Thanks. I may be able to offer some suggestions.
First, I would change the blasting sand. This is rough, it is intended to be abrasive as it is "blasting" sand. You mention kuhlii loaches, they would not fare at all well with this sand, nor would any substrate fish. Sand is ideal as a substrate, but it must be either aquarium-intended sand or play sand. I use the latter, it is very inexpensive, looks natural, and is completely safe. And plants grow well in sand.
Light. Duration does not compensate for intensity. Photosynthesis is driven by light intensity and spectrum, and the intensity is specific to the plant species so we can have high light requiring, moderate light requiring, and lower light requiring plants, generally speaking. Extending the duration if the intensity is insufficient will not help the plants but will encourage problem algae. If you are not intending diffused CO2, then i would go with moderate light. For one thing, fish do not like overhead lighting, so less intense will always cause them less trouble. And with moderate lighting and suitable plants (there are many), nutrient dosing can be reduced to balance, and that too helps fish. Every substance added to the aquarium water gets inside the fish, and while many may not kill them outright, it does affect them negatively.
EI involves adding excess nutrients for the plants, more than they can possibly use, and then removing the excess with a substantial water change once a week. Problem is, that the poor fish are forced to live in this soup and it does impact their metabolism and physiology.
Carpet plants need brighter light than many other plants, depending upon the species. And with increased light comes increased nutrients to balance to keep algae at bay and benefit the plants.
One can have heavily planted tanks that consider the fish first, which is my approach. Hope this provides some info.
