Water in canister has brown stripes

[chs724]

i mixed saltwater a month ago and kept it in the canister to use it for waterchanges. i forgot about it and a month later it has brown like spraylines and dots on the bottom of the canister. i only use rodi water therefore i wouldnt know what is growing in there. has anyone any idea whats goin on. thx

 

[Randy Holmes-Farley]

i mixed saltwater a month ago and kept it in the canister to use it for waterchanges. i forgot about it and a month later it has brown like spraylines and dots on the bottom of the canister. i only use rodi water therefore i wouldnt know what is growing in there. has anyone any idea whats goin on. thx

Which salt mix? Some may grow bacteria due to including organics that they may consume.

But what you are seeing may also be simple, ordinary precipitation of calcium carbonate.