changed from soil to coco, due to pandemic needed to use bricks, now need to change to rockwool

[DaEarl73]

My baseline, the maths from which all my ppm calcs work, is looking at the percentage of what I'm adding, and think of it going into 10L. This is no maths.
Here we have a 3% solution. We put 1ml in 10L and we get 3ppm. No maths.
A little math tells us that in 1L of water, it would be 10x stronger, so 30ppm.
So I see that 100ppm would be about 3.3ml per liter.
It all works properly in metric.

Now while that is a healthy level, it's by no means as high as you could go. The suggestion of 100ppm is often given, and indeed livestock water supplies should be 30+ and drinking supplies can follow similar numbers. Where in some states it is in fact added, and may come out the tap as high as 100ppm or more.

It seems mine is now 12%, following it's abuse in bomb making. I'm happy to go with 2ml per liter at a push.
Quick no math.. 1 ml of 12% in 10L is 12ppm and I'm doing it in 1L. 120ppm, which I can double. I have found cuttings in wool don't like more than 60ppm added on the first day, but when rooted I have been past 500ppm, where I could actually hear them fizzing away a yeast build up I had.

The fact the h2o2 might find something to do, means it's levels are dropping. I'm in coco (and soil-less) these days, so go in around 200ppm, even on a daily routine. You may want to aim for 100ppm as that's nice fresh water, or if you want to walk in my shoes, double up. They love it, but if you only have 3% to hand, you probably need to be a little more conservative with it.

I get 5L from UK eBay for about £20, and I have tested it with strips to ensure it's right. We really don't need to be buying little bottles from markets or grow shops. Where that might cost £100

Thanks a lot. I appreciate your answers and the time you put in to write about all the details. Helps me a lot and I guess others too!