I saw your post and it seems like we have similar setups. I have mine completely covered with plastic wrap, but I open it up for about 15 minutes each day and then mist the plants (mainly the ones in the back and on the slopes, less so for the ones in the front which already have lots of water). Based on the information I've been able to get online I would guess that my light is giving the plants somewhere around 60-80 PAR. I also used HC that was grown emersed, so it works really well for DSM. Submersed HC would (I think, correct me if I'm wrong) take a couple weeks to change into emersed state before you see much spreading, so if you used that it may explain the delay.