GH nutes & H202...

Tree King-- me thinks the math be a bit off.
Al stated:
Canna Vega Substra for the mothers, Canna Flores Substra for flowering, Canna PK-13-14 phosphorus additive in wk 3-4. Pathogen control with hydrogen peroxide (50% strength) @ 1ml/litre every 3-4 days when topping up tanks with plain tap water... and nothing else. No wacky magic sauces, no crazy beeswax and brewers yeast additives or other silliness.

So, if you are using 35% or 29%, the math roughs out to 1.7ml per gallon for maintenance. Wouldn't 7ml per gallon be too much? I would think toxic at that level.

i generally use about 2 to 2.5 ml (29%) per gallon. In my 15g i add 1oz every few days and in my 25g i add 2oz. I've heard of people using twice as much without problems but haven't tried myself. Hope that helps!