Auto Top off question...

[ner'T']

I've been doing a search on this site for a simple, (cheap!), autotop system. I currently just use a gallon container dripping kalk.

I need something a little more automated for when I leave the tank for multiple days.

Should I be looking at "autotopoff.com", or is there a better way to go? My tank is sumpless.

Thanks for any suggestions!