Thanks for that Dave, after reading the above I am definatly getting an arcadia

Thank you for all of the replies:). Is the Arcadia bulb actually a combined bulb? I have just received my 100w Powersun bulb today from surrey pet supplies so i'll make sure hwen it runs out i'll get one of the Arcadia ones if it is a combined one. I also bought a zoo med dimmable clamp lamp then when i opened it i realised i can not use it with the bulb i have bought so i'll have to see if i can take it back and get a different one, hopefully i can.