I built a DIY ultrasonic cleaner last year and love it as well. I think the US tank was about $100 and then I used a BBQ rotisserie motor and brackets to turn a spindle and plexiglass pucks as disc separators.
I use Triton X-100 as a detergent and Hepastat 256 as a surfactant, anti-static and anti-fungal (so your solution doesn't start to grow stuff). Plus some isopropyl alcohol and distilled water from the grocery store. There is a recipe online. I usually set the heat to 35 but unless I'm doing several batches, it never gets hotter than 32 - no problems. I do have a separate rinse tank with pure distilled water to wash off the detergent and stuff. They air-dry just fine but I did buy a little clip-on desk fan to speed it up.
It's amazing what it can do for both new and older records. It's noisy but worth it. If you decide to try the BBQ rotissery motor, I have a simple trick for getting a round spindle to fit in a square chuck (just took me 5 or 6 attempts to figure it out :-).
If you have the space, I highly recommend it.