7 day old seedlings seem really small??? need nutes? just wait?

Hey guys. Germinated these a week ago today. Came up and sprouted really fast. As soon as I saw the root come out the bottom I put them into my 5 gallon bubble buckets. They just seem like they're growing really slow. I have seen growth it's just been very minimal from what I've seen. Three are critical mass+ from dinafem and the odd one out with the "fatter" first set of leaves is a dinafem white widow.The inside of the leaves looks like it's starting to yellow a bit. Could be a sign of needing mild nutrients? Don't really know as this is my first hydro grow. Maybe it's just me being impatient as well.
Just looking for a little help. Like i said. I have seen some minimal growth and to make sure something was happening I also took the hydroton out slowly and saw new root growth coming out of the super rooter plugs.

More info. Water ph is 5.2. Room temp is 72 consistently. They are under a 1000w hps about 18 inches above. Don't know humidity and the light cycle is 18/6 as of two days ago. First 2 are critical. Last one is the white widow. Thanks so much for any help!

as long as they are healthy dnt worry too much, alot of the time after they establish a good root system they litterally exploade, the 1000w is abit of overkill at the moment but if you arnt worried about electricity bill carry on sir!

edit: up the ph 5.8

Don't think giving nuts will be a good idea. The plant is too small and you might burn it.I have never used the type of soil you are using, but I think it has nuts in it, at least to sustain a small plant. I would think that your small plants don't have enough power to penetrate and form proper roots in that soil... I'm day 9 from seed with my blueberry and I'm in MG ( I know MG soil has a lot of pros and cons, but it's working well for me) I would say to put your plants in a more...softer soil at least until they'll get a bit bigger and stronger. And I would say...of course they need nutrients, but not because your soil doesn't have it, but because the roots are not able to get into that soil and develop. This is my opinion and this is what I would do. But as I said, I don't have experience in your type of soil. Good luck and I hope everything will work well for your plants!

^ what the fuck are you on about?

thanks for the advice. i totally forgot i posted this and forgot to check back in. all three died due to heat stress and no ventilation. giving it another go with one 55w cfl above each plant then switching to the hps after they get a bit bigger. still having slooooow growth. but this time there is one main root hitting water and is growing more everyday. added 1/4 strength lucas formula yesterday as one coty turned yellow and the other is almost there. still don't know why it's growing so slow. but glad to see it's growing at all! haha