Looking to go with a 3 x 150 watt HQI /T5 combo fixture for my 72 x 18 upgrade. Now I know whats quiet to one person might be loud to someone else but I'm interested to know if there are any fixtures out there that are pretty much silent. I'm pretty sensitive to noise, especially when it comes to either ballasts that buzz or fans that are too loud. Any recommendations as far as 72" fixture? Thanks.