I promised a link to the thermostatic mixer valve I have, but I could only find used ones on Ebay. I'm guessing they have been discontinued.

If you search Thermostatic MIXER valve, there's plenty out there, but double check the minimum temperature before you purchase. Most start at 30 degrees Celsius (86 degrees fahrenheit) which in most cases would probably be fine for 50% or below water changes but there are ones out there which start at 25 degrees Celsius (77 degrees fahrenheit).

merch store:
https://geordie-scaper-apparel.teemil...

Seachem info:
https://www.seachem.com/

All music from:
www.epidemicsound.com