When this happens to my Glosso it usually means that it is time to change bulbs.
But it could be an iron deficiency too. I routinely over dose on the Flourish iron - a bit. And I also have Flourite as a substrate. So in your case try dosing iron. Another thing my Glosso really likes is phosphate. It responds rather quickly when I up the phosphates.
- 2 Eheim 2217s
- 4 Rio 50s - 4X96watts CF - Flourite - 2X300w Visitherm - Pressurized CO2