Ph, Co2, and black spots on Java ferns, buffering?

[Profector]

So my java ferns are getting black spots. From what I've read this seems to be a common problem with diy co2 setups because the co2 isn't steady. However I have bottled co2 that's had a very steady bubble count for months now, and I'm having the same problem. Can anyone tell me if is really of varying amounts co2 in the water is the cause or perhaps it's the change in ph caused by the co2 or something else? Everything in my tank is doing good except those ferns. I'm starting to think that after the lights go out the ph changes and that maybe the cause. Or perhaps the water can't buffer the ion exchange and so the ph swings and the javas freak out. I'm just making guesses. I was thinking about getting a ph controller, but I don't know if that the right answer if my water isn't buffering correctly. Anyone?

[The Trigger]

Java ferns will grow fine if youre not injecting ANY co2, so that's prob not the problem. I'm thinking its one of two things. 1. You have the rhizome buried and that's killing it. Must be attatched to driftwood or rocks or just laid on the substrate. 2. Your lighting is too intense on the fern and its burning the leaves. I found if you have the light too close the waters surface and the leaves are high up it will burn the leaves.

[The Trigger]

Also java ferns grow wierd roots out of their leaves which produce baby plants. A lot of people mistake them for BBA or staghorn

[Profector]

These are fairly new plants. I had bought one from the LFS a few months ago. Soon as I got it home I clipped all of the leaves and tucked them amongst some drift wood at the bottom of the tank, a couple did get tied down with nylon thread, but there isn't anything in or on the substrate. They all start to grow fine, but they eventually get the black spots or bands. It's not the same type of spot the leaves got just as they started to produce the baby plants. I'll take a closer look in the morning after the lights turn back on. There is a section that transitions from full light to heavy shade, perhaps I'll see the one's with more light are the ones with the black spots.

[Hoppy]

What size tank, with what lighting are you using? What brand of light fixture too?

[Seattle_Aquarist]

Hi Profector,

Do the black spots happen to just a few leaves occasionally or is this happening to a majority of the leaves over a week or two period?