I haven't posted here for a darn long time ._.
Anyway, colored attacks are awesome. Incoming nerd rant-ish thing. I remember you saying something about green rocks? You do know that rocks and dirt and stuff can be pretty much any color, right? In a way, ores are rocks, and copper ore is a teal-ish color. There's also likely tons more of green earth-y objects. Gems might also count as being a rock, and amethyst can be pink, I would assume. Heck, diamonds could be pink. Aquamarine has several different colors.
I'm also pretty sure someone said something about water only being a select few colors. Toa of Water can control almost all liquids, right? Not just water, I think. That certain yellow liquid probably doesn't exist in the Bionicle universe, so ignore that. Water is naturally clear, or green-blue. Or maybe the green-blue is because of the ocean floor. I'm not sure, but still. Anyway, if Toa of Water can control almost any liquid, couldn't they control, for example oil? Crude oil comes in almost EVERY color known. Crude oil can also be found under oceans, and if a Toa of Water manages to control a lot of water above the oil pocket, it would cause a current upward, possibly dragging sand and loose particles with the water, maybe revealing the oil, and the oil might mingle with the water, causing it to change color. Or I'm just ranting on about impossible stuff.
Someone also said that fire can be every color, I think. I'm not sure if that's true, and heck, everything I just typed could be false. Fire being every color could just be because yellow fire might be in front of blue fire, for example, giving the illusion of green fire. Unless the fire is cursed. If you get that reference, cookies for you. Again, I'm not sure about the fire. I wouldn't be too surprised if it can be every color.
And don't take this as me saying something like "you stoop bro," because I'm not saying that. I'm just saying that a lot of matter can be almost any color. As I've said a few times, I could be completely wrong about this. My knowledge of elemental powers is a bit rusty.