Day 5= the battle against visible Algae Monster is now pretty much won! Water is clear blue, visibility is good, seeing easily the details in 4 foot depth and seeing relatively clearly even in the deepest spots. A little bit of blurriness in deeper waters still remains, but this pool can no longer be considered "cloudy". I could vacuum efficiently for the first time (vacuum to waste of course).

So in all, it took approximately 1 week and half from pool opening to get things under control, but I wasn't agressive with the filtering and BBB from the get go. I did invest a few days mostly stabilizing the pH and alkalinity, with no bleach attack AKA shock treatment. This was following pool store advice, but now I know better; whilst I don't regret working on the pH and overall chemistry, shock treatment really is the key. From the moment when I started chlorinating agressively with Liquid Bleach, it took only 5 days to really clear this thing. At its peak, my shock treatment was 4 gallons of bleach in a night; overall, I might have poured in approx. 7 gallons of bleach + a few pounds of calcium hypochlorite (in the early stages only, before I knew more about BBB methodology), along with my tablets in the floater.

Moderators, I believe we can now close this thread. I know that I will certainly need a lot more work to get this pool crystal clear, and will certainly benefit again from your experience! But at least now, the invasive green algae issue (topic of this thread) has been dealt with and I can move on to other phases.

Over the course of the summer, I intend to:
-keep chlorinating with tabs once in a while, whenever I leave for a few days and to get some stabilizer in the pool (not to often)
-otherwise, keep chlorinating with bleach for maintenance and keeping in the 5ppm range
- use algaecide very sparsely, just to help with prevention when the water gets a little blurry and that I feel unsure about algae resistance
- monitor my water chemistry and adjust accordingly (Cl, pH, Alk, CYA); I intend to to at least one trip in the USA so that might be the opportunity to invest in that Taylok K2006 testing kit!


Thanks again AnnaK and PoolDoc for the support!