Yellowing leaves/browning tips!! Help! problems -- 21 days into veg

I'm running 3 1350k lumen 23 watt replacement as well as a 2700k cfl bulb in a grow box, temps been kept between 72-82 for the past 3 weeks (It spent about a week in the 80s while i was getting ventilation figured out). The temperature has been fluctuating a lot and im using FFOF for soil, no nutes added yet. Plants transplanted about 3 days ago. The browning on the tip occurred on only one leaf, which I found kinda strange.
Here are the pictures.

http://i796.photobucket.com/albums/y...ps61266237.jpg
http://i796.photobucket.com/albums/y...pscd3e6aa6.jpg
http://i796.photobucket.com/albums/y...ps80e3d2c2.jpg

Any advice on what's happening to my plants?

Edit: Yellow spots have also started to develop on the leaves of one of my plants. I've been spraying my plants with water to prevent build up of dust and for fear of spider mites. i read somewhere this can cause spots of light intensity? could this also be part of the problem?

Your pic links don't work...

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Originally Posted by OMB

Your pic links don't work...

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<a href=http://s796.photobucket.com/user/poopynoob1234/media/IMG_1491_zps2d2f0d87.jpg.html?sort=3&o=2><img src=http://i796.photobucket.com/albums/y...ps2d2f0d87.jpg/></a>

How often are you watering and what kind of water are you using (tap/filtered)? Also, why do you fear a buildup of dust? You had mentioned that you had gotten the ventilation figured out, so I doubt dust will be forming. I would stop spraying the leaves and make sure there is a fan pushing air gently over the whole plant. This will prevent dust and move clean air over the entire plant, feeding it healthy O2 and any CO2 that is naturally occurring.

I switched my privacy settings off on photobucket so you should be able to see the photos now. And yeah im done spraying now that ventilation is figured out. I bought PH testers a couple days ago and the soil is at 6.5 in the healthy plant and and 7.8 in the unhealthy one. i bought dolomite lime to lower the ph, how often should and how much should i add to the soil? when should i see results?

The other two picture links: http://i796.photobucket.com/albums/y...psdd64e27d.jpg
http://i796.photobucket.com/albums/y...psd600ee9c.jpg

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Originally Posted by My Affair With MaryJ

I switched my privacy settings off on photobucket so you should be able to see the photos now. And yeah im done spraying now that ventilation is figured out. I bought PH testers a couple days ago and the soil is at 6.5 in the healthy plant and and 7.8 in the unhealthy one. i bought dolomite lime to lower the ph, how often should and how much should i add to the soil? when should i see results?

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Dolomite lime is usually added to the medium mixture before you plant. Lime takes a while to break down and it continues to break down slowly. But the thing is, you need to lower your pH, not raise it. You need to add acidic materials to your soil. Dolomite is a buffer that keeps an acidic medium from going too low. Can you get a new soil mixture of the proper pH and transplant?

Yeah I realized that after I added it and the PH jumped to 7.9... I did transplant the plant into a fresh FFOF soil mixture and added a little peat moss to further neutralize the PH. It's slowly climbing down, I'm gonna watch it over the next couple days and see how the PH goes. I may add really diluted vinegar if it gets out of control again as well