My first post, but I've been reading and reading and found so much helpful info on this forum. Thank you. I have a degree in chemistry, so I do understand the technical parts of pool chemistry, but since I've never put TFP/BBB into practice, this is new to me.
I have to start by saying my pool is very clear, but I think it's by luck. All summer my FC and TC has been testing at zero. Because my former pool supply place had me convinced I needed to add more granular shock and Cl tablets (I know better now!) I was a shock junky and dumped pound after pound of dichlor in my pool weekly. After finding TFP and reading, I realize it's because my CYA is way too high. I bought a Taylor 2006 test kit and the CYA was about 100 (I'm still kind of fuzzy on exactly how opaque the test sample has to be to not see the dot...I think I'm imagining I'm seeing it when I probably don't). So last week we bought a pump and pumped out the upper hot water (about 88 degrees) for two days, while refilling it at the bottom with cold water from the well. I expected the temperature gradient to keep the CYA water separate from the clean water.
After pumping I tested the CYA and it is about 80. I know that's high, but our well needed a break and I really needed to get chlorine in the pool (this may be where my mistake lies, which is why I'm asking you.)
So I went ahead and started the SLAM yesterday afternoon.
Using the CYA/Cl chart and the pool calculator, I put in a little over 6 gal of 10% liquid chlorine.
After a few hours I tested again and my FC was down to 8. SLAM says to bring it back up to shock level, so using the calculator again, I added another 5 gal of chlorine.
Tested again this morning and the FC is down to 3. I'm supposed to add another 6 gal of chlorine.
So my questions are
1) Do I just keep using the pool calculator and keep adding more chlorine? According to the calculator, I need to add another 6 gal. I know the CYA is high, so is this normal numbers for a clear pool? There are no signs of algae.
2) Does the Cl bonded to CYA show up in the TC test, or is the TC just the FC plus the chloramines? I don't understand why I initially had zero TC when I initially was shocking and using Cl tablets.
3) Do I truly need to forget about SLAMing and just get my CYA down?
4) Short of running the pump again for a few days, do you have any other suggestions?
Thank you all so much! And if there is more info on my pool that you need, that I haven't put in my signature line, please let me know! (I'm a newbie, obviously!)