Thanks Stella... I was hoping for something a bit more definitive
LOL funny guy
It did start to worry me because it sprouted everywhere, proliferating on all the plastic hitches and sponge intake! I'm just curious why something is growing Now, after 4 years of failure... and no husbandry changes. Except I did collect some water offshore a few months back, instead of my normal beachwater...hmmm, maybe it favours low light, as one of my old bulbs died...and cold water. I'm using same water in my troppo, but no sign of it there.
Ah well. I AM enjoying it, whatever it is. I just like to Know these things