bro.. 4x2x2 use CL450 for short term is good.. but long term not good..i use CL450 for my tank , which spec is same as u but the result after 1 yr it gone worst.. yaya.. hope u might wan to reconsider it again.. sell it and change to CL650.. as it only cost u abit more.. plus the electric it consume is more and it will make u faint when u see ur electricity bill.. haha.. that wad i have gone through.. and it my 2 cents..