Just a vent and review of why you should know at least a LITTLE about pool water chemistry in general and about YOUR pool in particular before heading down to your local pool store.
I had to go down to my local pool store today for some testing chemicals. And for kicks and giggles I always take a sample of my pool water to see what they come up with and what they "suggest". I'm so stinkin' glad I know what I know! Those poor customers today were getting taken for one heck of a ride.
EVERY person who had their water tested while I was in there was told their phospates were high...EVERYONE. They told me mine was 500 ppb and tried to sell me a couple of jugs of the phosphate remover they so conveniently had on a HUGE display right next to the water testing area. I told them I'd deal with that problem IF it ever became a problem. The guy asked me if I knew what phosphates could do. I politely replied that I did know what phosphates could do and again told him I'd deal with it if that ever became an issue. I haven't put anything in my pool except BBB, muriatic acid and salt in years, so how did I "suddenly" get a high level of phosphates in my pool when THEY just tested my water last month...BEFORE the lovely display was added?
They also told me my CYA was "a little low" at 30 ppm and tried to sell me a large bucket of CYA. First off, I have a salt system and my CYA should be 60-80 (manufacturer recommendation), not the 30-50 they recommend at the pool store. And second, I tested my CYA last week and got 60~70 (right about halfway, so about 65), which is right in line with what I expected after adding the last round of CYA a couple of weeks ago because I was only at 50. (Just installed the salt system this spring, so I've been adding the CYA a little at a time over the past 2 months before I turned the salt system on 3 weeks ago).
They also tried to sell me calcium. I have a vinyl pool. He kept trying to argue with me that I NEEDED calcium or my liner would deteriorate. I told him the sun would deteriorate my liner before low calcium would.
Their FAC test came back pretty much in line with what I got (3) but their pH test came back a little higher than mine. They didn't even test for TC.
Oh, he also questioned why I use both the FAS/DPD drop test and color matching chlorine tests. (I was picking up reagents for both.) I told him I used the drop tests when I wanted to get an "exact" reading or when I was shocking the water. He had the gall to tell me that color matching was MORE ACCURATE...hu?
That's pretty much all I hear from the pool store people. I only have them test my water for entertainment purposes. I need to just start ordering all my test stuff from here and quit going downtown. 8)