walmart sells soil analysis kits if you really want to get into that. also measures npk aswell as ph. vdn tire sells these aswell depending on your location (country) or u can buy a soil ph pen. alot more expensive thpugh and wont check npk. the analysis kits are 10 to 15 bucks max
tap water id do every 2nd or 3rd if RO every watering.
6.3 to 6.7 ish. why watering with 6.1? if its an organic grow then u dont even really need to ph water unless its waaay out
"a blend" it can still be tested. and usually soil ph will drop over time as things break down.
Little white dots on the leaves can also mean bugs so if you got a loop or a good enough zoom on your phone flip some leaves over and check for little tiny bugs might not to be able to see them with the eye
