This is going to be our second year with our pool, and I've decided to switch over from the chemical levels recommended in the manuals to the TFP guidelines.
I've been reading all the various threads on TFP recommended levels, and have a grasp on most of it. The only point I'm not sure on is how much CYA I should put in. It feels like I have to choose between opposing advice and I don't know which is more relevant in my situation.
First up, my pool is unusual (see specs in my profile). The weird part is that it is only 8ft by 16ft, with insulated walls and a spa cover fitted on it. I'm talking about one of the 6-inch-thick foam covers that requires lifters. The design goal was that once we get the pool up to temperature with the heater, it takes a very long time to come back down as long as the cover is kept closed. It does this very well. Between the smallness of the pool and the insulation and the cover, it cost us very little money to heat our pool last year even into October in New England.
Over in the Pool Water Chemistry post, chem geek says "Salt Water chlorine Generation (SWG) pools seem to require a higher level of CYA, about 70-80 ppm, to operate efficiently. The theory is that the CYA is slow to "store" the chlorine as it is being generated so without enough CYA there is a build-up of chlorine that degrades the performance of the salt cell."
But when the cover is down, which it is all the time we're not using it, there is absolutely no light getting in, which I would think would let me use a CYA below 70-80.
Anecdotally, we were barely pushing the SWG last year. While keeping my CYA at a 20-30ppm level, I was able to keep my FC stable where I wanted with the SWG set at maybe 6-9% with a 8-hour pump on-time. If I'm doing my math right, that's only 30-45 minutes of actual SWG generating per day...
My question boils down to this: does the 70-80ppm guideline for SWG pools still apply to my pool, or does the fact that we have such a small chlorine demand and the SWG was barely working last year win out and I should go for a lower target CYA?
We just started up the pumps this week and the CYA was still around 20ppm from last year. I'm probably going to SLAM it this weekend based on that (i.e. SLAM FC to 10), but after that I need to decide where I want to adjust my CYA.
What do any of you think?
I'm probably overthinking this and will do fine as long as I keep my FC/CYA ratio good and CYA somewhere between 40-80, but I'm being perfectionist.
I've been reading all the various threads on TFP recommended levels, and have a grasp on most of it. The only point I'm not sure on is how much CYA I should put in. It feels like I have to choose between opposing advice and I don't know which is more relevant in my situation.
First up, my pool is unusual (see specs in my profile). The weird part is that it is only 8ft by 16ft, with insulated walls and a spa cover fitted on it. I'm talking about one of the 6-inch-thick foam covers that requires lifters. The design goal was that once we get the pool up to temperature with the heater, it takes a very long time to come back down as long as the cover is kept closed. It does this very well. Between the smallness of the pool and the insulation and the cover, it cost us very little money to heat our pool last year even into October in New England.
Over in the Pool Water Chemistry post, chem geek says "Salt Water chlorine Generation (SWG) pools seem to require a higher level of CYA, about 70-80 ppm, to operate efficiently. The theory is that the CYA is slow to "store" the chlorine as it is being generated so without enough CYA there is a build-up of chlorine that degrades the performance of the salt cell."
But when the cover is down, which it is all the time we're not using it, there is absolutely no light getting in, which I would think would let me use a CYA below 70-80.
Anecdotally, we were barely pushing the SWG last year. While keeping my CYA at a 20-30ppm level, I was able to keep my FC stable where I wanted with the SWG set at maybe 6-9% with a 8-hour pump on-time. If I'm doing my math right, that's only 30-45 minutes of actual SWG generating per day...
My question boils down to this: does the 70-80ppm guideline for SWG pools still apply to my pool, or does the fact that we have such a small chlorine demand and the SWG was barely working last year win out and I should go for a lower target CYA?
We just started up the pumps this week and the CYA was still around 20ppm from last year. I'm probably going to SLAM it this weekend based on that (i.e. SLAM FC to 10), but after that I need to decide where I want to adjust my CYA.
What do any of you think?
I'm probably overthinking this and will do fine as long as I keep my FC/CYA ratio good and CYA somewhere between 40-80, but I'm being perfectionist.
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