you may need to set your thermostat higher than your desired temp to reach that in your tubs or on your heat tape.
I think i've got my thermostats set to about 96 sometimes (in the winter) now that the temps have stabalized as its gotten warmer its set to 93 i believe, the temps in the tubs are 92-90 on the hot side.
I've heard of some breeders having to set their thermostats to over 100 to get the desired temps in the tub, i think it has to do with how much heat tape you have.
I have 3 racks, animal platics economy plastic, a RBI and a hand made one (all bought second hand) and they are all great. The AP are almost indestructible, the RBI is super well made and the tubs slide great.