I don't know about this but I use these sinker things that have enzymes packets I replace and it has been amazing! I got them last year and put one in a clean auto water tank and a REALLY funky one, it kept the clean tank clean and also got rid of all the algee sp in the dirty one! It does not have a taste and my cows and horses never seemed to notice. I haven't scrubbed a tank in one year even through the summer!!
They are called stock tank water cleaner they work for up to 500 gallons for one month. I don't have to change mine that often more like once every three months. You can get refills for 20 bucks for six months and the whole kit cost me 25 for the first six months. Vet approved too.
You could go to www.bioverse.com
they are wonderful! I really love them can ya tell?