Hi Brian
We recently purchased a couple of 500L Hot Grippatank Systems and one cold soon to be upgraded, should have done it years ago LOL!
Can't give exact temp at brush as requested but it's hot enough, works faultlessly, simple to operate, usual high Grippatank standard.
Crazy as it sounds but it appears to improve cleaning times/efficiency, no idea why, can't really explain it but it does.
Not the most scientific of answers but hope it helps
John