Ughhhh, I remember when I got my piece new, it used to get this kinda slim on it and just seemed to keep coming back ALL the time. Just clean it off every few days, it will stop coming back, eventually.
ok, taken the pecies out and put them to soak in hot water for a bit. got 2 bm plecs in there and dont know if its harmful. hopeit doesn't come back too much
just scrub it in warm salt water and leave it to dry then put it back in i had to do mine 3 times before it stopped coming back not sure if its harfull to fish though as mine was cycling when i had it so didnt have fish in there
I had the same thing on my bogwood while the tank was originally cycling, I just scrubbed it off all the pieces and popped them back in, and all was fine after that