1) Money is not an option. Which of these three would you recommend? Im thinking the black and green contrast will look good.
I agree. I like black substrate. ADA Aquasoil Amazonia is black. Everyone who uses it sings its praises. It's gotta be good stuff. Personally, I'm a big fan of sand. Just sand.
1a) Should I use all of one of the types of mix in sand with it? There has been some research done that supports that idea. I don't know where I read it ( I think it was Tom Barr??) . Can't hurt.
2) Does any of these have to end up being replaces?? I read on a few other sites that the eco for instance only lasts about 7 months and then you have to completely change it out again?
I don't know for sure. I'd imagine after the nutrients that it contains are used up, it's just another inert substrate like sand or gravel. Once your tank matures, the mulm will act as a sort of fertilizer.
3) Would you still do like a montly vacuuming, or need to use plant food pellets etc?
I don't vacuum the substrate. I fan over the substrate to remove the fish crap. I don't stir up the substrate. Some will say doing so will create anaerobic pockets that, if stirred up, will cause fish death, etc. I've not experienced this myself nor have I studied it.
4) If I overhaul all my gravel, I think I could keep the same water in there and carefully remove the gravel so as to not loose too much of the good bacteria.
Nah. Most of your beneficial bacteria resides on your gravel and in your filter media. If the gravel goes, so goes your bacteria. No biggy, it'll grow back. May want to reduce fish load if possible for a few weeks to reduce chances of an ammonia spike. Or you can stick in a bunch of fast growers for a few weeks.
5) Finally the whole peat thing. With whatever of the three types you might recommend, Ive read some posts that said to put down a thin layer of peat and then the substrate and others that said not to?
6) Is CO2 really necessary? No. It is a good thing to look into though. A tank with supplemental CO2 will provide faster growth and create more interest ( IMO) . Your water has CO2 dissolved in it out of the tap. If you aren't pumping a bunch of light into the tank (maybe 2 wpg or less) you don't have to add more. Plants need a few things to photosynthesize. Light and CO2 are big ones. The more of those you provide (within reason and with balance) the more they will grow.
7.)I mean how do you know when you need that if you have the right substrate and lighting?
To me, the right substrate is the one that holds the plants down and gives them something to root in. Other than that, your light, CO2, and ferts are right if you've got healthy plants and little algae. No test kits or computers, the plants will tell the tale.
Sorry so long.
I hope someone can help.
Hope i did