Diagnosis help?

[hydroninja]

Hi all, I'm a first-time grower, I've been growing for just about 2 months. I have some Hunan chili peppers I bought from Amazon currently well underway, about 2 months old, and my leaves are showing some disturbing signs right as the peppers are really starting to grow big.
 
I thought this might be a potassium deficiency, but my local hydroponics shop said it's more likely magnesium. I've only had maybe a dozen leaves across all the plants turning yellow, but it's just started happening in the last week and I'm worried.
 
I'm using Dyna-gro Bloom, Mag-pro, and Pro-tekt at the recommended solutions, but the leaves aren't getting less yellow, they're slowly getting a bit more yellow. They have some faint yellow spots in most of the leaves when viewed in front of the light, but only recently some of them have progressed to being totally yellow or a few wilting and dropping off.
 
Could it also be under-watering? I have the timer set to fill the basin every 6 hours for 2 minutes, so 4 times per day for 2 minutes each time.

 

[Oleic]

What grow medium are you using (e.g., perlite, rockwool, etc.)?  
 
I think peppers do best with Kratky, DWC, or Dutch Bucket hydro techniques.  With Kratky and DWC, the roots are constantly submerged.  With Dutch bucket, the roots are drip irrigated regularly (I drip constant, others stop the drip at night - depends on media and temperatures, etc.).
 
8 minutes sounds like way too little.  Especially as they are getting bigger. 

 

[hydroninja]

Thanks, I was beginning to suspect maybe they're not getting enough water. I had them on a 30 minute 6 time per day cycle, but they started to develop signs of edema, so I cut it way back after reading some other hydroponic pepper websites talking about 4 times for 1-2 minutes per day. I'll increase it to 5 minutes per session and see if they are happier.
 
I'm using hydroton for the medium. I'm basically following fatalii.net's hydroponic guide for chilis.

 

[Oleic]

I start all mine (50 this year) in Kraty containers with half-strength nutes.  I use Maxigro for the first couple months (then Masterblend, Cal Nitrate, and Epsom salts) which works great.  It comes dry with  scoop, and you use a teaspoon per gallon for the first month or so (I actually start a quarter strength till they have a few sets of true leaves).  
 
Overfeeding can cause "nute burn" (do an image search), and I've found that using a little less nutes doesn't seem to bother peppers.   
 
You method is similar to Dutch buckets.  Perlite holds more moisture than Hydroton, so yes, I think increasing the watering would be a good idea.  But I'd also take it easy on the nutes at the same time.  The leaves are more likely to droop if under watered, and yours don't look so bad in that regard, so consider that this could be nutrient burn.
 
Good luck!

 

[samdizshiz]

I second that you might be over feeding

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[hydroninja]

Thanks guys, I'll redo my whole nutrient solution this weekend and see if that helps. I admit I may have freaked out a bit when I saw some of the yellowish spots, thinking it was potassium deficiency, and over stacked the nutes.