Hydroponics (DWC) Newbie

[atulbaliga]

Hello everybody, I am new to this forum and also new to hydroponics. I am from Singapore and due to limited space here the interest towards indoor gardening.
I have a DWC setup with 6 small pots. Have lettuce and bell pepper in 3 each. It's been 3 weeks now and the seeds took 3-4 days to sprout after which I moved them I to DWC. The seedlings are in a sponge substrate held together in a netted pot by hydroton clay balls.

I record the PH, PPM, temperature everyday twice
On an average PH is 6.5 - 6.6, PPM is 1380 a 1400, temp is 29deg C to 31 deg C

I used my aquarium lights which are 36w x 2 with 7100K each
Also I see the seedlings are green and there is 3rd and 4th leave sprouting.

It's 3rd week and I don't see the roots coming out of the sponge media as I notice in some other threads where roots are flourishing out of the netted pots.