Food Coloring?

[fishmamma]

It's obvious that a blue light could have accomplished the same effect.

 

[HuffDaddy]

Not that dark. I have the room lights on and the flash from the camera. and I have an actinic light it cost about 100. The food coloring cost about 3.
I'm not saying that tinted water is the way to go. I'm not going to do this on my big tanks I just wanted to know if it was possible.

 

[Rmelz]

I used food coloring in my wc setup on my pc. After a few days the water was clear.