HELP!!! Yellow spots turning black on leaf edges

Help me please, this is my first serious grow and my first attempt at hydro... I wanted it to be as difficult as possible, lol! But, seriously, I have maybe 6 inch tall plants with a few sets of leaves, no more than a week into veg. I just switched from seedling nutes to veg nutes and am running a 250watt "SuperLocker" with all the bells and whistles...
I noticed the other day there are some yellow spots/blotches on the edges of the leaves proceeding towards the center vein. I fine tuned my PH, and can't tell if I'm noticing "new" spots or ones I didn't see before? However, I did see that some of the yellow-ish spots have turned black, again on the leaf edges and proceeding inward.
What could this be???
What can I do about it???

-Thanks to everyone who replies, I appreciate all the help. I will attempt to post pictures, I'm in no way computer savvy.

"I just switched from seedling nutes....."

no such thing as seedling nutes; seedlings don't need ferts. stop feeding

...........................how old? old enough to flush?

scroglodyte said:

"I just switched from seedling nutes....."

no such thing as seedling nutes; seedlings don't need ferts. stop feeding

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Correction... " Transplant " nutes as directed by TechnaFlora's Recipe for Success... I know peeps who've used TechnaFlora before with good results, any other opinions???

delvite said:

...........................how old? old enough to flush?

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My little ladies are almost a week into veg. So, they're 4-5 weeks. As I mentioned, I'm doing HYDRO. I have been emptying and refilling my resevoir every 5-7 days and topping off with PH'ed water once in-between. It is a combo top-feed/D.W.C hydro system, proven effective... All that being said, do I need to do a traditional "flush"? I have done a flush once or twice, but if I need to I will do it more often.

Id stop using the nutes. Sounds like your frying them

heading2cali said:

My little ladies are almost a week into veg. So, they're 4-5 weeks. As I mentioned, I'm doing HYDRO. I have been emptying and refilling my resevoir every 5-7 days and topping off with PH'ed water once in-between. It is a combo top-feed/D.W.C hydro system, proven effective... All that being said, do I need to do a traditional "flush"? I have done a flush once or twice, but if I need to I will do it more often.

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Exactly what is a flush?? And when and how often do you do it ??