Floating Tray DWC

so ive got an 18 gallon reservoir with a 3inch thick piece of Styrofoam (which has holes cut it in for net pots) ... i have 4 tubs like this, 2 in veg tent and 2 in flower tent...the plan is 3 weeks in each tub so as to have a harvest every 3 weeks... i started some ww from seed and just took some clones (which i will sex ...than clone corresponding mothers to start the system)... im fairly confident that i have most of this set up well because the plants that came from seed are growing INSANELY fast...

i have a few worries though... first off i just did a res change a few days ago and noticed some algae and/or slimy stuff on the inside of the res...the roots were clean and white...but the res was gross.... is this normal????

also there is some light that is able to hit the water because the tub bows out with the water weight making the floating tray not sit flush with the sides....will this cause a problem as the grow goes on??????...... is this also why my humidity is over 50 percent?????????

also because the tray always sits on top of the water the bottom inch of the net pots is always submerged ....will this create a problem in the future??????

would i just be better off to cut holes in the lids that the lids that came with the tubs and ditch the floating tray all together?????? i saw a video on the tray thing decided to give it a try but now im wondering... anyone else know anything about this tray method??????

also a sidenote that has prolly been answered.....is there a simple way of knowing if i have the optimal amount of bubbles?

Light hitting the reservoir is a NO NO! Correct this issue quick! Your humidity is high because the temp is rising in the grow space causing reservoir to evaporate, that & the light hitting it speeds it up. You don't want your net pots completely submerged, 1" below is where you want it.

Ditch the floating tray and either get a bigger piece to cover the reservoir completely and block out all light. The net pots will need to be covered later and filled with hydrotron rocks if not already done.