The pool calculator was originally written by "JasonLion" over at TFP and it was at TFP where chem geek (Richard) basically came up with the 5% and we tested it out and it worked very well (back when I was a Mod over there) so it's no surprise that Jason incorporated Richard's guidelines into his pool calculator. We did a lot of experimentation and 'tweaking' in the early days of TFP. The pool calculator has since been sold to pSIFlow Technology Inc. and I am not sure if it is being updated anymore.

The active ingredient in the original Optimizer is/was sodium tetraborate pentahydrate (borax). It requred the addition of acid along with it to maintain the pH. If you have the pH neutral product that does not require acid addition to maintain pH then it is mostly boric acid with some borax (about 90% boric acid and 10% borax, pentahydrate form, by weight). 50 ppm is considered optimum for borate in a halogen (chlorine or bromine) pool, 30 ppm is the lowest effective level for algaestatic effect. 50 to 80 ppm is recommended for biguanide pools but there is a very small concern of possible toxicity at the higher levels. These levels go back to the original tests done by John Girvan of Proteam in his test pools in St. Augustine and Jacksonville, Florida in the early '80s before he sold his company to Haviland and went to work for them.