Why is chlrorine level so low even with LQ?


LifeTime Supporter
Jun 23, 2011
Hampton Roads area, VA
Hi all,

I installed the LQ a few weeks ago. All seemed to be fine for a while with the flow meter of the LQ set to 3ish (my FC would be about 4) but now when I test my water my chlrorine level is very low. Please see my numbers below:

FC: .5
CC: 0
TC: .5
pH: 7.8
TA: 80
CH: 60
CYA: 20

My thought is that with my CYA being so low the LQ can't keep up with the sun. But at the same time I don't understand why it's not keeping up considering the constant feeding it pumps out. Am I off base? Do I need to raise my CYA? Is there something else happening here?

There's a couple of additional issues/questions I have that may or may not be related so I'm going to put it here just in case. If it belongs somewhere else please let me know and I'll repost it there. Read on.

First: anyone have any other thoughts about the test results? I think my TA and CH are too low, but I'm getting conflicting information even from within the TFP site so I'd be grateful for any opinions. Also, I'm having a helluva time getting my pH to stay around 7.5. This may be related to the airation that I think is going on in my next issue.

Next issue: About 2 weeks ago I made a terrible mistake by forgetting to put my multiport back on Filter after setting it Waste :oops: . It essentially ran for about 6 hours after it had drained enough water to drop it below the skimmer. I don't know if it's related, but it SEEMS as though since around that time I began noticing a significant amount of bubbles coming out of the return closest to the pump and the port used for the Polaris. Oddly, the return at the far end of the pool is behaving normally. What is going on?!?

Thanks for the help.


LifeTime Supporter
TFP Expert
Jan 6, 2010
San Dimas, CA (LA County)
My guess is that you are correct about low CYA causing FC to disappear too fast. It didn't help that you emptied out a bunch of CYA by draining the pool. Raise it.

TA will come down if you keep adjusting pH. pH rise will also slow down as TA gets lower. Deal with pH when it needs it and ignore TA.

CH is fine for a vinyl pool. You don't need to worry about eroding the plaster

I'd see if you have air trapped in the filter first. Then look for sources of air leaks, like the pump strainer gasket. If the pump got real hot running dry, you might have a drain plug that worked loose. Or an impeller seal that got worn. That one should be obvious - it will leak around the pump/motor junction, or maybe just squirt when the motor starts.