Did them before i picked up 6x festea today to grow out we usually do them sat or sunday... Otherwise i do them on mondays when my mom comes and takes our kiddos to the park. I try and do the. On a weekly basis but haven't had grow outs in awhile so haven't felt bad if we missed a week on the 120. I'll be doing them ideally wed/sun on the grow out tank/s once again. But kiddos are older so i can sneak them in during the week.