Ro-Di water storage

I have 2 fiberglass cylinders one that holds 45 gal (Di H2O) and one that
holds 25 gal (Ro H2O) I bleached these tanks out for days and rinsed them
thoroughly, one week after storing H2O in them the Ro tanks H20 has such a
musty smell and taste, we cannot drink it, the Di tanks water smells musty,
I do not try to store more than 10 gal of Ro H2O or 20 gal of Di H2O at a
time unless I am going to do an H2O change (Di H2O).

Any suggestions? would a little peroxide help????

TIA,

Reaper