Hi everyone, I have just been wondering about Cy Acid and if I really need it. This is my situation. I have a $900 Bestway 6.7m Vinyl pool which has been up for about 2 months now (my first pool). The water has been testing perfectly everyday (to me) and is crystal clear and beautiful to swim in. I have a SWG that is way too big for my pool allowing me to run it at around 20-50% depending, at 3 hrs pump time per day. It is unseasonably cold here atm, around 11 C (52F) at night and 20C (68F) day temp, so the cover has been on all of the time for the last two weeks. My well water here is very good which is what I have filled my pool with, it is very soft and has a starting pH of 4.
So 7700 gallon pool, starting pH4
9kg of DOT Solubor added (probably too much)
120kg of pool salt for SWG
A little acid and sodium hydroxide to get pH right
SWG is a Zodiac Clearwater 170 gram Cl per 6 hours max output.
1600 gph sand filter run for 1 hr in the morning and 2 hours in the evening.
Pool now tests the same everyday using HACH Aquacheck 7 test strips.
T Hard zero
T Cl 1-5 usually 3 or less depending on day
Free Cl 1-3 usually around 1 or a bit more
pH 7.6 tested with Hanna pH/EC Combo model HI 98129 (constantly calibrated).
TA around 80-120
With the cover on atm the Free Cl was climbing so I cut the SWG back to about 20%, still 3 hrs pump time. This is our hottest months of the year usually anywhere from 30C up and sometimes 40C so as soon as it warms up again the cover will come off and I will run the SWG at about 50% to raise the amount of Cl produced to counter for the extra swimming and the sunlight. Anyone have any issues with the above so far?
Now this is my query. As I have a large SWG that can easily and cheaply produce as much Chlorine as I want, do I really need to use Cy Acid? I've read on here that I do, but I have also read that I will need to up the free Cl to 5 or so to counter the Cya. Wouldn't I just be better leaving the Cya out of the whole thing and just keep doing what I'm doing, running the free Cl at around 1 to 2? Does it really matter if the sun is going to burn some off? I can understand that if you're buying liquid chlorine everyday that you would want Cya to help protect it, but I don't think that I need it with a small pool and a large SWG?
Also I will probably cut the pump back to 2 hours per day and up the SWG % to compensate.
Sorry for the long winded question and thanks in advance for you help! Happy swimming!