I don't miss your point at all fishball.
I have 3 different planted tanks, all of them with various wpg as a guideline. Non of them have carbon being added either pressurized or liquid. ALL of them are dosed with fertiliser, ALL of them grow healthy and lush, ALL have NO algae what so ever.
So, from my experience, carbon wouldn't make any difference to my tanks other than to induce much quicker growth. Something that I am not really looking for. I am happy with steady plant growth that is healthy and vibrant.
Less to go wrong
Less to worry about
Less equipment in my tank
Less maintenance of plants (

)
Nothing against co2, the members on here who do use it have amazing tanks with amazing results, my moss carpet is probably a month behind ianho's, so there is an obvious difference, but I'm in no rush

I have all my life for it to grow in.
The op asked what was needed for a planted tank. He didn't seem fussed about co2, something we have been speaking about in several threads. Dosing a fertiliser would be a good idea. Adding extra nutrients is better than having no nutrients being added other than fish waste.