Do I Need Co2?

[AngelsFTW]

Hi guys

I've had a planted tank for a while now but I just got a new light which gives me around 3.1 WPG in my 55g. I've been using flourish excel daily but I'm wondering if this is sufficient for my lighting.

The main plants I have are Amazon Sword, Vals, Red Tiger Lotus, Java Moss, Java Fern.

I spent a lot of money for my lights and I don't want to spend more on a CO2 system. Do you guys think dosing flourish excel and other ferts will be enough or do I need pressurized CO2?

 

[ech0o]

Angels there is no real way of telling except by trial.  You will notice different kinds of algae with the different level of co2 in the water, and it seems to change from tank to tank.  Also fertilizers are another number in the equation once dealing with high amounts of light, and co2.   I would keep tinkering until it seems the algae growth isn't terrible and your plants are pearling and growing nicely.

 

[three-fingers]

As ech0o says, there is no definitive answer we can give you, every tank is different and depending on too many factors to count (flow in the tank, brightness of room, nutrients in substrate, tap water stats and so on...), your plants may be deficient in carbon down the road, or they may not.
 
3.1WPG sounds like a lot of light though tbh, and will make your plants grow fast and therefor require more nutrients (including CO2). What kind of lights are they and what are the dimensions of the tank?
 
I know you've said you've spent a lot on lighting, but if you don't want to invest in a CO2 system or put up with a lot of algae, I have a feeling you will have to reduce your lighting!
 
Another important thing to consider is flow rate, the higher the flow rate the better distributed your nutrients will be to your plants, and this includes the CO2 that is naturally in your tank. 
 
So basically, before you decide if you need extra CO2 or not, there are other steps you could take to both reduce the plants demands for nutrients and make sure they are as readily available to them as possible.
 
Other information that could help us advise would be what type of fertiliser you are using, how often you are using it, and how many fish are in the tank too.
 
Like I say though, every tank is different, we can just give you some guidelines based on experience .