What you see above is organic debris that started to clog our nozzles a couple of days after the first injection.
Since we could not find anyone else who has injected the compost tea on this scale, we had not been warned of such a problem. All of our heads worked properly and these nozzles were in the ground for years with the occasional clogged screen here and there. What you see above are Hunter MP-Rotators, the 1000 and 2000 size head. They are basically miniature rotors the retrofit into existing pop-up spray heads and have screen sizes to match each level, 1000 having the finest mesh size, 2000 having a slightly bigger size and 3000 having the biggest mesh size. We initially didn't put two and two together until we started to actually find complete irrigation zones where these MP 1000/2000 nozzles were all clogged solid. The only time you may see this naturally is if you just had a large irrigation break and large amounts of debris were put into the system. That had not been the case in all of these location.
We worked pretty hard to make the repairs we needed, which actually turned out to entail replacing about 750 of these nozzles all throughout campus. Then after some conversation and brainstorming we realized that the clogging happened just after our first inject of tea. We were not positive since we did not inspect every station prior to the injection, but the amount of clogged heads would have been noticed in advance of the first injection, so we theorized the tea caused it somehow. So prior to the next injection we went to the majority of our MP 1000/2000 zones and inspected them to see if they were in good shape as a baseline.
At the same time we had another theory going. Since almost none of our MP-3000 zones clogged we thought that the screen size of the 3000 series head must have been just large enough to allow this organic debris to flow through and out of the head. We purchased a few 3000 screens and placed them on the 1000/2000 series heads. Of course we were not very confident because there must be an engineering reason for the screen sizes based on the small gears inside the head, but it was worth a try.
We went forward with our next injection after establishing our baselines prior and we were able to confirm that the compost tea injection was somehow freeing up this organic matter and allowing it to flow down the system. I believe that the tea product itself is not at a concentration high enough for it to be the clogging agent, but instead the bacteria in the tea eats away at organic material on the inside of the pipes. Irrigation mainlines are really no different than rivers or streams in that there are dead spots and locations where water swirls and stays in place as water passes by. After the injection there were about 12 hours until I ran another cycle the next night to "flush" the system out. I believe during that time is when the majority of the organic matter is freed and travels through the system.
Once I had a good feeling and understanding of what was going on I spoke with our compost tea guru. He initially believed it could be a real possibility but then he spoke with a bunch of his colleagues and they all believe that what I'm describing is a result of the bacteria eating away at the organic matter lining the irrigaiton pipes.
We have done three injections now and every time, like clockwork, we are getting this result, each time with less and less clogged heads. We are changing out many of the screens to the MP-3000 screens which has helped tremendously with this organic clogging. We believe losing a few heads to true debris is acceptable while allowing this organic matter to flush through.
After all the work we have done building, testing and now injecting, we think we have found all the pitfalls and have started to make adjustments to account for them. I still believe we made the right decision to inject this product and although there have been headaches, it has and is still very rewarding to do something in a way nobody else has.