Sure you can use the exo-terra pad on there.. Hagen(exo-terra) is made by Calorique which makes the flexwatt. The only thing is, will the pad be large enough for the tub. How big is the tub? The 8x8's are only 8 watts and thats pretty low if your looking for a 90+ hot spot.. Also the dimmer is a very scary thing to me(anal retentive)..
-matt