We're entering our sixth year of pool ownership, and I really think I'm learning something new each year. However, I still have quite a hard time with algae and was wondering what I was doing wrong. Right now our pool is clear blue, but there is some slight algae growth on the cove (the part that connects the walls to the floor). I'll try to give as many stats as I can:
Free Chlorine: 5 ppm or more? (Test kit only goes this high)
Total Chlorine: 5 ppm or more? (Test kit only goes this high)
pH: 6.8 (Yes, I know that is too low)
Total Alkalinity 50 (Yes, this is also too low)
Cyanuric acid (CYA or stabilizer): 30
Pool size is 20K. We have a vinyl liner, and it's about 4.5 feet deep all the way across. We are currently using chlorine 3" pucks (using a in-line chlorinator) and dry shock (sodium dichlor). We have a 3/4 horse pump and cartridge filter (75 sq. ft.) I have been told our filter is too small for our pool (the builder who did the pools in our neighborhood back in the 80s used smaller filters to cut costs).
To give you an idea of outdoor conditions, I am in the Midwest, where we have been getting 80-ish degree weather and high humidity. We also have had some showers come through the area in recent weeks. In addition, the pool is situated on the south side of the house with NO shade, and a white vinyl fence surrounding the pool. Pool temp has been 80 degrees this week.
It seems every year I always have some kind of algae growth. I usually never have a large bloom where the whole pool is green, but it always seems there is some kind of new growth on the cove or bottom of the pool. Is this normal for my conditions? I always try to keep the chlorine levels quite high, but I'm not always the best on vaccuming or brushing. I try to get to that at least once a week.
I'm also having a small problem trying to keep the PH and Alk levels up, too. I have been adding baking soda (I think this is used to raise both PH and Alk?) but it seems as soon as it goes up, it's back down again.
I hope I have given enough information here! Thanks for any suggestions.