Hi. Your Nutrient rich Substrate will give you a good start but, depending on the amount, size and type of plants, it will run out of nutrients. My best guess is between 3 and 6 months.
I use seachem root tabs for my crypts and seachem Flourish comprehensive liquid for the water colour feeders such as miss and Java Fern. There are cheaper products but I like these. They are effective and o have read on here that some people have had ammonia spikes after using cheap or home made root tabs. I have never had that with seachem, but they're not cheap.
Ideally with a high level lighting system you should have a carbon source. Liquid carbon is good. Co2 gas is better but more expensive to set up and can be tricky if you overdose (the fish will suffer with excessive Co2). It's hard to overdose liquid carbon. Again, I use seachem Excel, they must be making a fortune out of me ?.
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