Hi everyone, my first time posting but have been reading on this site since my pool was built in November, 2010. We live in Long Beach, CA.
My numbers first:
pH Lowered to 7.4 at start of shocking was 7.6
Temp 80-85 was running 86-90 with cover before shocking
Now on to my problem. I have been having a hard time keeping up with the min FC level with a 13 hour run time and 100% output on my SWG. I have been keeping up by adding bleach for the last 2 months. My CYA level was low, 40, so I started to increase this to 80. I have raised the CYA to 80 over the last 3 weeks and the SWG still can not keep up. The wife has been teaching lessons so I did not want to shock the pool, and we now have a break so I have started the shock process 2 days ago. The water has always been crystal clear, CC's usually have been .2-.5 but are at 0 right now. We are losing about 5ppm FC each night at these shock levels, but only about 1.5ppm when we have a normal 5ppm FC level. My question is, should I be targeting mustard algae levels or just standard shock levels? I have noticed some yellow stains mostly on the deck and coping areas appearing this last week. There is one yellow stain in the pool next to a return. The stains are about 2" X 3" in size. The pool and deck are in full sun all day long. I tried brushing and scraping the stains with my nail, but the stains did absolutely nothing. Yesterday I sprayed a 50/50 bleach water mix on the stains and they went away. The stain in the pool has lightened up considerably. I have never added anything with metals in the water and we have good fill water. I did add borates to the pool 2 weeks ago using 20 Mule Team and MA. MA and bleach are the only other chemicals we have added to the water since we filled the pool. I will continue shocking until I reach <1ppm loss over night.
Thanks for all the help,