Help! First Hydro grow (DWC)

I just started my grow room my babies have been growing for 12 days now 2 bag seed and 3 Chrystal strain that have been growing about a week now. I did a res water change yesterday using tap water, im using a 10gal res (cleaned out in bleach hot water not sure if i should have) added my nutes about 7.5 ml of each 3 part MICRO, GRO, and BLOOM im using Gen Hydro nutes. PH is around 6.3, PPM is at 135, Temp in my room is about 75 during the day and about 63 at night, Lights on 24/7 now thinking about switching to 18/6.

This morning i woke up to check up on them the 2 bag seed plants look a lil yellowish to me so i took a look at the roots and it looks like they have a slight brown tint to them should i be worried? how can i fix this problem? Ive posted some pics any help would be much appreciated Thanx in advance.

looks like a classic case of root rot.... bet its because light is getting in your res through the net pots.

I have the same set up and i ended up buying some net pot covers it helps alot with alge growth as well. also make sure light cant get throu your containers.

Thanx yea I was wondering why when I did my res change there was a Lil alge in there. It's clean water now so while it's clean I'm going to seal up around each net pot thanx I would have never guessed that it was light getting in the res that was browning the roots. Is my ppm too low? Do my plants look small for two weeks? The 2 smaller ones are the Chrystal strain and they're only a week one