New member

[7sanders]

After a month of beautiful water and LOTS of swimming... we have something going wrong

We were only loosing chlorine during the day... starting most days between 3-5ppm, but by the end of the day we were between 1-2ppm (figured high bather load and sunlight loss - pool gets used 2-6 hours most days). I would add enough bleach to get back to 4 or 5 ppm and it would be between 3-4ppm each morning. Last week the pool started to get a little cloudy and we appeared to have a lot of dirt/dust in the pool. Hooked up the vacuum to the filter intake and cleaned the bottom of the pool (turned the filter cartridge brown). Replaced the cartridge and cleaned the dirty one. A couple of days ago the pool developed a greenish hue, clear water on top, and slightly cloudier at the bottom. I have been adding bleach 2-3 times a day to keep the OTO test kit (HTH 5 way) in the orange range. (Sorry, no Taylor kit just yet). It has not dropped below 5ppm in the last 3 days. 20 minutes after adding the bleach, I brush the walls/floor/skimmer/return etc. (ladder has been removed). It always stirs up what looks like brown dust on the bottom. Some gets caught in the filter cartridge, some must be blowing right on through and back into the pool. (Intex Type A cartridges - Unicel's are due to arrive from Amazon tomorrow).

We have had highs of 110+ for quite awhile, so the water temp has been in the high 80's / low 90's.

Chlorine orange on OTO test kit
PH was 7.8 before bringing the pool to shock levels (I understand that the PH test is not reliable when chlorine levels are very high? but it shows as 7.8 now too)
CYA was 30-40ppm before letting the final 3/4 cup dissolve.
TA is about 150

I'm wondering if I'm fighting mustard algae, or if it's just pollen/dirt/dust etc. I'm hoping that the Unicel cartridges will make a big difference. The water definitely has less of a "green/tan hue" today than it did yesterday (although, on grey overcast rainy days it seems enhances the "green" look - even the sky looks green around here before thunderstorms, especially those with hail).

I have some pictures here:

water color



residual "dust" left on ladder steps after removing from pool and allowing to air dry



pockets of "dust" on bottom



Thanks for any advice you can give!