Time for an update...
Things are overall looking pretty good. I'm two months into remineralizing almost straight DI water. I did this thinking maybe there was a problem with too much sodium and/or chloride. While there were some definite improvements that seem to be sticking with me, There are still a few things not looking their best. Plus, iit seems
@Pikez has way more of both Na and Cl in his water, and seems largely untroubled by it. So I'm not sure why things improved -- I am remineralizing back up to what I was doing before, just minus the sodium & most of the chloride.
The things giving me trouble are concentrated on one end of the tank. Coincidence? This end gets first shot at the CO2 and flow pattern, nothing is too crowded, no shading problems between species, etc.
The good news here is that L. glandulosa is largely holding onto its improvements. The random gross stunting seems a thing of the past, all the plants are uniformly doing the same thing now. Still, leaves are a little wavy.
Acmella is still kinda challenged. Leaf shape is better than it was, but there's still distortion, and some deterioration of older leaves.
AR is growing well, but leaves remain wavy at best, with a couple of plants showing worse distortion.
HC has never really taken off in this system. Growth has been unimpressive, and there's BBA in there. It has spread a bit and shown some signs of promise, but remains slow. Something is ... off.
Then there's the good side. Everything seems to be better here despite the lower-flow. Things remain good though I let this side fill in pretty well.
So, why? This tank gets straight up water column dosing, rich macros, and seemingly moderate micros, similar to Burr's mix, but probably a bit richer -- iron at about 240ppb per week, Mn at 110ppb per week, etc. Concurrent with the switch to almost full DI water, I've backed off some on my water change volume -- still weekly, but 33% rather than the 55% I had been doing regularly. This might be leading to increased concentrations of nutrients building up. Other than the few species bugging me that pretty much always have been bugging me, everything remains good.
I had thought about working some Osmocote plus into the sand when I set this up, but opted not to, just to try fully inert substrate for a while. Am I missing something?
@Pikez 's results in his Kill Tank thread have me thinking about backing off the water column and using some of that Osmocote...