Seedling tips yellowing, then browning. Help!

[Sunmaid]

Quick rundown of my setup:

• 51.5"Long x 22.5"Wide x 48.5"Tall "Mother Keeper" Grow Tent
• 4 ft. 4 Lamp High Output T5 Grow Light with 6400k bulbs
• 4 Inch In-Line Fan 165 CFM
• Temps 72-74 degrees F
• Fox Farm Ocean Forrest soil w/ 33% perlite added
• my pH meter is on the fritz, so I can't tell ya how it is ATM.
• Watering when soil is almost completely dry.
• Nutes: None until I started to see this problem starting (again.) Added Sunleaves mexican bat guano 10-1-1 at half strength 3 days ago. Showing no signs of improvement.

This is my second attempt at plants in this soil, which has me wondering about FFOF. These are two different plants, but I have 5 all together showing the same issues. I lost 5 prior to this grow with the same problems, but these ones made it a little farther this time. Any opinions on diagnosis and solutions are much appreciated!

Attachment 284051Attachment 284052

Sunmaid Reviewed by Sunmaid on 04-17-2012. Seedling tips yellowing, then browning. Help! Quick rundown of my setup: 51.5"Long x 22.5"Wide x 48.5"Tall "Mother Keeper" Grow Tent 4 ft. 4 Lamp High Output T5 Grow Light with 6400k bulbs 4 Inch In-Line Fan 165 CFM Temps 72-74 degrees F Fox Farm Ocean Forrest soil w/ 33% perlite added my pH meter is on the fritz, so I can't tell ya how it is ATM. Rating: 5

[Sunmaid]

398 views and no one has a clue.

much worse today. taking my problem to canmag. thanks.