You'll need to post your picture on some website that doesn't require membership to view it.
flickr is what I use, but I know there are a bagillion.

I didn't expect the hotlink to work...

http://www.flickr.com/photos/40495041@N03/3724750193/

After a bit of research i think i found my problem. I am using Ammonium sulfate in my mix. Apparantly because ammonium is absorbed so rapidly by plants, its creates a toxic situation. :(

Always these chili pepper problems... it's because it is commonly said and accepted that tomatoes and chili peppers (not to be confused with bell peppers) have similar nutritional needs, which is completely false.

Looks like N-overdose (burning) indeed...
While tomato plants can cope with higher doses of Nitrogen, Chili peppers need much less and get intoxicated much earlier. Not sure about the quicker uptake of ammonium sulfate (compared to calcium nitrate), though!

The reason why amonium sulfate is used, is probably the fact that calcium nitrate can't be used in monomixes. Also with ammonium sulfate you may have a lack of calzium (compared to calzium nitrate which has high -, it doesn't have any calcium content at all), in case your tap water has rather low calcium content. The next issue would be that less Magnesium sulfate is used in this combination, because ammonium sulfate provides much Sulfur as well. A lack of Mg in such Mix is another obvious consequence.

Doesn't look that way to me at all. Looks like a lockout. Not sure how you get 'to much N' from the flickr pic

For fear of being accused of mobbing, it doesn't look like too much nitrogen to me either. Nitrogen burn is also called tip burn because it usually starts on the tips and progresses along the edges first. Tip burn is really just a symptom that is associated with many things, but Nitrogen toxicity is one of those.

I think it looks like lockout, too.

could it be spider mites?

Drop waaaaaaayyyyyyyy back on nutrients and make sure your Ph is about 6.5.

Of course, extremely high nutrient concentration (resulting in a N-overdose and leaf burning), as I said earlier. Btw: the PH should be between 5.8 -6.2 for peppers, or around 6 if you prefer. PH-6.5 is already too high.

I've been growing chiles in hydro for a long time and test nutrient Ph and ppm daily and the best results are very near Ph 6.5. I have years of data.

They will grow at other than 6.5, but grow best at 6.5

Good for you and your data willard, I stick with my 5.8-6.2 and exchange data with major growers in S.E.A.

What is true in Paris, may be false in Rome... as we know ;-)