The tabs should be trichlor tabs, and they do have stabilizer in them. You need a certain amount of stabilizer (CYA) in the water to keep the sunlight from consuming all of your chlorine, but as your stabilizer level rises, so does your minimum chlorine level. Take a look at the link to the Best Guess chlorine chart in Pooldoc and Watermom's sigs, and it will outline where your chlorine needs to be in relation to your stabilizer level.

Having tabs is a good thing for vacations, etc, or to raise your CYA to where you want it (we recommend 40-50 ppm for most pools), but it will be very difficult for you to use it as an exclusive chlorine source without algae outbreaks, especially toward the end of the season. Once the CYA is in the water, it is only reduced by splashout, backwashing, and very severe algae blooms, so once you get it where you want it, there should be very little adjustment throughout the swim season. Also, check and make sure your tabs don't contain copper--copper is what turns blonde hair and fingernails green, and can stain your pool liner.

Janet