Yellow Leaves+Brown Spots Lower Leaves

What could it be?

crabs.........

crabs? isn't that something that humans get?

Lets see.. Flush. Lower nute solution. Ph your water. Make sure it is not too hot in your room. Make sure water is not too hot or cold. Give it a week. If that doesn't work stop feeding it for a week a just give it water. If you checked all that put some pics up.. If the brown spots are white actually then you have mites. Go to the Grow FAQ. People ask questions like this all day. It is hard without pics. Good luck..

thanks dude, its been like this for a couple days now i flushed with tap water, and started it on half strength nutrients, i gave my cfls to a friend, and got a T12 2 bulb shop fixture, its got 2 40watt bulbs and a bluer spectrum. It's also a lot cooler with the cfls gone. my plants were off to a bad start anyway there 1 month old and only a couple inches tall but there growing fast.

don't use tap water! use some type of filtered water, either distilled, dionized, or spring water. The pH of tap water is usually too high for marjuana, needs to be 6.0-6.5.

Exactly. You don't know what is in that tap water. Go to the store right now and at least get a bottle of water. This still has some ppm of who knows what but it is better than tap. Invest in a 5 gallon jug for your water and get it from the water machine. Get distilled water. You can also buy distilled water in 2.5 gallon jugs from the store. Clean water is one of the most neccessary ingredients for a legit grow..

Chill guys my plants love my water, i let it stand to get rid of chlorine and add a few drops of ph decrease every time, i'm aware of the tap ph being too high, thanks anyway. i still gotta get me some more fluoros and a ph tester one of these days.

just for the ones who say buy spring water have you ever tested the ph of poland springs?? try it you will be suprised it the last thing i would give my plant without conditioning.

Tap water is fine as long as your ppm is below 300.