Backyard Aquaponics
A place to discuss aquaponics

I am gathering things to make my first system.

I got a number of IBCs some had Potassium Hydroxide in them and some had Potassium Acetate in them.
What cleaning do i need to do before I use them.

Yes it is safe to use those. Both compounds are water soluble. Potassium hydroxide is used for soap. People will even add it to their system to bring the ph up. Potassium acetate is a food ingredient. Be careful with the potassium hydroxide as it can burn.

IBC Tanks that contained Caustic soda - are these safe to use if steam cleaned?

Caustic soda is Sodium hydroxide, or better know as lye. You can clean the tank with vinegar but it does cause a exothermic reaction so be careful. Wash it with water first and then neutralize it with vinegar.

And make sure you wear personal protection while cleaning it out. No ones like getting burned.