What causes my aquarium water to turn pink?

The water in my outdoor aquarium looks like someone poured a cup of fruit punch in it. It's pink. I clean it change the water and everything, but eventually it starts to turn pink again. I have four goldfish in it.

What causes my aquarium water to turn pink?
do you have red rocks? alot of times red rocks (poly resin) that has been dyed will bleed color if faulty or if old. if not it is possible that you have red algae growing in your water. Plants will help, water plants and shade plants along the outside of the tank/pond. also after a partial water change add a chemical algae deteriant, like "no more algae" by jungle or "algae destroyer" by API. These chemicals will be deluted as it rains or if you add water to your Aquarium/pond? So you will have to add more of the chemical. There is another alternate, depending on your pump for your tank/Pond? A uv sterilizer will take out the algae as your water is processed threw your filter pump. Check out petsolutions.com or dr fosters and smith.com to look at sterilizers and algae destroying products. good luck
Reply:mabe plants or sompthing around it fallin in ???
Reply:It's the type of algae growing in the water. OR you have something red in the aquarium that wears off into the water....but I'd bet it's algae.
Reply:it's outdoor right?? Does the rain get into it? I heard that rain water will do it, same sort of thing happened to my kids wading pool..
Reply:Pink Algae - it requires a specific treatment - see your local dealer
Reply:Too much red food colouring in the water?
Reply:stop feeding dye-colored fish foods/ pellets.
Reply:I have an aquarium but never seen the water turn pink might want to test ph if you havent hope it turns out
Reply:Pouring fruit punch into your aquarium will do it everytime. Geeze, what did ya think would happen?