So, I have modeled my tank off Burrís setup with black diamond blasting sand and dosing plan, and I have a journal of it here: https://www.plantedtank.net/forums/12...high-tech.html
Things were going pretty well with using CSM+B for traces, at 0.015 ppm Fe. Most plants were growing well, but I wanted better growth from Ammania Senegalensis (which had some stunting) and Ludwigia Glandulosa, which grew very slow and would lose more lower leaves than other plants. I keep lower light than Burr Ė I havenít measured it but I would estimate itís at 60-80 PAR at substrate.
Wondering if the EDTA chelator was building up and holding me back, I decided to get Flourish Comprehensive, since it had a long list of micros, even those that arenít mentioned that often. Doses were per the instructions, which would be in the ballpark of 0.015 ppm Fe from CSM+B, but different ratios due to its mix. Results were bad Ė after only two doses I saw new stunting in AR and more stunting in A Senegalensis.
After trading notes with Fablau, he pointed out that the zinc in particular is very low in Flourish Comp, and that itís really meant to be dosed along with Flourish Trace. So, I got some of that, and it made sense that I was probably low on something in my tank. It couldnít be trace toxicity, even though the symptoms were there, and they happened 24 hours after dosing. The amounts I dosed were just so small. The past week I dosed Flourish Trace per the package instructions, along with pinches of DPTA iron. Zinc amount would be similar to 0.2 ppm Fe from CSM+B, so that would rule out any zinc deficiency. Overall results were awful. Stunting in nearly all AR stems, and new stunting and shriveled tips in Ludwigia Glandulosa. I saw this even 24 hours after the first dose of Trace. I doubled down on the Trace two days later, thinking I can always undo it with a water change. More bad results. Keep in mind I have my light lower than itís been in a while, and pH has been 6.3-6.4, dropping from 7.5-7.6, and I also did a large trim a week ago to remove biomass and improve flow.
Then I thought of something Ė when you look up Ammania Senegalensis, many listings say it likes soft water. I had been getting away from my usual Calcium dosing in attempts to use softer water and get it growing again. My tap has nearly equal parts Ca and Mg according to the local water report, and once I asked a local aquarist what our ratio was, and he said it was actually 3:1 Mg to Ca. Maybe it varies, and sometimes leans heavy to Mg? We have also had recent flooding in the area, which could have dropped GH and Ca even further (water reports show GH normally at 5.5). So, without doing my normal weekend water change, I added a big dose of calcium and chose to wait a couple of days to see if the AR and L Glandulosa unravel and start growing again, and if A Senegalensis starts looking better.
What Iíve learned through this is that I probably donít even need traces at 0.015 Fe Ė I have less light and biomass than Burrís tank, and Iíve seen results get worse 24 hours after trace dosing, even with different sources and pretty small amounts. In theory 16 ppm Ca and 15 ppm Mg should be fine, but it appears that in my tank, extra calcium gives you more margin of error with trace dosing, so I will keep adding 10 ppm or more with my water changes. I also learned my previous regimen of adding 10 ppm calcium with water changes, and CSM+B at 0.015 ppm Fe probably was pretty good to begin with.
I will be doing a large water change tomorrow before a summer vacation, so Iíll report back on how the tank is doing a few days after the big Ca dose.