08-22-2014, 02:42 PM
So what does a tank cover do? The manual from the state really advocated having a solid cover, not sure why because to a large extent whatever falls on the tank also falls on the roof and makes its way into the tank eventually. One difference though is that if you have installed a first flush device then the roof water is a bit cleaner.
Everyone uses shade cloth and no one seems to die so seems like a porous cover is OK. What does make sense is to prevent the cover from sagging into the water when the tank is full. I built a tank out of a couple of 5' x 16' cattle panels and some 6 mil black plastic. When done I put a 10' x 10' square of shade cloth over it stretched drum-tight. It fit perfectly and only cost $25 although I had the shock-cord ties already. Instead of penetrating the bottom of the tank I put the 3/4" pvc suction pipe over the side and down to where the side meets the bottom. I used a socket x 3/4" female thread elbow on the vertical and a socket x male thread fitting on a horizontal section reaching to the center of the tank. I jammed a water filter over the plain end of the horizontal and plugged the other end of the filter. I suspended this end of the pick-up pipe from an inflatable ball so that water is drawn from about a foot below the surface. The threaded fittings, greased with silicone grease, act as a hinge. When the tank is full the ball lifts up on the center of the shade cloth to prevent a birdbath from forming.
Everyone uses shade cloth and no one seems to die so seems like a porous cover is OK. What does make sense is to prevent the cover from sagging into the water when the tank is full. I built a tank out of a couple of 5' x 16' cattle panels and some 6 mil black plastic. When done I put a 10' x 10' square of shade cloth over it stretched drum-tight. It fit perfectly and only cost $25 although I had the shock-cord ties already. Instead of penetrating the bottom of the tank I put the 3/4" pvc suction pipe over the side and down to where the side meets the bottom. I used a socket x 3/4" female thread elbow on the vertical and a socket x male thread fitting on a horizontal section reaching to the center of the tank. I jammed a water filter over the plain end of the horizontal and plugged the other end of the filter. I suspended this end of the pick-up pipe from an inflatable ball so that water is drawn from about a foot below the surface. The threaded fittings, greased with silicone grease, act as a hinge. When the tank is full the ball lifts up on the center of the shade cloth to prevent a birdbath from forming.