Bro Raymond, so u are the guy with yr kid at iwarna. Nice avatar. Speaking on personal experience, I do keep nsw for a month without aeration and use them. However, my tank is 4ft with 4ft sump. Hence the water chge is only ard 25l as compared to my tank of ard 800l. Therefore, the impact is not great. For small tank, water chge tends to have greater impact due to water volume. That is the result why ppl say big tank is easier to maintain as compared to small tank. For your reference.