I remembered that I had some seachem root tabs from a while ago and stuck one under the sad plants. It's been about a week and I'm already noticing a huge turnaround in the plants. Where the macandra was hanging on for dear life, it is now reaching for the lights and sprouting new shoots. Even is becoming red for once. Nanjenshan is finally getting out of its stunting and growing bushy again.
sorry I couldn't respond that that line in your post earlier. However after looking at the Seachem web site you shouldn't need to try adding any Calcium sulfate.
Seachem root tabs contain Calcium, sulfur, chlorine, and cobalt which are nutrients that are missing from the Nilocg. I would expect continued rapid growth while the plants use up some of the excess Nilocg nutrients that the plants couldn't use earlier. However as nutrient levels start to stabilize plant growth should slow down somewhat but still at a rate faster than they were before adding the root tabs.
Phosphate levels should now come down now without any extra water changes. I don't know how much phosphate is in Nilocg but I wouldn't be surprised to see the phosphate level stabilize at 1 ppm. Nitrate should also drop some. I generally try to keep it below 20 ppm due to some information I have seen that above 20 ppm it could have adverse effects on fish. But some people naturally have water with high nitrate.
I assume this means that not all plants need the same quantities of these traces.
I assume the the same thing. But I have found no studies regarding this using common aquarium plants. However I do know that algae can continue to grow when most plant cannot get enough nutrients in the water due to a nutrient deficiency. So algae appears to do very well with very low nutrient levels while most plants would struggle.
Some plants probably get most of their nutrients through the roots, Others mostly through the water column. Others are probably a mix of both. Again little information available on this.