effects of a drop in temps at night

my tent runs about 22-29degree celsius when the lights are on, but when they go off the tent can drop to as low as 8 degrees, is this gonna have a major negative effect on my girls. was gonna get an oil filled radiator for each tent but not got room in them for a couple of weeks until some of the plants go in to flower in the other tent , any advice would be great

hell no this is good it will bring in the nice purple color's oh and the last week of flowering when u flush use ice water it will up the resin and thc levels from shocking the shit out of them ok

That is too drastic of a difference. Most say the temperature swings should be about 15ºf, or about 10ºc from night to day. Your 20º swing is a bit exteme. 8ºC will probably slow growth down considerably, that is downright chilly. It's not going to kill them though.

Low temps are alright.
But if its too much of a number then its bad..
really bad..