How high can I go with the temps in sealed with CO2?

[SamandMax]

I switched to external air without additional CO2. But right after some problem occured.

After removing CO2 and lowering temps (switching to external air) - plants sick?

Because the room was getting way to hot with all the lights on and no aircon, I had to switch to external air. I switched two days after I started flowering cycle. Plants are now 5 days into flowering light cycle. Its ebb and flow, rockwool, SOG. I think the temperature switch was pretty extreme. A difference of about 15 degree celsius and co2 difference of 1000ppm. Pretty much the day after switching to external air some plants are looking really sick and nearly all show more or less sings of …