Crud build-up in my make-up barrel

[Junkzoo]

Today, as i was rinsing out my original water make up barrel(rubbermaid "safe" 34g garbage can), i noticed that i had a brown crud on the sides(been there for a while) as b4, i kinda just wiped it out, then rinsed.
i use RO/DI and IO in it, had the container for probably 6-7 yrs,always covered, heated and have a PH running in it .
looks to be a mineral deposit or something,,,,
don't worry about it or what? just was wondering if whatever it is,if it could leach back into the SW while it sitting,,,,barrel never it empty /dry, when it's empty,i'm starting to fill it again right after.
just wondering,,,
PS: anyone know of anything i could use to safely remove it?
i usually use a scotch-brite green scrubby pad to clean it ,never get it all,,,,

[Junkzoo]

I do have a newer 55g Rubbermaid "industrial container on dollies for my standard W/C's, the old 34g one is my original one i use now for back-up/extra water
i usually start adding salt when the water level is over the P-head,and add as the level goes up,,,,

[cath]

I'd like to know that, too!

Going to catch some shuteye, J...it's now officially Wednesday

[Doug1]

Jeff I am sure its calcium carbonate stuff preciped out from the interface with synth SW and room CO2. I doubt that its a problem, it seems to slowly build up over time when doing batch after batch of new SW. I have tried vinegar to get it off with limited luck, I suspect dilute muriatic would work better but i am not sure its worth it