Quote Originally Posted by ivyleager View Post
Sat Index (-.30 - 0.10) -0.96 CORROSIVE (what the...??)
Total Dissolved Solids (1-1500) 100 OKAY
FC 4.5 HIGH
TC 4.4 HIGH
CC -0.1 OKAY (how can you get a negative CC?)
pH 7.6 OKAY
CYA 16 LOW ("add 4lbs of conditioner, don't backwash for 48hrs")
Copper None
Iron None
TA 21 LOW ("add 20lbs of baking soda: half today, half tomorrow")
CA 94 LOW ("add 25lbs of calcium, 5lbs at a time")

So my questions are: what the heck is a saturation index and how can it be corrosive, and how can there ever be a negative CC??

While I was there a poor soul came in and picked up 25lbs of calcium for their vinyl pool (a huge bucket!!), pH increaser, another bucket of 3" tabs, and a skimmer bucket....$85!!!! Pool stored.

CaryB
Anyone but Buffalo (Go Sens! SWEEP!)
18x36 IG vinyl; 24K gals; sand filter
Somewhere around here there is a formula for figuring the Langelier saturation index, which is supposed to tell you how corrosive your water is to things like heater elements, etc. It was originally designed for closed boiler systems. Most of us around here don't really put a lot of stock in it, but the subject has been debated to death in the past in the China Shop.

You're right in that you can't have a negative CC. And while we're at it, FC + CC = TC, always and forever...the fact that the pool store hasn't figured that out yet would lead me to completely believe my own testing over theirs. And as far as calcium goes, the only reason I can think of for you to buy calcium might be to use as sidewalk de-icer!

Go with your own numbers, and put your money toward pool toys!! Aren't you glad you're not the poor sucker that came in behind you????

Janet