Problems with growth of microgreens in an indoor growing system

Farm Questions
1

Hi. We have an indoor farm in Delhi, India where we produce microgreens hydroponically. We grow these greens on burlap placed on top of leca balls in 10x20 flats. The irrigation system is flood and drain. We are using LED T5 lights (4 on each level which contains four trays of crops). The lux value is between 4000 and 5000. I have attached some pictures of the farm with this post.
We are facing some problems in the growth of the crops:

  1. Radish: The leaves are not opening up. They remain curled inwards. Also, we have observed yellowing of leaves very early in the crop cycle. Some leaves are also decaying completely.
  2. Red Amaranth: A lot of mould formation is occurring just after germination. and in later stages also.
    For germination, we stack one empty tray over the seeded tray and give it two days.
    We are using tap water whose EC is around 350. Also, we have added a little NPK fertilizer to bump up the EC to around 500. Also, we are sanitizing everything; from burlap to leca balls to the trays we use with H2O2 (50% concentration).
    For ventilation, We have created a frugal version of a fan and pad system. We have 2 exhaust fans which run on a timer. Also, we have installed two pedestal fans which to create some turbulence.
    If you have any idea as to how to fix any of these problems, your input will be highly appreciated.
2

If you are using Burlap then you have to give extra time, and check regularly if your base is moist or not.
Leca Balls will come into play after seeds have developed roots long enough to be in between of those balls.
Do not worry about the yellowing of leaves early in the cycle as they will turn green as soon as you expose them to light.
In case decaying is there, it might be because of the over watering.

For Amaranth , try bottom watering and avoid over watering. In case mold is still there, then dip your seeds in organic anti fungal solution before sowing them.