Hi guys, I've been doing a bit of reading on here recently, particularly djkaty's thread which helped a bit. I am a seasoned reefer, I've kept marine tanks for about 5 years now, so im pretty comfortable about water quality and such, and I do have my own RO unit which has made things loads easier! I was looking at carrying 30l of RO water back every week which would have murdered me, since I recently upgraded to a 300 litre aquarium - but this time I'd like to do something different, i.e. an Octopus! My new tank just has rock and corals with no fish. It's been going for about four months now but the rock is from my old 4ft shallow which was going for about 6 months prior, so its well established. A few things I understand would need to come out including my anemone and longspine urchin. I just had a couple of things I could do with clearing up before I go looking more into it. I also have x4 54w T5s which I see are far too bright for an octo, but was thinking of just changing these to actinics or ATI bulbs which give a blueish colour but still have plenty of par. In terms of water quality I often do heavy-handed water changes to keep things in check. S.G 1.026 Ammonia: 0 No2: 0 No3: 0 - Trace Phosphate - 0 - Trace pH: 8.1 (morning) - 8.3/4 (evening) My setup is a concern also. I am running my reef berlin style, which is basically live rock, lots of flow and a large skimmer. I have no sump. I have one large koralia pump which kicks out 12,000 litres per hour, is this too much and / or unsafe for an octopus? Is a sump really 100% essential? Which corals, if any, could I keep with an octopus? At the moment I have a mixture of LPS and SPS with the odd Ricordea and Red mushroom rolling around in there. The stinging stuff seems as though it would need to go, but I also have a massive toadstool in another of my tanks, could that go in? I wasn't sure on species either. I'd like something diurnal really. Even though the nocturnal ones look awesome, I've had lots of experience buying awesome looking things for my reef which I never see again! Any suggestions for an active daytime octo which is suitable size for my aquarium? I am not a believer in getting things that need upgrades in the future, as my experience working in the aquatics trade has taught me that people never, ever do it - and I have no space for an even bigger tank. Already got moaned at for getting this one. >_> That's all I can think of for now, but I'm sure I'll think of something. Any help would be greatly appreciated, because it looks like an octo tank is a whole new game. I read some of the articles, but any particularly informative ones that cover any of my concerns would be appreciated too. Suggestions for books would help also. :D Thanks!!