I use IO but I happened to jack my cal skyhigh w/caribsea+ so I went to the purple bag for awhile. I also get nasties w/ a pre mix of a day with IO(too much settlement). It is available to mix in 15min. No need for 24 hours. Disolve w/ warm water and the rest is ro/di for me. No need to change, plus it is basicly all that is avail. w/out spec. order here.