Newbie third grow - Temperature Issues

Hey guys, on my third grow, still a total newb tho. Started having heat issues on my last grow. Was averaging 95° while lights on and 65-70° when lights off. I assumed the issue would go away as summer passed. However I'm a week into my third grow and am still getting up to 95-96° with lights on. The ambient temp of the basement is kept around 60° so the dark temp won't change much. I have tried increasing the fan speed on my exhaust and added a second small circular fan, so 1 circular facing plant (downward) one facing upwards passed plant and towards the lamp. I also changed the light schedule so the light would be on during the coolest period of the day (11pm-5pm). But after a week still no change. Also now my humidity is down to 16%. Is there something else I can do to lower and stabilize the temps? I'm guessing 30° shift between light and dark is just going to stress the plants.

Setup info:

Tent grow, 3'×3'×6', 600 watt hps lamp, small exhaust fan in tent(top) exhausting air out @ High-low to med speed and 3 small circular fans (desk size) to circulate air.

How many CFM is your exhaust fan?

I think you need a bigger exhaust fan to pull the heat out more efficiently.
All the other fans are just blowing hot air around, not really helping.

As far as the temp swing stressing the plants, as long as the swing is consistent they'll adapt. How did your last grow do?

I'm not sure the CFM right now, not at location and don't know off top of head.

You are probably right tho, probably need a bigger fan, was also considering a hood exhaust. My last grow was ok, not great but produced. Haven't weighed yet but looks about 4-5oz off one plant. The first grow temps were lower and more stable, averaging 70-85° with about 50-60% humidity. Not sure why it's changed now.