I have not used any chems ever in my octo tank, and would not recommend it. I have not even used de-clorinator or the like. Just good distilled water and salt. (you can use RO/DI aswell) :D
BTW -What other marine experience do you have?
I haven't had a marine tank for years. I've raised tropical fish and had a brackish tank recently, but my tropical fish I moved outside and now I want to set up a marine tank. My friend has had his tank for years and swears on these additives from past experiences.
I know most chemicals are bad, but these are mostly bacteria from what I understand. I have plent of RO water and my friend said he could supply me with water from his tank (it's never been treated with any copper or other medicine) to help get things stabilized faster.
I am not going to lie there are many ways to speed up the cycling process of a tank. It is just simply that the recommendation of three months is to get you into the "habit" of caring for marine life again (or teach you in some instances).
You seem really eager , and I do not blame you there (I was too) :D , but lets get the basics going. Is your tank curently set up, or are you planning on just setting it up and then adding all the stuff we talked about and an octo a few days later?
Again, I don't blame you for being so eager (as you obviously seem to manage a few tanks), but octos are a different responsibility. In other words, more things that are fatal to an octo than other marine life. I.E. Nitrate, Ammo, any number of certain spikes could lead to problems. A cycled tank is not immune.
Please do not view this as negative, I just really care about the animals we house and the people that do so!!!!!!