• Looking to buy a cephalopod? Check out Tomh's Cephs Forum, and this post in particular shares important info about our policies as it relates to responsible ceph-keeping.



Pygmy Octopus
May 30, 2003
This question is not about an octo tank. After the death of my six month bimac I decided to test my ability to keep a reef tank. There seemss to be an abudence of advanced aquariests at this site so I thought I'd throw the question out. Now it may seem like a stupid question but what is the difference between metal hallide lights and hallogen lights. The self contained MH lights that have two sided bulbs look almost identical to the hallogen light that mounts on a stand. Would the hallogen lights work? Do they have the right light spectrum? Do they simply get too hot? It seems Im clueless in this area.
I'm not that experienced in HOW the lights work, but I'll tell you one thing: METAL HALIDES ARE BRIGHTEST. I HAVE YET TO SEE LIGHTS AS GOOD AS METAL HALIDES. HOWEVER, It depends on what kinda things you want. If you want to keep the lights for your next ceph, get somethin else. METAL HALIDES WILL DAMAGE A CEPH'S EYES. SEVERAL PEOPLE HAVE KEPT OCTOPI THAT TOLERATED MH LIGHTING, BUT IT ISN'T GOOD FOR THEM. If you want acroporas, velvets, birds' nest corals and the like, you MUST HAVE METAL HALIDES. (especially ACROPORAS!!!) Many corals require them. However, if you aren't willing to spend upwards the $500 mark, I'd recommend going cheaper. The combined cost for a good MH fixture with the other stuff (things that need it plus the other stuff they need, and the electric bill) is extremely high. For example as to how bright it is, I have a 90g reef tank with 7 65W PC lights (4 10,000K and 3 20,000K)(450W total) and a simple setup of two 175W MH lights in the same model tank is almost twice as bright. More details as to what you want to do with the tank and I can help you more.
10,000K and 20,000K (preferrably ACTINIC BLUE) are the most highly recommended colour temperature for corals, BTW. More info is more easily found on reefcentral.com in the sps forum and other coral forums. If you want acroporas, the general concensus there (and anywhere I've gone so far) is that MH 10,000K and 20,000K are the best.

BTW colin, sorry, I was a little unclear as to what I meant. :oops: I meant I don't understand how they work as in schematics, etc.
Does anybody know what light spectrum/temp an octopus would be most suited for??

All's Ive ever heard is that you dont need much and its up to yourself in aesthetics.

Before you answer thou I know not all will be the same but we'll take Bimac for instance since thats what most keep.