Hi, I’ve got one in my sump. It’s very simple to set up, and I wish I’d done it much sooner.
The little kit I got was about $100, it’s a magnetic “eye” to set your level, a small pump that goes in a reservoir of your choice, and a power adapter. FZ something from Amazon. I also have one from brs (see their YouTube channel for video tutorial) that I don’t like as much.
I’m using a 10g aquarium for reservoir because it’s what fits in the cabinet and I had it laying around, but I wish it were bigger. My system is a 142 rimless with 30g sump. I love about 3gallons every day to evaporation.
Make it easy on yourself to turn it on/off because you’ll need to do it at every WC. I use wifi outlets and an iPhone.
Now, cue the “if you were changing water daily you wouldn’t need one” reply, lol! I’m really glad I got mine.