Well it is very close to nutrient free.
I don’t think the formula changed. As long as I’ve been using it I’ve understood it to have that ‘starter charge’ in it. But yes- it’s just a small amount so for the most part the stuff can be regarded as nutrient free.
It’s only relevant to very young seedlings. Also because of those starter nutes I find it’s not very good for rooting clones in, whereas truly nutrient free mediums like coco, rock wool, and perlite work very well.
I've been using Sunshine for 15 years or so, always treated it as being nutrient free, and used the GH schedule from the get-go. My last seedlings did get some burn, and that was a first. I wonder if the formula has changed recently. I still find it a great hydroponic media. It is very forgiving toward pH, and doesn't require near as much care as conventional hydro methods. It holds a lot of water, drains good, provides aeration of the roots.
I don’t think the formula changed. As long as I’ve been using it I’ve understood it to have that ‘starter charge’ in it. But yes- it’s just a small amount so for the most part the stuff can be regarded as nutrient free.
It’s only relevant to very young seedlings. Also because of those starter nutes I find it’s not very good for rooting clones in, whereas truly nutrient free mediums like coco, rock wool, and perlite work very well.