Heyyy I'm new here, everybody give me a big hand! Truly, I wish this site had been here a few years back when I had my bimac. It was my first ceph, practically my first saltwater tank, and octo information was hard to come by - thus, I probably wasn't as prepared as I should have been. Anyway, on to my question: How absolutely essential is an RO/DI filter? Has anyone successfully kept cephs without one? How can I find out what's in my tapwater, and how do I know if it's gentle enough for an octopus? I'm planning to get another octopus in the semi-distant future, and to do it right this time. Probably another bimac, but we'll see. Which reminds me, is there a list somewhere on the site of commonly sold ceph species, preferably with descriptions and care information? Thanks in advance, it's great to have found a place with such knowledgeable people.