
.... Hmmm, this I've seen before, but never figured out exactly what it is,... the patches go necrotic, but stay greenish, dry out quickly too,... it's not a defc. I don't think, wrong symptoms...P would be the closest, but that's seemingly unlikely in a "complete" water only type soil (assuming it is?),... and assuming it's cooked enough,... richness can be an issue early on, often folks make a small core pocket of milder soil mix (like seedling mix plus the reg. soil) to start in,... Some of the other symptoms do look "hot soil" related,... new growth looks solid, and that's good news!
So water pH,.....high, bad in fact at 9.0! With very hard water, over time cumulative CaCO3 from it can start driving pH up, but you're no where near that either way this early,... other TLO/"super" soil co's suggest pH'ing water to 6.5-ish, using citric acid (gentle stuff vs. reg. pH down),.... And lastly, soil pH is always in play! ...get an soil pH probe to take measurements directly in-pot, only was in fact with these soils, never flush or try to get run-off to test,.. that's inaccurate anyway,... the Accurate 8 is a good one, or the more spendy bulb electrode types ( same as a pH meter, but made for soil testing; do NOT use a pH meter for liquids only to test actual soil, just a heads up).... So, other things may be in play with that water, depending on what it was tested for,... I recommend getting different water, that hardness is going to be a problem...