Not sure about the 'red bag' but you added concentrated fert to the soil? Potentially problematic
If you use distilled water, you MUST add calmag plus.
Built-in drip trays can lead to soggy, anaerobic conditions in the lower part of the pot. Best to remove those.
Check pH of runoff. Without minerals from tap water, there's much less buffering and you can see pH drop off fast.