Baffled by Holes in Red Tiger Lotus Leaves
So I suddenly started getting holes in my RTL leaves about 4 days ago. They have been and are still growing like crazy but the holes make me think that something might be wrong. Some holes appear overnight while others start out as green patches. (See pics)
Everything I read seems to point to holes being caused by Potassium deficiency. However, I always add potassium and both of my plants have several osmocote root tabs under them which I put in about a month ago. This makes me think Potassium deficiency is extremely unlikely since none of the other plants show symptoms and even if there wasn't enough in the water, they would be getting enough from the root tabs.
What else could be causing holes to appear suddenly?
Here are my specs:
55g fairly heavily planted with laterite substrate
DIY CO2 (giving around 25 ppm) +excel
Dosing Seachem Flourish, Equilibrium, Nitrogen, and Potassium
Fish are: Angelfish, Serpea Tetras, Black Tetras, Buenos Aires Tetras, young CAE's, 1 Krib, 1 Red-fin Shark, 2 Pearl Gouramis, 2 Kissing Gouramis