29 Gallon Lighting

Increase in light increase the plants DEMAND for CO2. The more light they have, the more they want to grow and the more CO2 they use. When they have high light and the CO2 gets all used up and runs out, there's where your algae problems come from.

Adding light will not slow the CO2 produced in my tank.
- Not sure what you mean. It will increase the CO2 consumption in your tank..

Adding light will increase the growth of my plants.
- True, assuming they have all the ferts (including CO2) that they need. If something is missing, it will limit growth.

Adding light and CO2 will increase the growth of my plants more than just light.
- True, in a sense. The more light you have, the more CO2 your plants need to maintain their rate of growth. High light without CO2 can be a recipe for algae mess.

Light is like pressing down the gas peddle, makes the car go faster, makes the plants grow faster. BUT if you don't have CO2, I guess the car analogy would be "enough oil", then you'll burn up (or get algae). It is also easier to swerve out of control with high light (high speeds), but the CO2 goes a long way in helping with that - much like changing your oil and getting new brake pads.

... ok, maybe I don't know enough about cars to really make that work... but perhaps you get the idea?

There is always CO2 present in your water, even if you don't inject any. It is present in your tap water, lake water, etc. Algae does need CO2 to photosynthesize, since it's a plant just like the plants we try to keep. The reason that we inject so much extra CO2 into our tanks is that algae can more easily utilize the low ambient levels of carbon in the water than can the more complex plants. So, if we raise the levels up to what the more complex plants like, they can out compete the algae for nutrient uptake and carbon too I suppose, stamping out algal growth.

A 2x65/55 watt fixture is borderline too much light to run full time if you're just starting out. I have the same size tank as you, and I bought the orbit fixture with lunar lights, and those lunar lights are really dim and I think kinda suck btw. The fixture is nice however, and if you can find a good deal on them, I'd say go for it. You can independently turn on each light, so while you're getting things figured out and stabilized, you can just run one light, then later on you can increase to two lights. I'm running both lights on my fixture now for eight hours a day. I use DIY CO2 that is run into the spray bar of my canister filter. I've been toying with this much light for a while, and until I got my diffusion up to par, the tank was often growing undesired amounts of algae.

p.s. nice analogy Jen