HELP! my plants dying!

[tgrower]

Hi, I'm new to the forum so I have yet to introduce myself (I will but this is urgent!)

I am a first time grower and have had my plants going for about 3 weeks.
They are deep purple Kush and blueberry Whitewidow...grown in some top soil I found in my garage.

All the plants were doing fine and last night I watered them with a nutrient solution.(I water with nutrients then regular water, then nutrients again, then water..and so on and so forth)
I use DNF(dutch nutrient formula) that I got at my local growing store.
It is a 2 part system and the guy at the store recommended I start with 2ml of each in 1 liter of water.

Last night I increased the dosage slightly to 4 ml of each in 1.5 liters of water.

This morning when I checked them all the plants seem fine..some seem a little better, but one has taken a dive off the deep end. The leaves are changing colour to a slightly yellowing tinge and they are sort of rolling up.
It does not look healthy at all.

I do not think it could be too much chemicals because I have been alternating watering with regular water, and I did not increase the dosage by much.
However I am no expert so let me know what you guys think.

P.S...I have not been testing the soil pH...so this may be the case. Just been too busy to go out and buy a test kit. Let me know if this could be the problem and ill get one right away.

Thanks a lot for your help!

[randumbdude]

You most certainly should be testing the run off water! If you're gonna be adding nutes, you need that tester. Like now.