Crayola colored sand trials

I was looking to switch my tank over to sand and wanted blue sand to go with my decor. After looking at colored sand prices I experienced sticker chock. I stated searching online to find cheap colored sand that would be safe for aquariums. I found a few threads on forums about crayola play sand. There were several threads that had statements from crayola on the process of coloring their sand (Heat bonded) and also on its safety. On those threads a few members tried it and deemed it a sucess and that it was safe for the fish, so I tried it. I got the blue sand and was impressed when washing it. It was very clean. I love how it looked once in the tank as well. It is this brillant deep blue color and really gives the tank some pop. I have had it in my aquarium for about 11 months now and my water chemistry has never been better. Since I have had sucess in that tank I decided to change another one of my tanks over to colored sand. I changed my Piranha tank to green sand which was also visually appealing since the color scheme in the room it was housed in is brown, cream, and green. The tank is an oak tank with a canopy and the green went perfect. I changed the tank to the sand maybe about 3 or 4 days before I went out of town for the holidays. When I came back about a week and a half later my tank was cloudy, with a greenish tint. I thought maybe it was algae mix with the fact that the tank was dirty since it was overdue for a water change. I did the water change and by the next day it was green again. My friend who was in town said that it had to be the sand, that is what I was thinking as well but was hoping it wasn't. I did two big water changes the next week and the same thing happened. The fish all appeared in good health and actually seemed to prefer it since of course piranhas like murky water, so I decided to let it go for about a week and a half and my tank became very cloudy with a relatively dark green color. I did another large water change a couple of days ago and now it is staying pretty clear. The sand is still green, but it appears that it is not as bold as it was when I first put it in there. I wanted to post this on here so that anyone who had thought about using this sand could reference my experiences. Also I wanted to see if anyone would have any other theory on the green water or was it just the sand bleeding. My theory is that the blue sand is totally safe and works well with water and that the green bleeds for some reason. As for the pink or purple, I have read from others that they work, but I plan on testing them myself in the future. Where I am getting confused at is why is the sand still green if the color was bleeding off?

joe jaskot said:

Put some of the green sand in a jar with water and keep it in the dark. If the water turns green, then the sand is giving off some of its color. If the water is clear, it may indicate a green water algae problem in your tank.

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I am going to try that. Its just weird that the blue never bleed, but the green did. Maybe it is just algae.