URGENT! Plants turning yellow (Aerogarden)

On day 9 or 10 of the grow I added a small nutrient tab, and now a couple days later my plants are very yellow.

Should I raise the lights? Should I empty the water out? I dont understand the whole adjusting the lights with the aerogarden....... with only 3 settings?

Should I just use liquid karma? instead of the nute tabs?

I really need help because I don't want my plants to die

I just changed the water and its at 6.0ph level now.
No nutrients... you think they will be ok?

when should i add nutrients in a aerogarden?

pics would be a huge help......all yellow, new growth yellow, old growth yellow, necrotic yellow spotting?? Be glad to help with more info.

For now you have done the right thing...and yes use proper hydro nutes and bin the aero-tabs.

ok, well the plant is turning yellow in the middle, just on the leafs and its like a circle from the middle of the plant and it fades out twoards the ends of the leafs..

they look pretty good for now tho since i took the nutes out

how about raising the light tho... when do I do that with the aerogarden since its only 3 settings? How do i know when to move it up?