I got twoIBC's. One for (what I like to call 'RAW' water) I collect from my roof seeing as how I'm on a water meter. Then the other is the 'PURE' tank which I have on two course of breeze blocks which the RO runs into.
I put the whole thing in a shed to keep it from the algea problem associated with sunlight. (or rather built the base, put the blocks down, mounted the IBC's and then built the shed round it all.) The only down side is keeping the 'RAW' tank topped off if it doesn't rain. Have considered some sort of electrical cut out so the pump doesn't run dry, even though the pump is said to be safe should it run dry.
I really should post some pics, if only to have someone say I'm doing it wrong.
As far as cleaning them out goes, Yeah it's a faf on. depends if you have the money to spend on new. I didn't. And I guess I already had a good idea of what I wanted and how I was going to get it. BEWARE of IBC's that have had the 'ADBLUE' which is used in commercial vehicles now. It is basically a synthetic version of urea (Pee for short) The vehicles use it to reduce emmisions. Jet washing, scrubbing, sloshing, then half filling with pure and sloshing around at least twice should sort it. There speaks the voice of experience. Also, after it's all set up, never fill the pure tank to overflowing as you'll never really clean the inside top of the tank properly. shame to waste all that pure by over filling.