| Sandra
To answer your questions, I used to use expanded clay (aliflor) exclusively for dens and Cattleya. I did not use a water reservoir but liked the clay for growing outdoors in Florida. We can have 4-5 inches of rain every week during the summer.
The benefits were that it could dry out much faster.
A big disadvantage was the movement of the plants to shows knocked a lot of plants out of the pots. Too much movement causes the roots to rub against the stones. If they were re-potted each time everything was OK but sometimes the plants would be knocked out of the pots by the automatic sprinklers and go a week or more without being noticed.
I do not think these are problems you would have.
For a hobbyist, the biggest advantage is the elimination of guessing how much water to use and how often. I really like Phals in true s/h with a water saucer and clay pots. You can see the water in the pot by the water in the saucer and when the saucer is empty you can watch the clay pot lighten as the water is used.
S/H will move water evenly throughout the pot. This is a big plus with Cattleya.
Everything works and your asking me this question made me realize I change my medium often not because of the plant's needs but to adjust for the type of care I am giving my plants at the time.
When I can control water every day everything works well. I use a drier mix in summers during the rains and a wetter mix during our dry winters.
I always recommend to chose the medium that matches your method of caring for the plants.
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jerry  |