Help with appropriate shock for vinyl in-ground

[Watermom]

Hi, Jim, and welcome to the Pool Forum!

Cal-hypo is ok to use, but vinyl pool do not need calcium. (The residue will eventually dissolve.) Another choice (and what most of us do) is to just use plain, household bleach for your source of chlorine. Works great, inexpensive no residue left behind, readily available. Many of us use Walmart's generic 6% bleach. It is sodium hypochlorite just like liquid pool store chlorine is but just a different concentration. (Pool stores typically sell either 10 or 12.5% sodium hypochlorite.)

The trichlor tabs in a floater are fine for awhile but they are stabilized meaning they add CYA. All pools need some CYA but when you get too much, you have problems.

Test a set of current water testing results taken with a drops-based kit. Also, tell us the volume of the pool and the type of filter you have.

You'll need a good test kit if you don't already have one. The one we recommend is the Taylor K-2006 or 2006C (same kit, larger bottle of some reagents). If you buy it through the Amazon link in my signature, the Pool Forum makes a little money on the sale which helps us keep this form online. Only buy if the seller is Amato Industries, however. Some other sellers are substituting the K-2005 which you do NOT want.

Hope this helps!