Coco has no nutrients that come with it, so you want to start feeding now. The seed can power itself the first 7-10 days or so, but it's also safe to give a 1EC charge to it from day one.
You fertilize every single time in a soilless grow at 1.3-1.5EC with minimal 10% runoff. The runoff waste ensures the substrate maintains a healthy equilibrium... no buildup of nutes, steady pH etc etc.
Wait for top layer to begin to change color, and that's usually a good time to fertilize again. Feel the weight at this point and if you use weight as your trigger to water, it'll be the same volume of water per pot, give or take. Can also try frequent irrigation if you have good mix of perlite (30% in coco or more). I'd got some grows in before trying anything too fancy though. Keep it simple. Form a baseline. Then, when you try something new you can more easily determine if it actualyl did anything.
some manufacturers give good instructions, some do not.. hopefully biobizz gives someinfo on resulting EC or you can calculate it using an online nutrient ppm calculator on manic botanix web site.
not sure if same products but this forum posts claims to have a 1mL/L EC of some biobizz products worked out... always better to do the math yourself, but .. https://www.icmag.com/threads/biobizz-ec-values.179743/
you can simply type things in from guaranteed analysis lables into the online calculator.. 500ppm is 1ec. 650-750ppm (on hanna 500 scale) is what you want to shoot for.
@ 6pH give or take 1-2 tenths of a pH.
N/P/K
120-140
45-60
180-210
The following depends in part on the water used.. RO or non-hard water. i have very hard water and need less Ca, for example.
Ca / Mg / S
100+
85+
100+
while you don't have to always know this type of detail.. paying attention to it as you learn will hasten the learning curve.. any symptoms will be further reinforced by the data and you makemor confident adjustments. Just knowing the gist of it helps after that.. familiarity will fill in gaps.