I've been maintaining my pool, which is just a 15' round Intex metal frame ABG with a sand filter, for several years exclusively going by knowledge that is promoted on this site and I've had varying degrees of success -- that is, I use liquid (12.5%) bleach to maintain FC @ around 4ppm with 40ppm CYA, I've tried Borates that have helped out here and there, etc. Only at the very beginning of the season is my pool crystal clear and sparkling, but near as I can tell I'm not doing anything wrong. However, yesterday, I went over to a relative's house and swam in the cleanest pool I've ever swam in, so I asked my Uncle what exactly he does w/chemicals and filtration...
He has a larger pool (around 10K gal.), oval ABG with a large sand filter. He uses ZERO CYA(!) and maintains an FC of 1 ppm (!), and no borates. He claims he adds 1/3 of a gallon of chlorine a day, which, when looking on the Pool Calculator, should be bringing him up to about 4 ppm or more -- so that was somewhat of a head-scratcher. He does use a nylon bag over the screen on his skimmer that he cleans every day (I do not), but he only backwashes his sand filter about twice per season which seems odd. When I SLAM for algae, I'll backwash several times and use DE (which he also never uses) to help speed things along.
He also uses a 90-day proactive algae treatment once per season, and has absolutely zero problems with algae... in my case, I occasionally get blooms that I have to deal with through SLAM'ing, but I'd prefer to not get them at all and I really want clearer water. The product he uses for algae is FROG Leap All-Out, and I can't even find any information on what type of chemical is in this product. He also said he uses Leslie Ultra Bright Water Clarifier about twice per season, which I know is frowned-upon on this site or deemed completely unnecessary (same with algaecide here, generally).
Rarely he has to shock (only after very heavy use weekends), but when he does, he said he uses Cal Hypo and went as far to say that the calcium helps a vinyl liner, which also goes against conventional TFP wisdom... So I guess my question is, why does a guy who goes against so much TFP wisdom have the cleanest pool I've ever swam in, and why shouldn't I try his methods next season with my own pool?