I decided to end the ebb and flow lettuce and basil grow as the DWC is coming along very nicely. Actually, the DWC lettuce is now ready for the first small harvest and those leaves look great!
I completely tore down the ebb and flow system as it is generally a good idea to completely sanitize between grows. Any potential root pathogens and algae will be eliminated and it also clears any remaining nutrients and salts from the pumps, net pots, tubing, and media.
I ran clean water through the system for 7 days before the intended shut down date. This helped clear salts and nutrients as well, but I wanted to experiment and see the effects on the leaves. I can say there were no visible signs of plant stress those 7 days, but I am not sure how long that would have lasted.
I cleaned all the parts in a solution of 1/3 cup bleach to each gallon of water. I washed and then soaked the smaller pieces before rinsing, and wiped down and double rinsed the tray and reservoir with lids. After cutting as much plant and root material from the media as I could, I soaked the entire batch of silica stone for a couple hours in the solution. I rinsed it several times as it is porous, and will rinse one final time before the next use. Seperating the smaller pieces of root from the stone is the most tedious part of the process, so I will let it completely dry until the roots crumble and can be rinsed away.
I was really surprised at how little dirt and grime had accumulated. The flow tubes were a little slimy, but no signs of algae or mineral buildup. Again, very low maintenance to operate and very easy to clean and prepare for the next run.
I am anxious to get this into operation with a strong batch of cilantro, basil, thyme and others.