Burn Out 35?
That's lithium hypochlorite, a product much loved by BioGuard as a . . . WALLET SHOCK! No, it doesn't have much CYA in it (none!).
You are going to a BioLab store?? Please do all the following:
1. Stop draining the pool.
2. Read this long post about Biolab: http://www.poolforum.com/pf2/showthread.php?15052
3. Get a cheap OTO/phenol red kit, today if possible, and tell us what your chlorine and pH levels are. If you can get a HTH-6way, you can find out what your stabilizer level REALLY is. (No, you can't trust the BioGuard test results, and especially not the "Alex" computer!)
4. Order a K-2006. See this page; it will also explain about OTO kits and the HTH 6-way
5. Add 3 gallons of plain 6% household bleach daily, till you reach a DARK yellow (past 5) level on your OTO kit. Use bleach to maintain, till you get the K-2006, and we can find out what's ACTUALLY in your pool.
Be very, very careful about draining a fiberglass pool. If there is ANY water in the ground around the pool, it can push the pool OUT of the ground. At that point, your other issues will be moot.