So I have had a 100w zoomed powersun running for the past 9 months and I have another that is 150w that has only ran for about a month and a half. I bought them both last year in august. The one I use now is a more white color and the one not used much has a more of an orange color. Is this because of the higher wattage or the use out of the bulb? When do I know when to replace this bulb? After 12 months of use? Thank you!!