air bubbles at low pump speed but not at high speed

[rhthompson]

when running pump at low speed there are air bubbles coming out of returns, but no bubbles at high speed. Why is this? Looking through the transparent lid of the pump body, it looks almost full of water at high speed, but only half full at low speed. I guess it takes the pump less effort to pull air than to pull water, but i would think it would pull air both at high and low speed. For what its worth, i suspect the air might be entering the system through old gate valves between the returns and the pump.

 

[duraleigh]

I believe your performance is normal. It is above my pay grade to clearly explain but perhaps mas985 or others can.

 

[rhthompson]

maybe at low speed there is more air entering at the skimmer weir?

 

[mknauss]

Clean and lubricate the pump basket lid gasket. See if that assists.

 

[Jimrahbe]

rh,

Do you have a saltwater pool?

Are the bubbles coming from your returns like Champane bubbles or large bubbles?

The faster the pump runs the more vacuum there is under the pump lid and the harder it is sucked down against pump body. So, lubricating the pump lid O-Ring, as Marty recommends, makes a lot of sense.

Thanks,

Jim R.

 

[rhthompson]

rh,

Do you have a saltwater pool?

Are the bubbles coming from your returns like Champane bubbles or large bubbles?

The faster the pump runs the more vacuum there is under the pump lid and the harder it is sucked down against pump body. So, lubricating the pump lid O-Ring, as Marty recommends, makes a lot of sense.

Thanks,

Jim R.

not saltwater

bubbles were about half inch diameter. I have increased the "slow" motor speed from 1600 to 2100 and it makes bubbles smaller and less numerous.

i have cleaned and relubed the pump lid meticulously and see no difference. I have used regular old magic lube -- should i use magic lube 2 instead?

one concern with all the bubbling is that it seems to deplete total alkalinity. If i have to just keep adding baking soda, will i eventually have sodium overdose?

thanks

 

[mknauss]

You have a suction side air leak. The easiest fix was lubing the gasket. If that does not work, you have to keep searching.

Bubbles do not lower alkalinity. Adding acid lowers alkalinity.