harvest weight slipping

So my growing is done in my basement of a very old house. I am growing sog style. Have been doing it all through last summer and this winter. As winter has rolled upon us my harvest have fallen dramatically. I have upded my lights in a 5'x4' room from one 400hps to two expecting dramatic increases. But yet the weight just keeps falling. From as high as 180g from 12 plants to under a 100. I think my problem is temps. It has been single digits for quit some time here and my temps are as low as 52 with the lights off and as high as 84 with them on. This is nearly 30 degrees differance at times. This has to be the reason. I have just a few days ago came up with having a heater on a separate timer to be on only when the lights are off and kept the temps within ten degrees from day and night. Could this temp drop alone be the one solution to my problem. I think so just hoping for some feedback


Lg

yes m8 my temps where as low as yours and the plant didnt seem to flower right ive added a oil filled radiator and i think ive sorted my temps out and they are growing a lot better anyone else think its temps

Indeed the low temps are most likely the cause of your drop.

And you have new bulbs right? Not the same ones you've used all along...