My new trays arrived today. I had ordered two from Amazon and two from Greentrees Hydrophonics. Amazon only sent one tray, which was fairly beat up, and will evidently send the other tray later. The Amazon tray had obviously been bent, and the corners were also bent. The two trays from Greentrees were of different sizes. They are also larger than advertised, as the listed dimensions were the interior dimensions. They are 7 1/2″ across, which means that I can barely fit two of them on my shelves.
They are pretty large, and have a drain on the bottom which makes one end higher than the other. I will have to do something with the drain, either remove it, or prop up the remainder.
I have decided to forgo the automatic watering part of my design, and only build out the drainage portion. This will let me water the plants in place, and also vary the water (with KelpMax, etc.) for each plant. We’ll see if this works first.
I think there is enough for my experiments however.
[Later post: After working with these trays for some time, I decided not to use them. They are good if one has a fixed tray length for their application (like sitting on top of a hydroponics tank), but for my application, where I have several lengths necessary, they were not going to work. They were also too deep, and needed to be cut down. I decided to build my own trays to size with PVC sheets.]