I just installed a new Intelliflo variable speed pump to replace my single speed. I've never had a pump that can run this slow before so I'm not sure if the air bubbles I'm seeing are normal or not. I've got the pump set up to run at 2500 RPM from 8:00am to 11:00am for the pool vac and then 1000 RPM from 11:00am to midnight for circulation. The pump is off from midnight to 8:00am. I have a spa that spills over into the 18000 gal pool and no other water features.
When the pump is running at 2500 RPM, I can see some small bubbles in the pump intake basket. When the pump runs at 1000 RPM, there is an air bubble about the size of a quarter in the basket and it just sits there at the top while the water flows through the basket. When the pump is running at 1000 RPM, I see grape size bubbles slowly rising from the return jet furthest from the pad and I can hear what sounds like trickling water from the return lines near the heater and chlorinator. If the pump has been running at 1000 RPM for awhile and then I bump it up to 2500, as soon as the RPM kicks up to 2500, a big burst of air comes out of the return jet closest to the pad for about 2 -3 seconds. After that, no more bubbles, except for tiny ones that I assume are coming from the chlorinator which is currently set at 50%. Can the chlorinator produce enough tiny bubbles that they get stuck in the lines at the low pressure of 1000 RPM and then get forced out when the high pressure of 2500 RPM kicks in?
My water level is perfect. My pump basket seal is new and on tight. My intake union is new with a tight seal. I don't know what else it could be. I'm thinking that this shouldn't be happening, but I've never had a variable speed pump before. Is this normal?