Are you sure it is calcium? Post some pictures

 

Now I'm not totally sure what it is, but it has a crusty texture and it is light green in color, maybe whiteish

it could even be an algae I don't know.

 

Biogenic Decalcification

though with the stuff on the glass, I'm not quite sure..

 

According to what I'm seeing, dwarf saggitaria might be able to do this reaction too. After I searched "Biogenic Decalcification" I heard someone say "algae is more efficient than most plants at (biogenic decalcification)," so maybe that's why it is encrusted on the glass. Interesting.


This reaction can increase PH- I have a good amount of valisneria and I don't want the PH to get too high. My fish are looking healthy still, so that's good. It's been going on for a while.

I might have to consider either reducing lighting or adding CO2. I wanted to have this tank as low maintenance as possible. Has anyone ever experienced any real problems from this sort of thing happening?

 

I had something like that in one of my tanks in the past. But it was only on glass corners and surface where glass meets the gravel. Never on plants. And It took a good 6+ months to develop. I always thought it was just calcium deposits as my water is very hard (20 GdH) and the green tint was just algae film growing on it. Never had it on any other of my tanks though... This one was med-high light without CO2 and daily Excel as carbon source with DHG as only plant.

 

Im not surprised at all you are having such issues with 128W of lighting on a 40G and no CO2. Remove two bulbs or add CO2 perhaps? Do you have reflectors on?

 

I always see that happening on the Vallisneria leaves in my concrete pond.