T5 light question?

Hi there thank you for reading my post very much appreciated.

Ill get to it. I'am curently in the early 2nd week of veg. My question is when my hps shuts down for the 6 hours, can i still keep my 2ft t5 light on or will this cause stress due to lack of darkness.

Would this cause faster growth to leave the t5 light on. Or would this just be a waste of energey.

Thanks again for reading and all the help this wonderfull site has given me.

um , it might cause stretching, cos of the lack of light.
but mj can only process 18 hours of light a day, so id leave it with just 18/6 personally.
good luck.