the aspirator.

Anyhow, you can get this stuff at Analytical Science supply. Once you get it, you'll set up a gravity feed auto top off for your wet dry; the mixed KW replaces all your evaporation. If you want to go for it, get the stuff and I'll re post with instructions for making it. (Don't have time right now) It's easy, real cheap, and it works great. I used one of these for 2 years on my nano and it never screwed up; kept specific gravity and CA/Alk levels stable; not easy in a nano.