The cories are still getting sick, don't know why. Disorientation and difficulty swimming, sometimes death. I'm down to 8 but another one is looking bad. It's weird because all the rest of the fish seem fine including the other cories.
Despite that, I think the tank as a whole is getting healthier and healthy. One thing that I suspected was harming the cories were my co2 levels. Whenever I got a surface film the CO2 would spike a bit, and the ensuing water change would very quickly lower it. I can't imagine this cycle was easy on them. So I went ahead and modified the filter input to be a skimmer. So glad I did, surface is always crystal clear now. The tank also outgassed CO2 way more quickly now. I'm running about 3x as many bps to maintain similar levels. In this case the extra outgassing is exactly what I needed, before the tank didn't really have a mechanism to protect against CO2 buildup so this helps stabilize the CO2 level. I imagine that if CO2 was being kept in, oxygen was also being kept out, so the water is probably better oxygenated now too.
I noticed that my heater was reading four degrees too low, so what should have been 76 degree water was actually 80. Corrected that and now the water is solidly at 76 degrees.
The hydra have almost disappeared in the last few days. I don't think the like the additional flow. The cories' flashing seems to have lessened too, and while I can't really say for sure, in this case I do think they are related.
About two weeks ago I tried out making my own root tabs. Forgot to post about it sorry =/. I used osmocote plant fertilizer and empty gel capsules for delivery. I spaced about 10 of them out throughout the tank and under the plants I thought would benefit most. They really seem to be working. The crypts especially are growing way faster than I've ever seen a crypt grow. Today when I was doing my water tests I pulled an additional water sample from the substrate using a syringe and tested that for nitrate and phosphate. The levels were significantly higher, about 15ppm and 1.5ppm in the tank, and 100ppm and 10ppm in the substrate, Awesome! In the pictures I included shots of my two grouping of crypt wendtii green, all of the growth is new in the last two weeks since the melting (they were new with the cories).
I've got algae growth almost entirely under control. I still get a little bit of gsa on the anubias and a little bit of hair algae on the fissidens. The lilaeopsis maritiana however is giving me trouble. It just doesn't grow much and it doesn't look healthy. It is slowly spreading out but it just doesn't look all that great. Now that co2 and nutrients are stable, I think I might trim it way back and see if it come back pretty. If it doesn't I may just replace it with another plant, I'm thinking maybe eleocharis parvula, I really like the more delicate looking blades. I'll probably order some new plants this week to help fill in the tank a bit, I suspect it's a bit under planted right now.