The general rules and limits change :
NO snorkel, gloves, or knives
max 4 divers per guide
no decompression diving max distance to open water : 67m/140ft-keep
your light must be on during the entire dive
never pass under the guide line
no restrictions (area big enough for 2 divers to pass side by side)
always maintain a continuous guideline to the surface
follow the guide in a single line
keep your position and stay at least 1.5m /5ft from the diver in front of you
dive in horizontal position, bend your knees and use the frog-kick finning style