I have an Intex 15' x 42" Easy Set Pool (holding approx 3500 gl). It has been crystal clear since I first put it up 3 weeks ago, due to daily checking and management of ph and sanitizer. The total alkalinity has crept up over the last month from 100ppm to anywhere between 110 and 150 depending on the ph. It seems to average at about 120ppm. Living in Mass and the water is about 90 degrees F right now as sun has been shining for weeks.
I do not have a good test kit yet....still using a liquid one from the hardware store.
So here is the life story of my pool:
My 7 yr old daughter bought this pool for herself with her Dad for my birthday and I was totally unprepared. So naturally there was a race on my daughter's part to get it up and running. Unfortunately i received bad advice regarding the "best sanitizer" and started using bromine tabs (Bromochlor-5, S-dimethylhydantoin 98%, Providing 64.9% Avail Bromine & 29% Avail Chlorine). These would not dissolve so I then bought the granules (Sodium dichlor-s-triazinetrione 82.5% Sodium Bromide 14.7 %).
I have been oxidising it weekly with persulfate and the pool really only has my daughter and i using it for an hour or so a day. It is also covered with the dark cover which came with it when not in use. The pump runs at night and after chemicals. To date I have used about 3Lbs of Bromine granules and 3x 3" tablets have dissolved in it. There are 6 tabs floating around in a dispenser only dissolving a miniscule amount (i thought this was necessary as they dissolve so slowly-but clearly I don't really know what I a doing)
On 7/7 Ph was 7.2 Alkalinty was 120. As we had been swimming a lot and lost a lot of bromine to the sun the reading was very low to non-existant so I used the non-chlorine shock. Later in evening Bromine was around 3 so i added 5 Tbsp more of granules and later in night 2oz of Ph Rise.
On 7/8 am Bromine was only 4.4 so i continued with 4 Tbsp more and then a few hours later 4 Tbsp more.
On 7/9 am Bromine was at 7ppm however PH had jumped through roof and was unmeasurable with my kit.
So I then proceeded with 20 oz dry acid, ran pump to aerate as best i could as is outline in the pool school and saw ph drop and rise again as is described in advice in forum. So i added another 16oz of acid and the ph settled at a little above 7.2 again. Alkalinity had gone fro 140 to 130 during this.
On 7/10 I was paranoid about Algae starting as i realised that I had never really gotten the sanitizer up and sustained at the level it was currently at until this week. So I put in 3.5 oz of 60% Poly as an intial preventative dose. And ran pump for 24 hours.
On 7/11 Ph was 6.8, Alkalinity 110-120.
I have been adding Ph rise ever since and cannot get the ph to move. I added 2 oz of Borax intially to try this out and then when there was no change tried altogether about 5 oz of Ph rise.
Bromine has sustained over the last few days however we have kept the cover on and not been using it due to ph and confusion over what is going on.
As I do not have a way to check for CYA I cannot provide this info. I am suspicious that the CYA level is now high and this is causing the PH issue. It is obviously more difficult to find info on bromine pools as it is not the preferred or recommended route.
So I don't realize the bromine/CYA relationship, only that they don't bind with eachother (i think).
I will be leaving to go overseas for 3 weeks next week and the pool will not be in use. However my husband will hopefully tend to it with some chemicals when needed. Up until now I thought I would have been able to estimate how it would behave.
What is the best advice for me right now without knowing CYA level. I would happily convert to chlorine but may have to wait until next summer...unless my husband neglects it and i have to refill in a month!