No air flow at 40 psi. Being a degreed Mechanical Engineer and wanting to solve the problem, I increased the air pressure to 80 psi.
I love it! Just use a bigger hammer!
If you attached a three way valve at an accessible position, you could make an access port that would allow you to blow the lines out each year with needing to call your chiropractor. If you got real fancy, you could attach it to an onboard compressor, blow out the lines while you're still in the water.