Update:

Transplanted 5 of the big plants into their final destination, 2 gallon pots. The 3 smaller ones I've left in their current pots until they get at least 6 inches taller.

With the house at 75 degrees, the hydrohut is running at 76.8 degrees. Not bad. I can deal with running between 76-81 degrees. I will time the lights to run mostly when the room being used is not in direct light.

I need to clean up the room but I will take pictures tomorrow of the entire setup. I need to buy more flexible ducting so I can push the hydrohut into a corner of the room so I can fit another one in there in the future.

I am very pleased to have solved this problem. Apparently my last apartment was so efficient at cooling I had never realized that the space I was using was actually too small for a 400 watt light.

I hope I'll be able to cool a 600 watt efficiently. I'll be ordering a 600 watt light and cool tube very soon so I can start flowering.

Before transplanting I fed the plants as follows:

12ml Canna Coco Nute A
12ml Canna Coco Nute B
6ml Calmag
PH'd water 5.8
10 oz of water each plant