co2 tank size 5lb or 20lb

[reefnut1]

I am trying to decide what size tank that I should purchase for my reef system. I currently dose with 2 part but I am planning to go with a reactor in the next few weeks.

I have no idea how much co2 my system would use yearly. I would appreciate any thoughts on how many lbs per year that you think my system will take. I know it will only be a guess but I have no idea at this point.

My system is about 330 gallons. With a lot of SPS and LPS corals.

Should I buy the 5lb or the 20 LB tank? I am not asking because of the cost of the purchase but to give me an idea how often I would have to fill one or the other size.

 

[Vegas RN]

From what I was told the bigger the better but you should always have one on hold for the switch out.