This is the final version ( for now) I have decided to go with. The three pumps are now all on this MkIII version. All I need to do now is introduce my seedling Darlingtonia to the Sphagnum baskets. I'll be slipping in a few pots of Cephalotus too.
Water pump No.4 is now in operation. It has replaced the sole surviving solar air pump in the initial, now abandoned, air pump trial. I found a much cheaper supplier for the T connectors (and the L connectors) but the diameter was slightly larger. I fitted the tubing by heating in boiling water to make a good tight fit. I then discovered that with the larger diameter I could make the spray bars from giant chunky drinking straws (they come in packs of 30). They're very cheap and easier to work with than the tubing so another bonus. I should be able to easily adapt the narrower diameter T connectors to take these when spray bar replacement is needed. As I had a base already made for a solar panel as supplied with the air pump I adapted the design to fit in the water pump panel. This I feel is superior to the ones already fitted to the other three panels so I'll probably replace all those at some stage. Tray No.1 was the only one with the pump station in direct sunlight and this did lead to a need to clean out thread algae this week in the gap between the two rearmost inner trays as it was beginning to affect pump efficiency. I made up a plastic cover to restrict sunlight to prevent this in future. A second cover is over pump No.4 as that will develop the same problem if prevention is not applied.