Yes, Ray. That's why they tell you not to wash it when potting.it washes away over time. My information came from Glen Decker at Piping Rock.

I see this tread came alive again with people talking about how long this stuff lasts / things don't need to be re-potted as much. Does anyone have any specific thoughts around how Paph's are with it? I use it myself, but two of the large nursery's I get a lot of stuff from here still tell me to re-pot my Paph's at least once a year. Even when Orchiata is used.

Anyone have experiences they would care to share?

I listened to a talk by Glen Decker of Piping Rock Orchids just the other night. He doesn't use Orchiata but instead some US sourced bark, I forget exactly what he said. He says that he likes to repot paphs at least once a year and would repot even twice a year if he had the time. He had a Phragmipedium kovachii for sale for only $375 and he was setup for accepting credit cards but I resisted the temptation and bought several paph species instead.

Yes I have heard the same (and do the same) but I was curious what the experience was with, specific to Orchiata, since the discussion here was that it lasts so much longer than other mediums.

This might not be the main reason for the pH change of media over time. I recently read a study about the reason of pH change. This study was just over 6 months, and they were mainly interested in sphag moss. But in addition to sphag moss, they used orchiata in one experiment. Their experiment showed that the main cause of lowered pH is coming from roots excreting protons and other stuff. Orchiata went from pH of 4.8 to 4.2 after 27 months while sphag went from pH of 3.9 to 2.9. But in sphag, if plants are not growing pH doesn't go down. So washing effect of lime is probably a minor contribution.

Only the abstract is available, but if you want to read the full article, email or PM me: The Acidification of Sphagnum Moss Substrate during Phalaenopsis Cultivation

Decker's point was that if you repot long before the bark has started to decompose then you can repot without disturbing the plant. So there is no point to go longer (unless you have so many plants that it is a burden to repot every year).

Orchiata is a pleasure to work with, in my opinion. I have always had to soak my bark mixes and rinse them to get rid of nasty stuff in the bark, but orchiata is good out of the bag and breaks down VERY slowly.

I use the super course + perlite/hydroton for cattleya orchids, the medium grade with perlite/hydroton for dendro's, and the fine grade with perlite and sphagnum for paphs and phals.

It's a lot more expensive, but it lasts so much longer that I can justify it.

Glen is a great paph grower. I had the privilege of sitting in on one of his talks at the cape and island orchid show a few years back. Unfortunatly i lost most of the paphs i bought from him due to a fire in my house. But the few plants i have left are doing amazing.
That being said, the best i can remember from his talk was that he used organic fert. the decomp with organics is a bit faster than with chemical, based on my experience. So repotting often would make sense.
However i disagree with him about how often a paph should be repoted. Though paphs don't show much stress from repotting and seem to handle it well. I believe repotting a paph should only be done when the media is no good or it has out grown the pot.
With that being said Orchiata sounds like a great media for paphs.