Hi Cramps,

Please describe your ditch water take off system and filtering system in more detail. For example, do you siphon water out of the ditch or pump it out. How big is the ditch and is it a concrete lined ditch or more of a stream? How fast does the water flow in the ditch? Where is the ditch located in relation to where it is needed (elevation difference)? Is 40, 120 in microns units? Physically describe how the filters work? Is cost a major factor in your decisions? The pressure compensator emitters are the easiest to clog because of the torture track that the water must move through to get out of the emitter. Good for preserving pressure but lousy for keeping the emitter free from clogging. How much surface area does your filter expose to the water surface? Please start with this info and forum members can discuss some improvements or alternatives.

If you don't feel like answering questions to fill in the info gap, then I suggest you do some experiments. Try a short run with 40 filter and put a container under a drip emitter and record the depth over time. In a month do it again and see if there is a or decrease in depth in the container. You can do it more frequently if you like. Do the same with an 80 filter and 120 filter. At the end of your experiment cut the tube and look inside and see what got by your filters. Also have a sample of water sent for analysis to a soils lab and they can tell you the sizes of particles that you are dealing with in the stream. What ever you do please post your result or decisions back here on Garden Web. thanks. JMHO Aloha

When they say 140 mesh, they mean it. Sure you can get away with coarser filtration than that, but when you shut the water off, you get particles settling out. First time you realize that something is wrong is when some shrub is dying from being next to a clogged emitter. The sprayers and bubblers are less risk. It's easy to walk around and SEE that they are dripping.

Screen filters clog very fast. For a fine mesh filter you could use a disk filter. If you invest in a few bucks worth of extra plumbing you can put a bypass around the filter, so that by opening and shutting a series of valves you can back fush the filter without having to take it apart.

I also learned the hard way, that you don't let your filter freeze. So my filter is the lowest piece of plumbing and it sits in a bucket of water. A tap above it can be cracked to trickle water on the filter. This allows me to keep my filter in the field until nighttime temps get down to about -5C.

The whole filter assemble is attached with quick connects so that in winter I take the filter inside..