Magoo and a few others over the last couple years have gotten funky batches of Promix! Exact same thing too, slow, stunty, off-colored seedling, just plain failure to thrive syndrome,... no nute, inoculants or anything else were to blame, proven by him getting a different batch (think he check lots #'s?) and things got back to normal,... OF had a similar issue with the SS#4 as you now see
... both are soilless mediums, and as such with minimal components you'd think bad batches would be near impossible, but it ain't clearly! ...coulda been the lime, or bad mixing, even some shitty peat,...
Kyote brudda, have a look in the
Reference section, there's an article there that Eyes on Fire found that sums up the types of limes, and also one on peats...
In a nutshell though, most (rock) limes are mainly CaCO3, variable amounts of MgCO3,... oyster shell is pure CaCO3, some molecular structural differences I think... Dolomite is chemically different from "regular" lime, compounded differently: formula is CaMg(
CO3)2 , a very different arrangement indeed. it has more Mg per weight, and is slower to break down because of this altered molecular construction... particle size is everything with any lime, but dolomite especially,... It's plus is that it can last longer, react slower and release less quickly than other typical limes like Ag' lime, shells, etc.... really fine stuff, like powdered will act much faster than course grit as you'd expect,... Soil chemistry, pH in particular, and 'crobes play their role as well, but pH is king here... It's safe on some levels because it can't raise the soil pH above about 7.0, but it sure as shit can make it stubborn to bring down! Worse for peat-based soilless, which works better at a lower pH vs. true soil...
Too much neutral stuff like perlite can mess with other factors in the medium's functional ion exchange capacities... I'm told it's like "watering it down", since perlite is so non-reactive in this sense, and past a point, more aeration is not necessarily better for other reasons too,... Good science went into those mediums, Promix is pretty loaded with perlite as is... I actually started using it for my carnivorous plants instead of pure peat; easier to work with and already airy enough even for them!
Any reason you don't use soil?