If I setup a tank with just lr/ls in it, no fish/inverts/corals, does there need to be filtration? I would have a couple of powerheads in there to move the water, but does it need some kind of carbon filtration or something?
With an adequate amount of live rock and flow through it, other means of filtration is not necessary.......live sand included.
Carbon is used to "polish" the water and although NOT necessary, it can be very beneficial at times to remove odor, color, and organic pollutants. Personally i run carbon about one week out of the month. Carbon also cleans the water column of some trace elements that you dont want to be rid of.
Well its just that its an eclipse tank and I dont like the filter system on it. It makes salt run down the back of the tank because of the wheel thing and it makes too much noise. But if i threw 2 165gph powerheads in a 29 gallon tank, wouold that be sufficient with a 2" bed of live sand and a few pounds of rock?
If you are just going to put rock in there for a few months......and then set it up as a reef tank...you should take that opportunity to cook your rock instead. DONT put sand in it........cover it up with something so light doesnt get in and every week or two pull the rock out and swish in buckets of saltwater and do a 100% waterchange...it will allow the phosphates to be turgored out by the beneficial bacteria, you will be rinsing the phosphates out when you rinse and swish it every couple of weeks. You will be amazed at the amount of crap that will come out of your rock for the first couple of months depending on how often you rinse and swish. All algae will die in the process....including the coralline..but it will grow back.
oh...you didnt say that it was in planning for a 300........if you want to set up your 300 right try to buy the rock now and do the process i explained in a 75 gallon+ garbage can in the garage.....you wouldnt regret it.