What's causing this dbl temp peak on Apex

[kevin_e]

My best guess is that the first peak is from the t5s that turn on at 12 noon, followed by two more at 1 pm followed by the halide at 2 pm. Obviously there a bit if a lag. But why do I only get the dbl peak occasionally?

http://uploads.tapatalk-cdn.com/20160912/af5f77786b5a989229684b3d838d61d8.jpg

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[kevin_e]

See below

[kevin_e]

Also, why does the slope of the first peak begin to rise before my t5s turn on and peak as the turn on? If it were daylight, you would think I would have a triple peak, or a steady rise to the main peak, instead of it leveling off when the t5s turn on.

[bertoni]

The peak might start to rise with daylight, as you suggest, but it might not reach steady state before the T5s start running. That second peak is fairly small. I'm not sure I can guess why it's there. A bit of hysteresis in the temperature controller might do that. The levels all are safe enough, so I wouldn't worry much.