OK, so reporting back on the Engel vs. the Igloo. The engel kept temp below 68 for 49 hours. Igloo kept it for just under 24h. This was with no plants, R/O water, air running and a normal light cycle. I am not sure its worth the cost, but I had a spare engel.
Cooler res update:
Im not one for posting too many pics, so Ill try to describe this if I can. I made a slight modification to my cooler res that is AWESOME. I has having trouble figuring out how to get inside my cooler to place the bottles if I Scrog (using the cooler lid instead of the foam...Is there any reason NOT to use the lid and use the foam instead on the igloo marine?). I cant see how I would move the lid much without moving the entire screen. I came up with a great idea and it took $17 and about 20 minutes.
1) Find a common bottle size you want to use for your ice, measure Diameter.
2) Go to your local hardware store and find a size PVC pipe that is larger than your bottle. Get 18"pipe, one threaded end cap.
3) Go home and cut a hole in the cooler lid that is the same size as the OD of the pipe
3a) I used two small pipes, the size that would fit a standard nestle water bottle. I put them in opposing corners to even out the cool effect a little.
4) place the pipe into the hole with the threaded end cap sticking out of the lid. The threaded end should stop the pipe from going all the way through.
5) Cut the pipe to desired length. two options I have tried
a) cut the pipe so it is about 1" shy of the bottom of the cooler when its closed, drill it full of 1" holes ALLLLL over
b) cut the pipe length so that it is about 70" of the height of your ice bottle off the bottom.
This allows me an easy way to manage my ice bottle. With the res full you just pop the cap (I only put it in 1/2 turn) and drop the bottle in with a retrieval rope on it). When its time to change, no fishing for the bottle. This way you dont have to remove your lids. This also provides nice access for filling, topping off, sampling water, etc. I made the first one big enough for a 2L bottle, that one you can get your whole arm in if you really needed to.
The only thing I am going to try different next time is cutting the plug at a 45 degree angle with a saws all. It wont be as pretty, but the plug you cut out could be used to make the "cap" so you wouldnt loose that little bit of insulation in that spot.
This worked AWESOME, if you guys are interested Ill see if I can get some pics up.
PS
Flo or BB57, you guys have any reason to not use the original cooler lid with foil tape on it? I taped the whole outside of my cooler anyway, boredom and I thought it might reflect a little bit of radiation.