IMO this is the issue with soil mixes that contain nutrients.
When do you start adding nutrients and how much ?
FROM THE MANUFACTUERER: Designed and crafted as our best all-purpose substrate, BIOALL is our most flexible and forgiving nutrient-rich blend of coir, peat, and perlite, combined with our patented bioCHARGEā¢ technology.
BIOALL contains up to five weeks of nutrients, supporting lush vegetative growth through the initial stage of flowering without requiring additional inputs.
I have used the MaxiSeries in hempy/perlite and
ProMix HP in fabric bags and SIP's with excellent results.
I roughly follow their feeding schedule and measure by weight per gallon.
No issues at all and roughly the same results as Mega Crop one part !
My only advice to you, aside from using
ProMix HP
, is to wait until the plants look hungry (light green, deficiencies, etc.) before starting to feed at about 1/4 strength.
As soon as you see some leaf tip burn either back off or do not increase the amount for a while.
Hopefully someone using this combination can be more helpful.
Good luck, Cheers