Im thinking about starting a nano reef but i dont know where to start. I dont want any fish in it or do i need to have fish? No, you do not have to have fish. Would a 10 gallon tank be ok to use? Yes, keep in mind that the smaller the tank the less stable it is. What kind of filter and lighting do i need? You can do anything from a complicated under tank sump or as simple as a HOB power filter. Lighting depends on what you are wanting to keep. You can use PC, T5, or even MH lighting. Do i need a heater in it? Yes, unless you are doing a cold water tank then you need a chiller. Are they high maintenance? Slightly more than an equivalent sized freshwater tank. Are they expensive? They are not cheap. Again, costs will depend on what you plan to keep in the tank.Do you have to let it run for a couple days or can you put stuff in it right away? Generally you have to let the tank cycle which can take as little as a week or as long as two months or even more. What all do i need to keep it up and running? Once the tank is up and going then you will need water, salt mix, food for fish/inverts/corals, testing supplies, and stuff for general maintenance. There is a lot more as well, this is just the very very basics. Lol i think thats all the questions i have! If i left anything out like something i need plz tell me. Yeah, you need to do lots and lots of reading and research. Keeping a SW tank is not hard but it is far from being straight forward. If you do not do things correctly and just jump in without doing your homework you stand to loose a lot of money.