Low Pressure

[kevinhardy]

I use 2 Triton II filters to filter water for my drip irrigation system. Water is suctioned from a pond passing through one filer then into the other before entering the drip system. I backflush each filter using the clean water to rinse the sand in the dirty filter. Recently, sand was being pumped through my irrigation lines and I discovered a lateral was broken in one of the filters. I took both filters completely apart, cleaned them with bleach and wire-brushed the laterals to get everything back to its original condition. I expected the pressure to be the best it has been since the unit was new. However, the pressure does not appear to be as great as it was before taking the unit down. The only difference between the current setup and the previous setup is I used about 50 lbs of pea gravel in each filter this time while I used only filter sand previously. The reading on the pressure gauges located on the top of each filter is between 50 & 60 PSI but the discharge 300 feet away is low. I noticed when installing the laterals some of the lateral vents were in the upward position while others were in the down position. I don't know if this has any bearing on the discharge. There's about 100 lbs of sand in each filter. I thought I might remove some of the sand and see if this helps but wanted to ask and expert before doing this. Can someone help me determine why I don't have the discharge pressure that should be available?

[Gruffalo]

Could there be scale buildup in the laterals or in the piping between the filters and the drip feeders? Perhaps your cleaning dislodged something that has clogged the line further away from the filters. How is the flow coming out of the 2nd filter? Can you check this?