The pot is to small, it has become root bound, others may have other thoughts, good luck it is stunning !!!!

As an aroid fanatic, I just love this! Stunning.

Water meters don't measure moisture levels. Pour some distilled water in a clean cup, clean the probe, and stick the probe in the water and witness the fact it reads "DRY". Now sprinkle some salt in the water and watch the meter go to "WET". Sans don't tolerate wet feet well at all. It would be better to allow the soil to go completely dry before watering and suffer the drought stress than to water when you can still detect moisture with a finger and lose the plant. I'm not advocating for allowing sans to go completely dry before you watering, just establishing the lesser of 2 evils would be to let the plant go dry. This is a god time to rerelate a story I tell from time to time. I was a silent observer during a workshop being conducted by Japanese bonsai master, Ben Oki. A lady was working on pruning the roots of a juniper when she asked, "How often should I water my plant?" With a stone face he replied, "Wait until plant become completely dry; then, water day before." Mr. Oki had a dry sense of humor, so I was never able to determine whether he was trying to be funny or if the reply had something to do with the fact that English for Mr. Oki was a second language. What I do know is, he didn't smile or look up from his work to see if anyone understood what would normally be seen as a clever play on words; that, and the fact his advice was and remains spot on. It fits your situation perfectly - water the day before your plant is completely dry. Al

From what I remember, (which is not much these days) is that Zeylanica is a special species and not very attractive and not much grown anymore and what is called Zeylanica is really just trifasciata. Why the old name sticks is unknown. To get the best colors of Black Coral it has to be grown well. In direct sun. If kept in the house all year it tends to darken and get washed out banding sort of. I used to see it at Lowers a few years ago but not in the last few years. I guess it comes and goes. I do like it over plain trifasciata. Was going to buy it but was too large and the wife was with me. She would have had a fit.