FC loss from Algae or Leaves


New member
May 21, 2010
Buffalo NY
How do you know if FC loss is from bugs and leaves getting into to the pool or from algae growing somewhere?

I have a 27' 54" above ground pool ~17,000 gallons, surrounded by trees on 3 sides. It gets ALOT of debris in it every day. It only gets 6 hours of full sun a day, 1 or 2 more hours of partial sun.

I am not sure if I am just paranoid or should really be concerned. How much FC loss is expected due to leaves and bugs getting into the pool?
If I have the pump running 24/7, I need to check the skimmer basket 3x per day to make sure its not plugged. On a windy day there can be alot of leaves and tiny tiny dirt in the pool.
At 10:30pm tonight I tested the FC it was 5.0, then added ~2.0 ppm, and will test again to confirm the amount added, then do an overnight FC loss.

Ever since I got my TFtestkit I have been losing 3-4ppm per day, but the CC is always < or = 0.5 ppm sometimes its even 0. I haven't done a proper overnight loss test because I can't beat the sun up, but will try to tomorrow.

Should I be worried about algae or could a large amount of leaves and bugs cause a loss of 1-2 ppm overnight?


Platinum Supporter
LifeTime Supporter
Jun 28, 2009
I would suggest you get it as clean as possible one night, then do an overnight loss test per the instructions in Pool School. If you lose more than 1 FC, seems like shocking is in order. Keep it at shock level until: a)you lose less than 1FC overnight; AND b)you have .5 or less CC; AND c)if you don't have an FAS-DPD tester, your pool water is clean and sparkly. I'm certainly no expert, but I've lurked around here quite awhile and have read tons. I've never seen one of the experts suggest leaves would account for an overnight loss of more than 1. Seems like they usually suggest leaves and such don't actually use up much chlorine if cleaned out normally. I do know they have indicated it possible to have algae even with CC of .5 or less.

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