I downgraded from 125 to 40 gal. I had 125 mixed reef tank for last 10 years so maybe my question sounds stupid. I consider myself experienced reefer after all those years but I have one question. I always mixed water for 2 changes. I used 55 gal of water and use it for 2 water changes. After using half of the water remaining was left for 3 weeks with our aeration. Then before another change I plugged pump 24 hours before change. I never experienced any problems but I know some keep saying that we should aerate water all the time. Im asking because now if I mixed my water it will seat for a lot longer since it will be enough for 3,4 water changes instead of only two like before. Do you think that will be a problem? Thanks.Art.