1. my live rock has been sitting in the garage for about 4 months, would it recolonize itself if i were to clean it up and put it back into my 46 gal
Assuming the rock dried out...the short answer is yes, eventually with some limitations, it would recolonize with Bacteria needed for the nitrogen cycle. Without live sand or live rock this would be a slow and painful process that most lack the patience for. There would be no 'Pods or other critters and no coralline algae spores present to recolonize the rock otherwise.
Look at it from this stand point...If you wanted a garden you wouldnt just till the earth and then expect a bountiful harvest come fall without planting some seeds...right? Think of a new tank sart up the same way.
2. would i have to get new live rock to populate it?
This would be most highly recommended to recolonize with Bacteria, Pods and other critters not to mention Coralline Algae. It would give you much faster results and far more diversity.
3. i was thinking about putting it in a tub and running salt water in it with a powerhead for about 3 days then a final rinse and put it into the main tank to start the cycle.
If its been dried out and setting in the garage then Id say good idea on the thorough soak for a few days and rinsing. But with nothing batcteria wise to innoculate the tank your not going to have much of a cycle and it will be a long drawn out affair before there is enough bacteria in the tank to handle live stock in my opinion. Again I would suggest buying a couple pounds of live rock to help you out here.
4. after that, i was thinking about buying pods in a bottle to help jump start the pod population and to help colonize the rocks.
If they are alive when you get them this indeed will give you a colony of Pods from which to go forth and multiply. The water the Pods are in will provide some bacteria for the tank too. Buying a few pounds of live rock will do the same thing.
You have the 20 gallon started up still right? If so have you considered breaking it down and dumping it in the 46? The water has Bacteria and spores and Larva in it, the Live Rock is alive and has lots of critters if its a healthy tank and been running a while...
5. i've used argonite substrate in both my previous setups but i don't like it.
The first question I have to ask is why not? What was it about substrate that you did not like? Is it strictly a cosmetic thing or a maintenance thing than makes you not want to use substrate again? There aint nothing wrong perse with niot using substrate I am just kinda curious as to why, thats all.
6. i will probably just use a undergravel filter plate at the bottom to put my rocks on.
What gives with this idea? Again nothing wrong with it. Yes it will work, yes it will support the weight or at least should without a problem but wouldnt this defeat the purpose of going bare bottom? I mean this or egg crate is sure to collect and build up cude and stuff causing problems a couple of months down the road or require that you blow everything down with a power head on a very regular basis. This is maintenance intensive and I would much rather spend my time looking at my tanks not working on them. But it is your tank and if your okay with this then go for it. Im just not sure I understand where your comming from with this idea.
If your concerned about the glass bottom and the rocks causing pressure spots and possibly cracking the glass then Im following you on that. But as long as the rock is stacked wisely and wont shift suddenly or avalanche on you then you shouldnt have a problem with the rock being in direct contact with the glass bottom of the tank.
7. is there any major disadvantages of running barebottom if i keep up with regular maintenance?
If pristine water quality is your over riding goal then a BB is hard to beat!!! Cleaning a BB is a breeze, just siphon the crude off the bottom where if collects and retop off with some new water. Only problem with that is if you think cleanlines is next to Godliness then you will find your self doing this every 2-3 days or have it irritating you to death until you do.
With substrate in the tank, it will slowly disolve releasing minerals and calcium into the water. This allows for excellent buffering capabilities allowing for good stable Ph, Alk and adds trace elements to the tanks water. Your live rock will do the same but at a much slower rate. Depending on your live stockyou may find yourself having to supplement the tank more so than you would if you had fine sand substrate in the tank. Again this depends upon the specific set up and has a lot of varibles involved. So while BB tank will lessen the chance of a nitrite, nitrate issue to an extend you might discover that you now have to work at maintaining Ph and Alk a lot more than you did in the previous two tanks you had. If your okay with that possibility then go full speed ahead with a BB tank.
The other aspect with substrate in tanks is the fact that the sand provides a horrendous surface area for colonizing bacteria, far more than you could ever hope for with a BB tank. Most Berlin Style tanks are set up with BB. If you look at these tanks, they have a few things in common. They are very lightly stocked, have very brisk water movement, hooked up to sumps, use large effcient skimmers and are often heavily dosed with supplements, mainly calcium. Every Rose has its thorns...and almost all reef tanks are a comprimise to one degree or another. All the differnet styles of set ups (and thier hybrids) will get you from point A to point B but they just have a little different way of doing it.
Then there is the aspect of asthetics...Personally I have seen some nice BB tanks...a year or so later after coralline algae has covered up all the glass. In the mean time I cant stand the sterile look of glass bottoms, but thats a personal hang up I have. This may not bother you. Again its your tank and if this is what pleases your eye then thats what counts the most!
Just my thoughts and opinions for what they may or may not be worth.
