Got home from being away for several days, and was met with what I had feared! Appears to be Mustard Algae. (Photos don't really show the mustard yellow color, but it's there... Shady side of pool almost looks like a yellow film, with heavier, darker deposits on the floor in areas of low circulation)
First, a little history; not totally sure I ever got it completely eliminated after an outbreak last year; followed SLAM, but have had "possible recurrences" a few times when I didn't vacuum or brush for a few days, but not this bad. Had done SLAM to 20ppm ABOVE chart levels for my CYA at the time, continued at mustard slam level for 3 days after all conditions were satisfied, and then always kept the level at the high end of recommended range since. However, I did have to leave the pool with no direct care for 10 days this time, and looks like it didn't survive. I was floating pucks while I was gone, and they appear to have kept the Chlorine up, but apparently not enough.
So, Step One: Test Results from today:
pH=7.9 (staying high even with addition of Muriatic Acid lately...)
FC=2.2 (I normally keep it between 4-5ppm with liquid when I am home)
CC=0.0
TA=50
CH=190
CYA=20
About to go backwash the filter, brush, brush, and brush some more, and add Liquid Chlorine to bring level to target 15ppm and bypass pump timer to keep it on throughout the SLAM process. Also adding water, as I appear to have a slow leak plus a lot of evaporation while I was gone... probably adding ~2200 gallons to get back to full.
Anything I am forgetting, or getting out of order?
Thank you!
First, a little history; not totally sure I ever got it completely eliminated after an outbreak last year; followed SLAM, but have had "possible recurrences" a few times when I didn't vacuum or brush for a few days, but not this bad. Had done SLAM to 20ppm ABOVE chart levels for my CYA at the time, continued at mustard slam level for 3 days after all conditions were satisfied, and then always kept the level at the high end of recommended range since. However, I did have to leave the pool with no direct care for 10 days this time, and looks like it didn't survive. I was floating pucks while I was gone, and they appear to have kept the Chlorine up, but apparently not enough.
So, Step One: Test Results from today:
pH=7.9 (staying high even with addition of Muriatic Acid lately...)
FC=2.2 (I normally keep it between 4-5ppm with liquid when I am home)
CC=0.0
TA=50
CH=190
CYA=20
About to go backwash the filter, brush, brush, and brush some more, and add Liquid Chlorine to bring level to target 15ppm and bypass pump timer to keep it on throughout the SLAM process. Also adding water, as I appear to have a slow leak plus a lot of evaporation while I was gone... probably adding ~2200 gallons to get back to full.
Anything I am forgetting, or getting out of order?
Thank you!
