I am making myself crazy trying to understand a puzzling change in test results. I apologize NOW for the length this post will surely stretch to.
On 6/10, I discovered a full-blown algae bloom (especially discouraging because I cased it with an exceptionally STUPID mistake). At that point, except for FC & CC, my numbers were solid:
pH - 7.3 (low - but I had just added acid to lower TA, and was aerating to raise)
FC - .5
CC - 1.0
TA - 90
CYA - 70 (tested five days prior, and I had added a pound to try sneaking up to 90)
So I started the shock process. SWG was turned off, and I began with 12 bottles of 6% bleach targeting a FC of around 30. Then I moved to gallon bottles of 12.5%. Everything I added seemed to be consumed almost immediately. I won't bore you with all the details, but in summary, it was a real struggle to keep FC near 30. It occasionally got as low as 22, but was always at least in the high 20's, and once as high as 44 (at 11 pm on 6/16).
I have gone through a staggering (to me) amount of 12.5% bleach in the last 10 days (~ 40 gallons 12.5% + 12 96oz bottles of 6% -- in an 11K gallon pool). Throughout this time, I was testing only FC and CC using the FAS-DPD method (understanding pH test is inaccruate at FC > 10). Water color and clarity was improving daily, but v-e-r-y s-l-o-w-l-y. Because I had been pouring SO much bleach in for over a week, I *assumed* the lack of complete clarity could be associated with some other parameter. Overnight tests had a FC drop of 2.0 & CC of .5. No... I didn't go all the way to an overnight FC drop of 1.0... but I figured I was in good shape with CC consistently at .5. Again, I had added a LOT of bleach to this pool. I wanted to let the FC drop so I could run a complete test again.
Yesterday morning, the water contained FC = 14.0, CC of .5. I did not add chlorine during the day. By 10:30 pm, I had FC of zero. I added three gallons of 12.5% bleach (which should be approx 35 ppm), and 30 minutes later, measured FC of 15, CC of .5.
This morning, I ran complete numbers, and received... Odd results:
FC - 13.0
CC - 1.0
pH - 8.0 (accurate with this FC level???)
TA - 170
(How could it be nearly double???)
CYA - ZERO
The water is still cloudy white, but I can see the bottom of the deep part (around 5.5 feet down)
So... Now what? I suspect I need to shock again, but was amazed to see CYA of zero. I suppose I must have screwed up that test, because I surely did not replace 11,000 gallons of water. But is there some environmental factor that could cause this result?
Perhaps the solution is to bring in a bulldozer and a big pile of topsoil... {sigh}
On 6/10, I discovered a full-blown algae bloom (especially discouraging because I cased it with an exceptionally STUPID mistake). At that point, except for FC & CC, my numbers were solid:
pH - 7.3 (low - but I had just added acid to lower TA, and was aerating to raise)
FC - .5
CC - 1.0
TA - 90
CYA - 70 (tested five days prior, and I had added a pound to try sneaking up to 90)
So I started the shock process. SWG was turned off, and I began with 12 bottles of 6% bleach targeting a FC of around 30. Then I moved to gallon bottles of 12.5%. Everything I added seemed to be consumed almost immediately. I won't bore you with all the details, but in summary, it was a real struggle to keep FC near 30. It occasionally got as low as 22, but was always at least in the high 20's, and once as high as 44 (at 11 pm on 6/16).
I have gone through a staggering (to me) amount of 12.5% bleach in the last 10 days (~ 40 gallons 12.5% + 12 96oz bottles of 6% -- in an 11K gallon pool). Throughout this time, I was testing only FC and CC using the FAS-DPD method (understanding pH test is inaccruate at FC > 10). Water color and clarity was improving daily, but v-e-r-y s-l-o-w-l-y. Because I had been pouring SO much bleach in for over a week, I *assumed* the lack of complete clarity could be associated with some other parameter. Overnight tests had a FC drop of 2.0 & CC of .5. No... I didn't go all the way to an overnight FC drop of 1.0... but I figured I was in good shape with CC consistently at .5. Again, I had added a LOT of bleach to this pool. I wanted to let the FC drop so I could run a complete test again.
Yesterday morning, the water contained FC = 14.0, CC of .5. I did not add chlorine during the day. By 10:30 pm, I had FC of zero. I added three gallons of 12.5% bleach (which should be approx 35 ppm), and 30 minutes later, measured FC of 15, CC of .5.
This morning, I ran complete numbers, and received... Odd results:
FC - 13.0
CC - 1.0
pH - 8.0 (accurate with this FC level???)
TA - 170
(How could it be nearly double???)CYA - ZERO
The water is still cloudy white, but I can see the bottom of the deep part (around 5.5 feet down)
So... Now what? I suspect I need to shock again, but was amazed to see CYA of zero. I suppose I must have screwed up that test, because I surely did not replace 11,000 gallons of water. But is there some environmental factor that could cause this result?
Perhaps the solution is to bring in a bulldozer and a big pile of topsoil... {sigh}
