I'm fighting black algae with decent success following a period when my pump went down and I had an air leak I couldn't find. System working good now and I'm maintaining FC at shock levels with 8.25% bleach from Walmart and Costco. (Very close in price). I'm following instructions I've found on TFP for dealing with black algae. Anyway, went to pool store today, where I've had good luck buying parts and which is recommended for its knowledgeable staff, to buy a stainless steel brush. To my surprise the guy didn't try to sell me Cu algaecide, but agreed that brushing and chlorine were key. But, when I told him what I was doing, he did warn me that using sodium hypochlorite would lead to clarity problems (total dissolved solids?). He noted that " big commercial pools use sodium hypochlorite (which we sell) , but they get drained every season around here. We try to keep people's water lasting 7 years". I drained my 15 year old pool for the first time last year, and have never had clarity problems once my filter got going, though this is the first year I've ever used bleach.
Does this make any sense to anyone?