I'm helping my friend/old boss rehabilitate a pool that hasn't been used in 5+ years - the landlord neglected it badly. A month or 2 ago, he and a friend began dumping in trichlor shock and quat algaecide from the Depot to attack the low chlorine and at least kill some of the algae. A few weeks ago, I've been dumping in trichlor shock on a daily basis and at least several doses(2 doses of HTH quat over 2 days, 2 bottles of polyquat over 3 days) and this weekend we used up the trichlor and started using HTH cal hypo instead. Now the water is sparkling clear, except for the black algae on the sides that is now slowly but surely fading away with daily brushing. It'll take at least a week of shocking, IMO.

I'm telling him to start on the BBB method to save on chemical costs, or to use cal hypo tablets to maintain Cl levels and bleach to tweak the levels. He doesn't have a good test kit, but I'm going to pick up one that also has reagents for CH and CYA. I'm also debating either to use bleach, cal hypo skimmer tablets, or a combo of both.

What should I do at this point? The biggest problem here is consistency and sticking to schedule - they're busy parents and they run a business as well. I'm tempted to use HTH skimmer tabs out of convenience but I think the BBB method is cheaper. The pool is a 17,000 concrete/plaster pool. At last check, free/total Cl was .5/2 before shocking and 5+/5+ afterwards. pH was at 7.2, TA was at 120.