Yeah, that's why Pooldoc recommends the Sam's dichlor--we know exactly what's in it and what it will do to your pool water. We can't say the same about the generic clarifiers, filter aids, buffers, etc--who knows what all that is, and what it'll do?

I would return it, and go with your plan of adding straight CYA along withe bleach for the chlorine. By the way, when you get the 3" tabs, make sure you check the ingredient label for copper. Many chem manufacturers are adding copper to the pucks so they can re-label them as "dual acting" and raise the prices, but you don't want copper in your water because that's what stains things green (hair, nails, pool liners, etc.). Also, keep in mind that even if they don't contain copper, they DO contain CYA, so keep a really close eye on your CYA levels if you decide to use them. In fact, if you plan to use them, you might want to only add 1/2 the dose of granular CYA and just allow the puck use to raise the CYA the rest of the way.