Bottom-watering troughs for 8x6 greenhouse (Bernards Heath AL1)

These are 50 x 100 and 50 x 190 cms. The larger one fits on a standard 3-bay stand. The smaller one at the end of the greenhouse. I've used these to maintain a constant depth of water to cultivate tomatoes and strawberries. They worked, but the base of my greenhouse is not level which made them tricky to use, so I have reverted to drip feeds. You can see the control floats at the top left of the troughs. The black material stops algae growth and keeps the fruit out of the water. Will deliver within St Albans.