The filter blows the down onto the DHG is that a problem?
In my experience and from what I have heard from some of the guys on here, yes. It doesn't give the plants time to absorb nutrients. You don't necessarily need to dose CO2, dosing with ferts and a good "enriched" substrate should be adequate (e.i. eco-complete, flourite). For the lighting a bulb that's 6500k should be good, but like a zoo med ultra sun if the hood is T8. You really don't need to switch up to t5s, they are really expensive and your plants can do just fine under a t8 bulb. Just change it yearly. In my 75g I run GE/phillips 32w 6500k bulbs, but in my 29g, I use the zoo med ultra sun 6500k. Good luck! I'll follow your thread cause I'm going to be adding it into my 30, so any experiences you have would be great to know.