Came home from vacation July 30 to a nice outbreak of yellow/mustard algae - seems like the only kind I ever get.
Did all the recommended mustard aglae attacks as far as Slamming, brushing, etc. No signs of algae for about week, water totally clear for 5 days, but I just can't seem to pass the INITIAL Over Night Chlorine Test, I'm losing anywhere from 1.5 to 2.0 PPM each night, testing at 9pm and again at 9AM (shade tree on each side of pool so sun is off of it before 8pm and not back on it until 930 or 10 AM). I'm talking here about the initial algae treating SLAM, not the "pump it up a little higher at the end for Mustard Algae" Slam.
It HAS been cooler and dryer air then we normally get in August, could it be evaporation at night?
Does it matter if I have the cover on or off? I know Shock/Slam levels of chlorine aren't good for a cover (mine is totally wrecked from past years of having it on while Shocking/Slamming, bubbles all falling apart). Should I put the cover ON to reduce evaporation and see if it holds?
It's been cool so we haven't really been in it much if any at all.
FC = at least 14-15 all the time, occaisionally a little higher
CC = 0 to .5
CYA = 30 to 35
Thanks for any advice.