| | Re: Beginner in Maui - Need some suggestions plz!
For the co2 question it's really up to you and what you plan on doing with the tank. I'll try to share with you things that I think you should know and consider.
In my experience, all things being equal co2 will pretty much make everything grow better. There are also some plants that simply won't do well w/o the addition of co2. The use of co2 will open up doors as far as the plants that you'll be able to grow and will also help most plants grow faster. However, if you are willing to choose from a smaller selection there are many plants that can be grown w/o co2 and low to moderate lighting.
Currently all of my tanks are either breeding tanks or grow out tanks for fry. They're all barebottomed tanks with sponge filters and none of them have co2. All of them have plants though. I just choose things that I know will do well in those conditions. Typically that ends up being plants that like to grow on driftwood or rocks......ferns like Bolbitis and the various cultivars/clones/species of Microsorum, as well as different species of Anubias and moss. I also have a few potted plants here and there, mostly various Cryptocoryne species. There are a lot less plants to choose from but I actually really like all the plants I'm keeping and would still keep them if I were using co2.
So to answer your question I think it comes down to deciding if faster growth and a bigger selection of plants you can grow is worth the extra costs of co2. Keep in mind that if you do choose to purchase co2 you might also want to upgrade your lighting to make full use of all that co2 your aquarium will suddently have. You'll also probably want to fertilize more which is also an additional cost albeit a small one.
As far as DIY co2 that's also really up to you. I've tried it and found it to work relatively well. There was enough of a difference in growth that it prompted me to purchase a pressurized system. This was back in 2000ish and I no longer have the system but I just purchased a regulator and will be setting one up again. My suggestion is if you enjoy DIY stuff like that then definitely give it a try. After a month or so I got tired of maintaining it so I bought the pressurized system.
As far as the fish that's totally up to you. Here's some things to consider. Sometimes small fish are good for planted tanks because they don't bolt around the tank uprooting plants and knocking things over. You also might not want fish that tend to dig a lot. Personally I like to keep only a few fish in my planted tanks. I feel like this along with frequent water changes really helps to keep algae down and grow nice plants. The tank I grew the cleanest plants in was a 40 breeder that only had 3 Otocinclus and 1 flying fox but that's probably boring for most people. My advice would be to go with less fish if you can. As far as species go, are there any fish that you really like?