Lymnobium Laevigatum very slow

[hypnogogia]

My Lymnobium used to multiply really quickly, to the extent that I had to harvest it on a weekly basis. I haven't changed my fertilisation, but it is growing much more slowly now. Still has good colour and not showing any nutrient deficiency that I can tell. Any thoughts?

 

[Wolf6]

Was it benefiting from sunlight somehow which is now getting less? Or have you otherwise lowered light intensity? Has plant mass in the tank increased?

 

[hypnogogia]

Was it benefiting from sunlight somehow which is now getting less? Or have you otherwise lowered light intensity? Has plant mass in the tank increased?

Light has stayed the same and they weren't getting sunlight. My plant mass has probably increased slightly as some of the Amazons have developed larger leaves. I'm already dosing full EI, should I increase that be cause plant mass has gone up slightly?