Looking for direction on promix bx/coco/perlite mixture

Hey all, I’ve been looking through the forums for info on my plan but nothing popped out at me, figured one of you green thumbs might be able to answer…

This is my second grow, used promix with perlite at 75/25 with good results in smart pots. This year I’m thinking of changing it up a bit and adding coco to the mix. I was thinking 50 promix bx/ 30 coco/ 20/ perlite.
Using gh flora to feed in 20gal smart pots.
I’ll be doing a cal mag 5ml/gal in the barrel to expand the coco to drop that negative charge. I am going to do a top layer of hydroton, and possibly a 3” layer at the bottom of the pots. Finally, I’m also planning on building slotted stands out of 1/2” pvc pipes to raise the pots up 4” off the ground.
I guess my question is the mixture of the grow medium, does that mixture of 50/30/20 sound like good for an outdoor/smart pot grow; and thoughts on a hydroton base layer? Thanks in advance for any and all input!

You should try the promix by itself adding nothing but the nutrient you feed it I’ve had great luck this way because you know there’s nothing in the soil and you were feeding it exactly what it wants

Thanks for the reply, I forgot to mention I start clones indoors then move them outside June 21st, I live in the NE so the weather doesn’t typically get too hot or humid. So I was thinking of adding the coco and the perlite to aid in aeration, and drainage. I’ve tried straight promix on one of my ladies last year (ran out of perlite) and it seemed to sponge the water, and retain moisture for twice as long, which my not be a bad thing, not an expert lol. For some reason I have it in my head it could be better to water every three days let the roots dry up a little to promote root growth.
Just an assumption though

There is value in both depending on who is using. In a straight coco grow you could be watering daily under some circumstances. I don’t think you’d really expect to see that in a promix grow. So if you plan on being gone for a day or two every once in a while, a little more moisture retention isn’t a bad thing.