Water temperature makes a difference in all aquaculture systems, and as this short video from Murray Hallam in Australia shows---it can make a difference to your lettuce and therefore your profit. I really like Murray's videos--they are straight to the point and make a lot of sense. I enjoyed this one because he's admitting a mistake. In this video, he share's moving toward deep water raft systems, and away from his long skinny pipes, as a way to better control water temperature for a lettuce crop. He also stresses the importance of rotating your seedlings and harvesting on a specific schedule.
Farmers...take a peek and let me know what you think. You might also want to remember to not just check the temperature in your fish tank... If you've got lettuce--check it at the end of the system too--see if there's a difference!
source http://www.aquaculturehub.org/profiles/blogs/aquaponic-water-temp-some-lettuce-and-making-a-profit
