This is my first post here so be gentle! I am building a concrete spa and I am confused about the blower and air control valves. Do you need air control valves with a blower? I do see that they are required with Venturi jets since the valves control the air admission. When additional air is pushed at the jets, what function would air control valves serve?

Brian

IMHO, an air blower is useless in a tub if you're plumbing it into the jets venturi plumbing. Just stick with the afc valves, the air blower isn't going to much, if any, additional "umph" to the jets. If you have a separate air injection system for the air blower, go for it.

Yes, I agree. Don't do this.
Unless you've got experience with requirements of blower air flow you'll have nothing but problems. The usual installation results in burned out blowers because not enough air flow is allowed to get to the jets because of the restricted plumbing design.

You'll hate the effect of blower air coming out of your jets anyway. If you want better action, install more jets, and a bigger pump.