Hmmm, the only thing I can suggest is getting a table top lamp dimmer and adjusting it down to as close as the Exact temperature needed. When I plugged them in for my 4 Tanks about two years ago I have not replaced any bulbs yet! And mine run 24/7.
In the summer, I use 100 watt bulbs and have them st 40-60%. In the winter I do the same with a 150 watt.
So, my summer bulbs are running about 8-9 months and have gone 2 cycles without burning out! Same for the winter bulbs as well, except for 3-4 months per cycle. :)
Before I got my dimmers I kept 2-4 of each wattage of white and red bulbs on hand due to frequent burn outs. I experimented with the black/blue bulbs, but settled on red for 24/7.
Hope this helps
http://uploads.tapatalk-cdn.com/2016...b265eff276.jpg
Available at Amazon and Loews for under ten bucks