was thinking as i looked through these post, we need pictures. it takes a while to look at a post then look up whats in the post.
thanks for the look inside your GH MoonShadows , one thing i noticed that i had in mind was the use of Styrofoam boards.

When we were building our greenhouse, we had the big styrofoam sheets put in the walls and in the ground to help insulate it.

Wish I had done that from the start, Karen.

It would be hard to retro fit it, but I guess it can be done. I remember that stuff costs a fortune. Is it expensive in your area too? I hope it's worth using.

I thought my new screen door would help keep the temperatures from being too hot. For some reason, it hasn't made any difference. I am getting to 105 F. this summer. Last summer it was 103F.

I put Reflectix on the north and east walls up to the roof and on the south and west walls up about 3 feet, but to put insulation under the floor is too much of a project. Hopefully, there is a Growing Dome in my future.

I sure hope so! Take some pics when you go visit those Rodale domes.

I didnt retro fit, I put them up on the outside. I know, not ideal. But better than nothing? One day I will formally insulate the North wall properly. I think $25/sheet here?

lilnemo2, I've read that if the CO2 is boosted that it can overcome a low light situation. It said the air is about 300 parts per million and that plants slow down at 220 ppm and cited a study from Colorado State University that showed great increases in production with 550 ppm with their bibb lettuce and tomatoes. One told of using rabbits to raise the CO2 and that professional greenhouses jack them up to 1 to 2 thousand ppm. He quoted Micael Saxton of Harvard and an experiment with cucumbers.

60% shade..........64% yield
Full sunlight......100% yield
60% shade + CO2........92% yield
Full sunlight + CO2.......147% yield

Not sure what the CO2 was in the study but finding ways to add extra CO2 may compensate for the decreased sunlight. I am in Michigan but zone 5b. Trying to come up with a greenhouse that is as self sustaining as possible and hope to have some type of animals in it for the extra carbon dioxide. Maybe some call ducks! Bug control too! Sorry for making that so long and drawn out!

Thanks for the great video of your hot water storage system, MoonShadows.

I use a 4x32 (Hizer or horizonal riser) foot DIY solar hot water panel for heating my home. As long as your panels are oriented to drain back, you could move yours outside if you needed more room inside. Mine uses 1/16" polycarbonate sheet for glazing, and use the aluminum fin over copper described on builditsolar. It was cheap and easy to build and works very well on sunny days regardless of outdoor temperature, but doesn't produce on cloudy/overcast days as evacuated tube systems will.

Your use of water under the grow table seems ideal, and I'm thinking of doing the same. I just wish I could find barrels or IBC's 36 inches tall!