Brown patches on bottom of pool...

[george99]

new here...but i have been using the tfp method since july of last year...this year i added an swg to my 12500 gallon above ground pool which i havent used yet...after opening, i slammed the pool...and then added salt and raised the cya to swg levels...i noticed the brown patches the bottom and did another slam which was difficult due to the high cya of 70...testing was difficult with a fc level of 33... but i did successfully pass the slam test...so i let the fc drift down to 22 and tested again...no overnight fc loss and no cc...but i did see a few new brown patches...so i am assuming the patches are dirt....also found a gritty brown sand in the robo filter...so from here on out i intend to do the overnight test and check for fc loss before i slam...i use bags of shock to raise the fc rapidly and i am suspecting that a some of the powder i am seeing at the bottom of the pool is the "other ingredients" in the pool shock or dirt from the environment

so i guess my question is...is the overnight fc loss test valid at all times or only after a slam...i would hope its valid at all times...if so i wont panic until i actually get testing numbers to validate an algae problem

hi to all and thanks for sharing...i have learned so much here...

 

[Texas Splash]

Welcome to TFP! The Overnight Chlorine Loss Test is valid and can be performed at any time. It is not SLAM exclusive.

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Your one-stop shop for all things TFP to include: ABCs of Water Chemistry, Recommended Chemicals/Levels, Test Kits, Troubleshooting, and much more!

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[george99]

thanks for responding...from here on out i will regularly check with the oclt before going crazy and spending money on an unnecessary slam...it gets expensive with the high cya and the amount of 871 drops used..thanks again i appreciate it!

 

[wireform]

But wait a minute, you said you passed OCLT but in essence you have not since it includes 3 criteria which one of them is visual. They may not be algae and in that case your good but further inspection ought to figure it out. Does it move with the brush and create a puff of a cloud or is it like moving sand which won't create a cloud and disappear. And so you know you can do the FC test using 5 ml and each drop =1 untill you get closer to the end of slam.