Watermom's got you on the right track, but I just wanted to add a comment--take a look at the ingredient label on the trichlor "plus" tabs. If you see copper listed as an ingredient, then I would advise you not to use any more of those tabs, even when you get the chemistry straightened out. Copper is an algaecide, but a large enough amount of it can and will stain your pool, blonde hair, fingernails, and anything else it can. Also, once the copper is in there, it adds a whole other dimension to pool care that is a lot more trouble and time consuming. My advice is to avoid it by not adding it in the first place.

Janet