How to delete blocks when standing on a block

[[Site & Server Ban] JensenBreck]

I am making a parkour map and want it so that when you stand on a sea lantern it removes or replaces a selection of blocks with air by putting a redstone block by redstone which activates loads of commandblocks which remove the blocks. The command I am using is: execute @a ~ ~ ~ detect ~ ~-1 ~ sea_lantern 0 setblock 33 5 8 redstone_block
Why is that not working?


I didn't find the right solution from the internet.

References:
http://www.minecraftforum.net/forums...ing-on-a-block


explainer video

[[Admin] markdf]

I have no idea what the command should be, although I assume you are not trying this on the server as its not possible.