Why does pH drop only in the winter

[chem geek]

I am still perplexed. Even bacterial conversion of CYA to ammonia would tend to make the pH rise, not fall. The only thing that has the pH fall is when chlorine gets used up or consumed -- oxidation of ammonia or other organics is an acidic process. However, if you add a hypochlorite source of chlorine, then that exactly counteracts that and in fact has a small net pH rise due to the excess lye in bleach and chlorinating liquid. If Trichlor or Dichlor were being used, then a pH drop would be expected.

How about your TA level? Has that dropped some as well? An acid would drop both pH and TA.

[jereece]

Actually since my pool is AG I learned not to worry about alkalinity. Testing showed that as alkalinity increases the greater my pH would fluxuate. With alkalinity low, pH is stable as a rock. See this string of posts - http://www.poolforum.com/pf2/showthread.php?t=7870. I have not checked it in years but am confident my alkalinity is very low.

I added 2 boxes of Borax and pH has come up to normal.

This has me perplexed as well.

Jim