What is it? I have notice that lately I have some pink stuff growing on...

I have notice that lately I have some pink stuff growing on the sides of my aquarium. I have to take a blade blade to scrape it rotten. What is it ? How do I keep it from returning?
Does anyone own a hint more or less...
Answers:    Is it a saline water reservoir? It may be coraline algae. Its growth is the sign of a health established reservoir. You just own to deal beside it. Even a perfect cistern takes lots of upholding and cleaning.
What is the price for one ton of...
sounds like marine mold to me, you just have need of to clean your cistern more often