tricksterpup - I'm sure the number required varies with the individual, and perhaps with the complexity of the setups, but 4 sounds a bit light for prima facie diagnosis of insanity, unless they are demanding tanks - as, 4 reefs, no question!
With planted tanks you shouldn't, or can't disturb the substrate routinely. So that option is out for maintaining sand. My unplanted tanks have shallow substrates also, which are regularly and rountinely well-vacuumed to full depth.
With planted tanks you shouldn't, or can't disturb the substrate routinely. So that option is out for maintaining sand. My unplanted tanks have shallow substrates also, which are regularly and rountinely well-vacuumed to full depth.