10 days old seedling SICK!!! Please HELPPPPPP!!!!!

this is my very first grow and things started off just fine, but then my little girl (nirvana white widow) start to get sick,here's my set up:
75W CFL;top feed hydro;started in rock wool cube;distilled water with quarter-strength Lucas formula;ph 5.2-5.8;ppm180-200;temp:77F-80F.I'm really worried now,any help will be appreciated. and here's the pics.,she starts to have purpleish hue on the leaves and keeps getting worse, I though it could be lacking phosphors but after changing the nutrient things are not getting any better.

idk, could be a number of things......but 5.2 on the pH is way low, imho...I thinkn you start getting lockouts at 5.6. You want 5.8....a drift to 5.9 is okay maybe. Why the distilled water? The color definitely means something.....and your ppm's are way low, again, imo. Is the little rw cube staying too wet--soggy? You'll get help, don't stress too much over it peace, gman

There could be different reasons why your plant is acting that way. If it was me, I (wouldn't) use any nutes at this time and just plain water @ 6.8ph. You could also have some sort of issue with the cube you planted it in, maybe from it gathering some sort bacteria. Flush it with plain water and just use proper ph balanced water for a bit and it should recover.

Did you wash all your equipment before using it or did you just throw it all together and get the grow started?

thanks for the info, It might be the cube so im just gonna flush the whole system with plain water for a bit and see how it goes, ill keep posting

Is the lucas formula a complete feed? You might be better off with 1/8 strength at that age...
I don't really feed them until the bottom leaves start to turn yellow.

Your plants are experiencing nutrient burn. Quarter strength Lucas formula is too strong at this stage. I'd suggest 1/8 maybe even 1/16 strength for the first week or two... Hope this helps! Also, try to get your ph level around 5.5 to 5.8. Your plants will do better in that range.