I am another 100% NZ sphagnum grower for my Paph, Phrag, Phal, Milt, and Catt plants. I am an indoor grower under LED lights. I think it was Ray some other place and time who made the point that it isn't wetness that is the downfall in sphagnum, since we know that orchids do well in S/H and even in pure water culture. It must be chemical imbalances that lead to trouble over time as the sphagnum is actively messing with electrolytes.
I feed at 40 ppm N with K-Lite with KelpMax at only 1:800. Like Rick, I need to add tap water to my fertilizer mix to obtain enough total alkalinity. I monitor the effluent of pots periodically for EC and pH. I also repot my plants at least once a year and often twice. All of these things are difficult to do with a large collection, but I can do it with about 100 plants. I also water each plant only when the top has gotten to the right degree of dryness for the type. I rarely see root rot.
There may be no perfect medium for growing, only one that works with all of the other conditions of the growing area.
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