cocoforcannabis.com -- hands down best guides and articles. avoid the forums, as you should on any other site... always be skeptical of anecdotes.. always look to verify what 'grow bros' say.
Soiless is the same regardless of coco or something else.
Alwys fertilize.
Always get 10% runoff or greater.
Wait for appropriate dryback and repeat.
Don't overthink it. Yes, the 10% runoff is essential to taking advantage of soiless/hydro growing. By doign so, over time any symptoms you see are 100% about adjusting the formula and all other factors are eliminated. Take notes of how you fertilize from start to finish. Adjust based on what you see. Avoid problems in future. It is very feasible to find consistency and never be concerned about running as many strains as you want coinciding.
How much dryback? There's some user preference here. I would suggest a more pronounced wet-dry cycle early on in vege phase. this will promote a greater root mass that you can take advantage of later with more frequent fertigations allowing less dryback/loss of weight between. As i enter flower, i don't wait as long to re-fertigate. So, early on i let the top surface changen color -- if plant shows any sign of wilting, that's too long. Later on, the color may not even change on top when i fertigate. I don't use coco anymore. Not a big fan of it, tbh. Nothing done with coco is exclusive to coco. Never let that hold you back due to some deification of this hippy medium, lol. it's also not 'better for the environment" as it wastes a whole shit-ton of fresh water to make it non-lethal to plants as well as contribute to aquifer pollution due to runoff of the buffering solution... similar to farm irrigation runoff concerns.
Multi-fertigations per day require the right-sized pot. You need to get about 1/3rd weight loss between irrigations to warrant multi-fertigations per day, and from what i read no point in doing more than 3. So, the plant has to drink fast enough relative to pot size to warrant it or else you'll just cause root rot. I've never bothered to do this, more power to you if you do. I doubt the return is worth the effort.. might shave a day or two off a 5+ week vege?
Definitely use 33% perlite. The "#2" size is best unless it's pulverized to dust. Brand can matter a bit there. Avoid the super chunk. The pre-packaged 70/30 is good enough, too. 1/3rd is a guideline and a few percent of volume less won't matter.
Coco isn't magic. It's simply a soilless medium. Don't project superhero qualities onto it. Treat it just as you would any other soilless medium. Beware of bad batches.. end up with dead or saline-sick plants. I'd recommend promix HP/BX or whatever it's being replaced by called something fancy like active-g or soemthing, lol. Those bales do need more perlite or similar - i'd suggest vermiculite over perlite any day due to it adding some plant-available silica. Sphagnum peat moss needs 50% of volume to be perlite/vermiculite or similar amendment for best gas:water mixture that will match "70/30" coco. Typically cheaper route with promix, too.
If stored well, soilless should last a long time. if it totally dries out may need a wetting agent (sufactant). When any solid medium dries out it can become hydrophobic. It's not ruined, just needs a wetting agent applied. Feel free to store excess in a dry spot.