bernabei
form the sounds of things, your levels never completely stabilized? the only way to be sure the cycle is complete is to monitor your parameters for 2 weeks after they come down, just because they came down, does not mean the tank is completely cyceld and ready. If there is any non live matter(ie. dead rock or sand or little gadgets people put in their tanks), then there is a good possiblity things will fluctuate for a while(even months), before they stabilize.(Beleive me, i went thru it once with a tank that i tried ot use dead rock in for decor and it was quite boggling for a while.) And if they are not stable, then it is not safe to add fish. and plant life may help, but it may also hinder things.
plant life is good, but should be used in a fuge, not the main tank.
But, if you have lots of plant life, it could be giving you false(not actually false, but inaccurate)readings. you want stability and 0 trites and ammonia too much plant life will brign it down ultimately but it also masks it thru the consumption. YOU WANT IT ZERO, even without plant life. That would be the goal you want to achieve. then the macros will be an added benefit and help with the trates and food source for you tank.
Plants are not a cure all and if used like this, would be the proverbial bandaid on the cracked damn. Fix the problem first, then build, instead of merely hiding it. Because hidden, it is still existant. This is not an out of sight out of mind scenario where out of sight would mean it is all good.