Brand New to this - Yellow Substance

Apr 25, 2017
Orlando, FL
Hi, I just took over my own pool care and I have a couple of questions.

I am using a Taylor K-2006 to test my water. I have a 10K gallon pool, fiberglass, SWG. I was running the pump 9 hours per day at 30% on the SWG until Saturday when I changed it to 6 hours per day and 25% on the SWG.

My very first test on Saturday had these results:
FC - 9
CC - 0.6
pH - 7.8
TA - 260
CH - 190
CYA - 80
Salt - 3300

After the test is when I made the adjustments to the pump and SWG run time and percentages to bring my FC down. I also followed the Pool Math and brought my pH down to 7.0 in order to decrease my TA. I added chemicals to increase my CH. I've tested daily since then and have noticed a yellow substance forming in my pool. This substance was slightly there on Saturday, but has increased since Saturday.

Today, my results are:
FC - 8.8
CC - 0.2
pH - 7.0 (I'm running two water features to attempt to increase)
TA - 80
CH - 320
CYA - 70
Salt - 3300

Now, back to the yellow stuff. When I brush or vacuum, I can see a "cloud" of particles moving in the water. When I look in my skimmer basket or clean out my cartridge filter, I definitely see the yellow substance. It is bubbly when it is on the surface of the water. I scooped some out and put in a plastic cup and the bubbles haven't diminished. It slightly stains the inside of the cup and my hands a faint yellow color when I touch it. I've attached a picture of my skimmer basket with the yellow substance inside.

Do I need to do additional treatments due to the yellow substance? Should I increase my pump time back up to 9 hours and just lower my SWG more? Anything else I am missing? Hoping to learn all this pool stuff so that I don't have to use a service or pool store! :)



Well-known member
Apr 20, 2017
Not sure what yellow substance is as others are way more qualified than me, but was curious how you dropped your TA so fast? 260 to 80 in 3 days seems impossible without lowering ph below recommended levels. I've been trying to lower mine from 180 to 100 and have only dropped mine by 30 using muriatic acid and keeping ph above 7.0
Apr 25, 2017
Orlando, FL
I don't really know how I dropped it so fast. It went from 260 on Saturday to 125 on Sunday to 80 both yesterday and today. I added the Clorox version of pH down on both Saturday and Sunday to keep my pH at 7.0 both days, because it is what I had on hand.


TFP Expert
LifeTime Supporter
Jan 6, 2010
San Dimas, CA (LA County)
If that test kit is brand new, you might have static electricity on the TA reagent, which makes the drops smaller, which makes the test result artificially high. That may be what happened initially, and now it's somewhat dissipated. Just wipe the tip with a damp paper towel before testing for the next week or so to be sure.

Could the yellow stuff be pollen?
Apr 25, 2017
Orlando, FL
Thanks for the tip on the TA reagent. The kit is brand new so that might have been what happened. I'll start wiping the tip. I'm hoping the yellow stuff is pollen! If so, I assume it will just cycle itself out as the pump runs?