I’ve got soft water 0.2EC and I use Soft water nutes.
still isn’t enough Calmag for me to grow without using any.
It's handy stuff to have like. Helps buffer ph amongst other things. A lot of new growers particularly have a hard time dialing things in. Changing things a lot while they figure it out.
One of the top problems on these forums is calmag dramas in coco. I'm aware of cation exchange etc. Coco does need calmag but nowhere near what people think.
You generally find that people who use lots of it and benefit also have at least one bad habbit. Usually itd not watering it often enough or not enough volume when they do.
Too big a pot is also a common one that has the same effects.
The ph gets shafted and causes lockouts. Looks like mag def (Edit-- at fisrt).
Adding calmag fixes that by buffering the ph so a lot of folks get convinced they need high levels of it.
When in reality they should be upping the feed volume and being more accurate with ph.
Not saying that's always the case. Each nute brand is made differently and everyone's water is different but a lot of the time it is.
And you need to add quite a bit of calmag to get bad effects from it so it's hard to convince people they don't need as much.