Hi Folks ....
I've been a pool owner for about 15 years, and after learning about tfp I decided to give the BBB method a try.
My current situation: CYA is high (90) despite the fact that I did a 95% drain in July 2009, and have been careful to avoid re-adding CYA through the 3" chlorine pucks or the granular shock. After doing such a large drain I added CYA to get a base level in the water again, and I thought by avoiding excessive use of the pucks I'd get 2-3 years before I reached a high CYA level again.
My water is crystal clear, but I have a widespread, persistent growth of light green algae that can be easily brushed away. I also have over the past year started to get black algae, which does seem to go away with brushing and high chlorine levels. But my reluctance to add the CYA has caused me to avoid shocking too much and avoid putting 12-15 pucks in each week, which is about what it would take to maintain the chlorine level to eliminate the black algae.
I have purchased the TF-100 test kit, and results are:
I'm looking for advice before I proceed. I suspect I should replace about 50% of the pool water, and only then start attacking the algae issues. Does this make sense?
a) in last summer's draining I shocked before draining, brushed the walls to remove algae, and then drained using pump on backwash cycle, which took about 2 hours. I've since learned that CYA can 'stick' to the walls and it's important to brush and rinse them as the pool is draining. Is that important?
b) My pool is gunite and about 10 years old. I can't seem to get the PH up above 7.2, although I'm sure I could if I kept adding sodium carbonate (left over chemical from before BBB). Pool store said 7.2 was good enough, and there are no complaints from any swimmers.
I appreciate any suggestions folks may offer. Not sure if it's pertinent, but the pool is increasingly covered with trees. From January through end of May this year there was large daily amounts of leaves, seeds, and pollen in most weeks. During this time I had switched from traditional DE to using Zeo-Fiber, and it just didn't work out. I had to disassemble the filter and hand wash the filter panels almost weekly. Seems that Zeo-Fiber will clog up filter 4-5x faster than DE will. I kept at it, thinking that I was removing longterm particles that had been circulating, but I eventually concluded that for my situation, Zeo-Fiber won't work as well as traditional DE.