When I got my tub I also got a new ozonator. with the exception of when I first got it when i was running the pump on low the I was getting no bubbles constantly coming up which means no ozone. Today I opened the spa up to figure out the issue.
Let me try and explain as best as I can.
After the tube comes out of the ozonator it goes through a check valve and then a heartford loop near the top of the tub. The tube then goes through an adapter where it goes into a slightly larger tube. This tube runs into a t-valve. If you go through the T you end up at the ozone jet where it meets up with a water jet thus creating the venturi.
Now the Other side of the T has a pipe running up to the built in ice bucket in the spa. The ice bucket has an air jet in the bottom which when water gets in the ice bucket, the jet through venturi sucks the water out of the ice bucket. Okay so hopefully you are following me....
To fix my lack of bubbles problem I replaced the check valve . the result was if I ran the pump on high and then put it to low I would get bubbles. If I let the tub sit for a few minutes then put it on low I got no bubbles.
i drew the following conclusion. What was happening when the pump stopped, water was coming backwards out of the spa into the tube where the ice bucket is and also a little in the tub going towards the ozonator. (before the Hartford loop) When the pump was on low, the venturi was not strong enough to push the water out of the tubes to inject air. So the water was blocking the bubbles.
When the pump was on high it would push the water out of the tubes and start the bubbles, at that point if I switched to low asap the water would not be in the tubes and I would get the bubbles.
The remedy..> Guys this is where I am not sure if I did the right thing. The tub coming out of the ice bucket was below the water line. Once out of the ice bucket I zip tied the pipe higher in the spa so it is above the water line. This seems to have solved the problem. Does this make sense?
I was thinking the T valve should have a check valve on it but I am not sure.
Please comment on if this is a good solution