I HAVE had massive sand beds in 20 plus tanks for over a 40 year period and dont do water changes or touch my beds.There has never been a trace of red slime except when i tried vodka dosing.Barebottom large water changes are 1 way but so is a nice deep sandbed with ozone and no water changes.Aci doses chemclean regularly it is crazy to me to not use it the second you see red slime.If i had to do water changes i wouldnt have tanks.Its does seem like the sandbed guys like myself are a dying breed.