ok i just got some more info.i figured if you knew a little about the setup you might be able to help him.he has a dwc setup with 2
2x3 trays.on benches about 20" off the ground.they have a fill/drain connecter at the end of each tray ,they are connected with general hydro blue tubing via T fitting then one line goes into the rez to the output on a pump which is on the bottom of the rez.he is using 6" mesh pots w a rw cube with hydroton filling the rest of the pot.

he uses a 400 and a 150hps

he has already had success with this exact setup,i figured it might be important to know that too.
when the system runs a cycle it starts to fill the 2 trays,it takes about 6-8 minutes and then another 8-9 to drain back into the rez.ph is perfect 5.5 nutes are never mixed past half strength.
he is using dynagrow grow for veg. then dynagrow bloom these are very easy salts to work with from what he told me.o n he was using the dyna brand protect silica at 2 tablespoon for 25 gallons a very small amount.bloom was mixed at 1.5 teaspoon per gallon respectivly.there is a fan,he had spidermites n got some ooths to control them naturally because he dont never use poisons.
so when the water pumps into these trays it can fills the tray to the top of the mesh pots then they soak a few mn then drain.
it seems like a very simple setup to me, one time he said to me that if he sat on front of them and watched them for 6hrs he could see them growing.whats the proper way to flush the salts he said he used regular tap water to flush then for 24hrs then went back to 1 teaspoon bloom.
as for the odor he said he smells almost nothing in the room he said the rez has more odor then the plants.

let me know what you think,he mentioned clearex he said he seen in the internet.