Home for 2 mothers. question inside!

Alright so as the title says I am trying to make a home for 2 mother plants. Basically I have made it and just curious if anyone has any experience using a really shallow 6" deep water garden.

Below are some pictures, I am growing with hydroponics already in my grow area but I need a second area to keep my unknown clone female and hopefully a strong white widow female alive and vegging.

I am going to place 4 air stones in the unit, I already use proper water (R/O) with 25% nutrients. The lights are going to be taken from my current canopy tomorrow when I receive my MH/HPS setup for the flower / veg area. Lights for the mothers will be 9 x 2' HO T5 fluorescents.

So everything is good in my opinion except for what are some thoughts about such a shallow water garden? I have read that as long as I keep it really well aerated I should be good and not have root rot but I am curious if anyone has tried such a shallow container. Thanks for the help!

Pic 1 = The new water garden
Pic 2 = Overall height of water garden
pic 3 = Grow / flower area
pic 4 = Clone 2 / first mother plant
Pic 5 = Clone 2 root system

6 inches is plenty, the roots will spread out to fill any space it needs.

Thanks for the reply Nodrama!