About 1 month ago I moved into EI from a very lean regime. My plants used to grow pretty well, but not "really" well... So I tried EI fertilization, and despite most of my plants improved growth, some plants such Alternanthera and Rotala got worse. My Ambulia instead, had already some issues probably with the substrate, and so far it hasn't changed much, it has a very slow growth compared to how much it used to growth a few months ago... Anyway, Alternanthera lost most of the leaves, and now is putting out new leaves (smaller!), and so hopefully it is just adapting to the new environment.
What instead really puzzles me is my Rotala Rotoundifolia. It used to grow pretty well (not very well though), then I moved into EI to improve my overall plant health, and instead my Rotala turned dark, stunted growth at the tips as well as twisted growth. Also, some leaves turned a little translucent. At first I thought was a lack of micros, so I increased them without any difference... After 1 week I realized that I was probably dosing too low KNo3 because I was relying on the color chart of my No3 test kit, whereas with a reference solution I found out that I needed more No3... so I increased that to reach a level of at least 30-40ppm a day to overrule any possible Nitrogen deficiency. All other nutrients are slightly in excess, I have also increased my Co2 to have a PH drop of about 1.2 which should give me 30-40ppm of Co2 (drop checker is,lime green, almost yellow)' but after 3 weeks my Rotala has not improved, it is stuck, here are some pictures of it:
Note the tips of the last picture: they just don't grow! Even if I cut the stem at the top, the re-growth is stunted!
Some info about my setup:
- 75gl tank
- Wet/dry filter sump 2000l/h via Eheim compact 2000
- Co2 injection via am1000 with return to sump via independent Eheim 1000 pump
- PH drops from about 7.4 to 6.2 during Co2 peak. Co2 starts 2 hours before lights are on and turns off 1 hour before lights are off
- Lights: 4 x 40w T8 tubes, 8 hours a day.
- GH 16, KH 7
- EI dosing according to what suggested on http://rota.la
for a 60gl tank since I have medium light. I alternate macros and micros every day.
- Water change: since I moved into EI, I begun changing water 50% once a week, but in the last 2 weeks I have increased that to change 50% twice a week to see if that improved the Rotala. No luck so far...
Did I forget anything?
I am eager to know your thoughts on this.
Thank you in advance!