Yellow Edges with Stealth Hydro Nutes

I have some babies that are about a month along and are starting to get a little yellow around the edges.

24 hr light cycle 4x 4' flour. lights

Hydro drip system with rockwool and hydroton rocks

pump runs twice a day for about 15 min

as far as I can tell the rockwool blocks are all staying wet.

I am using Stealth Hydro's "Fire and Forget" nutrients. <http://www.stealthhydroponics.com/product.php?xProd=4>

I have just recently read on their page that having a fan blowing downward on the plants could cause this but here are the pics of my setup






Also any comments to improve system are graciously welcomed (still not too sure about the 24hr cycle)

u can do 24hrs but i dont see a large difference between 24hrs and 18/6. so i would say 18/6 but what is the ph and the ppm/ec

mikmike said:

u can do 24hrs but i dont see a large difference between 24hrs and 18/6. so i would say 18/6 but what is the ph and the ppm/ec

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Honestly I haven't even been checking it because those nutes are supposed to automatically adjust the ph " Furthermore, Stealth Grow, Bloom and Micro automatically pH balance (to approx. 6.5) for 98% of all household water types." thats from their site. I can check it later on. I'm leaning towards switching to another set of nutes any advice on that?

Anyone have any experience with these nutes?? Also should I switch to a different brand that I have to measure so I can constantly increase or decrease nutes?