Corals with a dwarf octo?

[cadre]

So I want to get an octopus but I was considering getting a merc for my 18g (w/ 10g sump) before I go through the trouble of upgrading to a larger tank.

Can anyone tell me if these corals will be okay? I have milliporas, montipora caps, zoas, ricordea, palythoas, a colt coral and a chalice.

My main concern is the millies because I'm told not to keep sps with octos but can anyone tell me why?

Any other suggestions or input would be great too. I hope to upgrade to a 75g when I get the money but it will take some time. Thanks in advance!

[asid61]

Stinging corals will harm the octopus.
Non-stinging ones should be fine, but glue the rock together so the octopus doesn't bury the corals while rockscaping.

[cadre]

Stinging corals will harm the octopus.
Non-stinging ones should be fine, but glue the rock together so the octopus doesn't bury the corals while rockscaping.

Okay thanks. The only things is that I don't think of sps as stinging corals, so why am I reading that they do not mix with octopuses? And would hammer corals count as stinging because it's a very mild sting?