Hi Jeannie. You also have my sincere sympathies on the loss of your husband.
I am the pool owner that JoyfulNoise referred to who has begun using the product called "Ahhsome". It is indeed the pool cleaner - not a spa product. It is only supposed to be used once a month. I bought it through Amazon. I added it about 2 weeks ago and my cloudy water cleared up nicely. Then, unfortunately, I was traveling for close to a week and typically remove the filter grids when I'm away from home. Upon coming back yesterday, I found the water was very cloudy again. Obviously, not filtering the water at all for a period of days is asking for trouble. So I started adding the usual weekly chemicals and it looks better already today BUT I also found evidence of additional white water mold. The main trouble I've been having with the mold and slime is that it clings to the plaster walls and is very resistant to removal. I've tried wire and plastic brushes and neither gets it off. The only thing that seems to work for me is to actually wrap a cleaning cloth (that is actually designed to wash cars) around my brush and do the entire pool. So, in effect, it's like taking a towel and swimming under water and wiping everything with it. It works quite well. At this point, I'm on the fence as to whether or not I plan to continue with baquacil or switch back to chlorine. As JoyfulNoise mentioned, you don't want to attempt any sort of conversion now. Continue to add your weekly oxidizer amount.
Do you also use a chemical called CDX? I'm curious as to what your husband's pool care consisted of being that you mention 25 years of baquacil with no apparent problems. So I take it that your water has always looked clear and no evidence of mold/slime prior to just recently? If so, you've done very well. I wish I could say the same. My water, over the years, has often been cloudy but I always attributed this to more of a plaster problem since our plaster was pretty well worn out over the past many years - just had the pool renovated 3 years ago. I didn't expect the mold and slime to adhere so much to the new, smooth surface, but it sure seems to be. The old plaster was all pockmarked and rough so I could understand that it could cause problems, but I didn't expect to have trouble with the new plaster.
So...the products I've been using that are designed to combat mold and slime that may help you keep going are: 1) Baquacil CDX - gets added immediately after adding the weekly maintenance dose of oxidizer and is designed to help maintain the oxidizer level 2) Ahhsome - comes in a 6 oz. container. 3) Aquafinesse pool water care tablets... Beyond that, I also use Baquacil Sanitizer and Algistat, and Baquacil Algicide.
Do you use some sort of test strips (Baquacil or Softswim) to check your oxidizer and sanitizer levels? In hot weather and warmer water temps, as well as when there is a presence of mold and slime - oxidizer is consumed more rapidly and so you may need to add more than the usual weekly amount. It can be VERY difficult to maintain a proper level. The mold and slime consume it. The less oxidizer in the water, the more likely the mold and slime biofilms will develop and thus the cloudier the water will become. There is a Taylor test kit that uses drops (reagents) that is supposed to be much more accurate. I'm considering getting one if I'm going to stay on baquacil. Also, there is the usual brushing and vacuuming that is important to keep up. Keep an eye on the filter pressure as well. Since you use a sand filter, you're likely to have fewer problems with baquacil than with a DE filter. I am not a great fan of pool store advice (used to be but am no longer for various reasons relative to things they suggested over the years that I now know were not the best advice), but what you were told seems to be correct - that the hydrogen peroxide in the Baquacil Oxidizer is just not as strong as chlorine in being able to kill these mold and slime organisms.
Hopefully some of what I've mentioned will be helpful. Can't think of much else to suggest right now. I've been on Baquacil almost as long as you and, quite honestly, it's been an on-and-off battle. I just bought new DE grids last summer and this summer they turned pink from all the pink slime that was in the filter.
Best of luck with the remainder of the season. Please keep in touch. Perhaps we can exchange additional info if we both decide to convert to chlorine next season!
Regards,
Keith