i just got back from vacation and discovered this... comments/opinions please!

aight guys and gals, i just got back from skiing for 4 days to discover that the temperature in my grow room ranged from (yikes) 48 degrees to a whopping 87 degrees (my thermometer keeps record of the highest and lowest temp). tho the plants dont look as bad as i would have expected for this terribly wide temperature variation, what i did immediately notice was the the leaves directly under the light are quite yellow (but the leaves not directly under the light are still a rather healthy-ish green colour) but there are about a dozen sets of leaves that have started exhibiting rather equally-distributed brownish spots (based on other ppl's posts i've seen its reminiscent of nutrient deficiency). also, the humidity was a lip-chapping 25%. normally, my temps range btwn 66 and 82, with humidity ranging from 40-60%. i immediately changed out their nute soup with a fresh batch (the old batch was about a week old), raised the temp to 76 degrees, refilled my humidifier with water and started it back up. what i'm wondering, from some of ya'll experienced folks, is whether you think this unfortunate turn of events is going to cause a serious setback in bud production. today marks the beginning of the 3rd week of flowering, so they've got a while to go, and overall i wouldn't say they look 'unhealthy' (neglected for a few days - definitely) but i'm just wondering if this kind of neglect (im slapping myself across the face right now) is likely to cause such a detrimental impact on bud production to just kill the whole project and start over? in other words, if the temps always stayed btwn, say 73 and 80 degrees, and humidity was a constant 40-60%, do u think i would likely end up with twice as much bud as im going to now? they are white widow. also i will throw up some pix this afternoon/evening, i just dont have my digicam with me at the moment. any kind of feedback from first-hand experience would be appreciated. also, one last thought is i was wondering if the brown spots, which i do believe to be nute deficiency, could be caused by the water in my bubbleponics system getting so cold (48 degrees). does low temp like that cause the roots to not be able to absorb nutes? thx for feedback, and any advice is appreciated (tho i am going to wally-world today to buy a thermostat-controlled space heater to ensure the temp never drops below 70ish ever again). thx guys!

Tip # 1 - How to identify a Phosphorus deficiency
If your crop is deficient in phosphorus, the growth will appear stunted and often dark green in color. Also anthocyanin pigments may become noticeable. These are generally red or blue.particles. (Some growers like these pigment colorings. So if you want to encourage this coloring, keep your floor cold in the evenings.) If you want to avoid the problem, elevate your pots off the floor using a plastic mesh. This will assure drainage while providing a layer of air between the concrete and the pot. Remember, when a root mass temperature goes below 55f, the plant will be unable to absorb a proper amount of phosphorus. To correct the deficiency problem, look for a hydroponics supplement that provides an ample amount of phosphorus. Add this to both your nutrient solution and use it as a foliar spray. Follow the instructions on the label.