>> I changed my potting medium to a very chunky, fast draining mix (a combination of potting soil and lots of orchid bark mix,
For a long time, pure "orchid bark" was the only way I could find evergreen bark that was clean and dry. The price is about the same as shredded $5 bills, but it drains faster and lasts longer.
Then I found a Lowes that carried "Fine Pine Bark Nuggets", around $4.20 for 2 cubic feet.
Also, a fancy nursery that had evergreen bark SHREDS that were clean and very nice, but around twice the price of Lowes bark nuggets.
I screen them with 1/4 galvanized hardware cloth, but I need to buy some 1/8" mesh. I try to get rid of bark dust and powder, then add just a little peat-based potting mix, for water retention.