So, i have a 5 gal bucket with citric acid(pH=2.2) which i keep in my garage and use for rust removal. I noticed some biological matter growing in it, like fungus or similar. My question is: will this growth consume my citric? And also, what can i add to citric to stop the growth? Just trying to keep it potent for a once-in-a-blue-moon rust cleaning jobs. Next to it i have a bucket with dilute sulphuric acid, used for the same purpose and that one is very clean. But i like citric acid better than sulphuric for rust removals. When i am asking for things to add to citric to stop biological matter growing init, i mean chemicals that are safe enough that they wont be harmful to me. I treat this citric acid as the "less-haz-mat" rust removal option. Wile being much more careful with sulphuric or phosphoric acids.