I have the same problem with this brown/black algae all over the leaves
The leaves start of well nice and green and healthy after a few weeks they
start to get the covering until they are completely covered.
My tank has been up and running for 2 years now and still getting the problems.
190L tank (but probably about 160L water in the tank with substrate, wood etc)
2 x 55W AH Supply Bright Kit
All water parameters are within what is recommended and I'm dosing as the EI
Plants are growing really well but always had this problem
I have an internal filter (because it was built in when I got the tank) and am using carbon sponge along with course and fine sponges. Someone mentioned that you shouldn't use carbin filters in a planted tank ? Anyone have any views on this.
I do know the phosphate content of my water supply is sky high
It's well off the scale of the test kits and I've checked with my local
water company and this is in line with what they put in the supply