Stagnant water???

[prosnow]

okay, i was wondering if i filled up a 150 gallon tank with RO water and just put a bubbler in it, would it be fine for top ups and water changes?

i'm only setting up a 35 gallon cube tank, so i dont think i will need to add much for a top up,

but i was just wondering if the water would become stagnant from just sitting there,

anyone that does this now or has in the past, please let me know your thoughts...thanks