Excel Dose When There Are Lights On Or Does It Matter?

I was always wondering if Excel, which I think by Seachem's description is CROSSLINKED glutaraldehyde, not glut itself got into the Calvin cycle and that's how it worked. It sounds like Seachem seemed to think so or at least the bit I saw here http://www.plantedtank.net/forums/23-algae/383817-why-does-flourish-excel-kill-algae.html. Hand waving then thinking that the algae, having perhaps a more primitive enzyme to do that conversion is getting this molecule stuck in the cycle, as it were and then turning off the whole process for the algae. If this was true then wouldn't it have to work only when the Calvin light cycle was actively at work?

So the question is: has anyone dosed this with the lights out FOR ALGAE REMOVAL and found that it still works or is this something that to be most effective needs to be run with the lights on? If it needs to be run with the lights on then depending on how long Excel/glut cross-linked polymer lasts before being broken down, it might be best dosed an hour or two after the lights come on and the plants/algae are busy doing their thing. I tried searching here and elsewhere and didn't seem to come up with anything or was asking the wrong search questions. I would be interested if anyone has noticed a difference between dosing in the dark or dosing in the light. thanks