Re: Success with Baquacil so far
First I want to say that I am only a little familiar with biguanide chemistry but I suspect a few things...Have you been putting in the algaecide? Linerar quats are the only kind of algaecide that can be used with biguanide and they can cause all the symptoms that you describe. Linear quats are also destroyed by oxidizers, whether chlorine, MPS, H2O2, or sodium percarbonate. H2O2 does decompose to water and oxygen but you have to realize that you are dosing your pool wil H2O2 that is as concentrated as the stuff used for rocket fuel! I don't know how your pool store is testing for it but if they are using a drop based kit for H2O2 such as one from Taylor (K-1725) then the results should be accurate. If they are not then who knows what they are measuring!
11.75'x23.75' kidney 6.5K gal IG fiberglass pool/300 gal acrylic spillover spa combo; Aqualogic automation/SWCG; Pentair Clean and Clear 150 cart filter; 1.5 hp uprated 2 spd Pentair Whisperflo pump; PF:17
Retired pool store and commercial pool maintenance guy.