The part that a missing is the "why".. It's also different info than you posted before.. You said that they told you to use 40g for 15 liters... That doesn't match the info in your last post.. According to that email they say to use 30g total in coco or 15g total in soil... Either way, it sounds like you've been given conflicting info from bio tabs.. Did you tell them you are growing autoflowers and not tomatoes?@low_and_slow @Proph I got another email from biotabs today out of the blue. Just throwing it out there, here's what it says,
Hi. If you use coconut, you should add 2 grams of powdered dolomite for each liter of substrate, mixed at the same time with Startrex and Siliciumflash (optional).
In the case that you use soil with one gram per liter of substrate you will have enough.
Regards and good luck.