Yea, that site is really great! There's a pest/disease section, that has tons of pics, and prevention/cure advice, that is really helpful... If you didn't notice it
Basically, with Den-Phals, they like to be watered often, and dry out fast. So, depending on how frequently you would like to water (or, have time to water), use that info to adapt its cultural needs, to your conditions. ie. if you wanna water daily/every other day, use inorganic media (LECA, lava rock... etc - that dries out fast), if you'd rather water on more of a weekly basis (*your conditions r different than mine, so your mileage may vary on the timing of your watering*), then use bark, maybe with some sponge rock added to it as well.