Just installed the Aquarite in my 34,000 gal inground vinyl liner pool... Before have never had to worry about Calcium but now what i've read about saturation index i'm thinking i need it. Do I? Right now my Cal is 30, according to the calculator I'm going to have to add 57 lbs. to get to 200... do I want it that high? And my last question (for now) is where's a good place to buy it? Thanks!

I think you'll get a lot of varying opinions on whether you need to even be concerned about it. I don't know, I've never owned a vinyl pool. Even the published ranges for CH in vinyl seems to vary. I've seen between 80 - 150 and another source says 200 - 300 to have good water balance.

You really need to take into consideration other factors, whether you believe it to be necessary or not. For instance, what does your vinyl pool manufacturer say it needs to be. If you have a pool heater, what do they recommend. Same with the chlorinator. Sometimes there is verbage about void warranties if you have not kept your water in their recommended balance.

The saturation index tells you when your pool is fully saturated with calcium carbonate (when the index is 0.0). Calcium carbonate saturation is required to prevent corrosion (dissolving) of plaster/gunite/grout surfaces exposed to water. It is not necessary in a vinyl pool unless you've got some sort of tile line (so would have exposed grout). There is dispute as to whether it is needed for a heater, but most indications are that it is not and that pH is the far more important factor in the corrosion of metal heat exchangers.