Our Little Science Laboratory

My reef tank got shut down for being too loud, too messy, and too much glare on the TV (the reefer bat signal). After a couple of years off, I have my wife's blessing to try a planted tank IF I keep it neat and quiet. So ...

Our city tap water according to the city consumer confidence report (I haven't gotten test kits in):

• pH 8 (after sitting overnight)
• Hardness 76 mg/L CaCO3 (~4.3 dKH) they gave a range of 11-230 mg/L
• Nitrate 2.1 ppm (0-9.6 range)
• Iron 0-600 ppb
• Chlorine 1.05ppm from sodium hypochlorite, not chloramine

We are on the fence of a 40 Breeder or a 120 (72x24x24) and want a balance of plants and fish that will be relatively easy to keep looking neat. Watching for sales /craigslist for great deals.

Current Dilemmas / Request for Input:

1. CO2 - I need to make water changes as simple and easy as possible. The high pH concerns me and sure seems to call for CO2 as part of a plan to help control pH. I'm a bit nervous about the more frequent trimming of plants. I ran CO2 on my tank 15 years ago.
2. Substrate - I like the look of a sand bottom more than the larger particle gravels, but everyone seems to suggest eco-complete or a similar complete substrate. Sand doesn't work well for topping a layered substrate from what I read. Is there a better solution.
3. Light - I am drawn to dimmable LEDs and the ease of access of pendants like the Keisel A360s. Are there other brands that we should be considering?

Once we figure out the lights, substrate, and CO2 I will start asking for input on where to start with plants.