Irrigation system for a large (still) empty plot

I am still not finished. I have now completed 8 out of 15 circles and still have a bit of digging ahead. The day before yesterday, I finally sowed a few square meters of lawn. You have to see some progress now and then. I had already tested everything, but only tested and not for 20 minutes. Unfortunately, it has now turned out that something is not right. At the beginning, everything runs well, but after a few minutes the flow obviously decreases until eventually the sprinklers retract. I have 4 sprinklers on one circle with a total of about 1.7 m³/h. After 2 to 3 minutes, you can see that the range decreases and then slowly continues to decline until after about 8 minutes the sprinklers start to retract. Earlier, the well driller was on site and looked at the whole situation. (Since I am at work, only my wife was there.) According to him, his delivered pump delivers enough water from his drilled well (supposedly 2m³/h). But I have a filter directly behind the pump in the main water line; he quickly removed it and shook it, and afterwards everything ran great again. Therefore, he said it is probably the case that the filter clogs up due to high iron content or something similar. According to him, it would be unnecessary anyway, since the water is sufficiently filtered by the filter gravel at the well end. Question 1: Is that correct? Is the simple filtration by the filter gravel (I think it is 4m) enough? Question 2: Could that be the explanation why the flow decreases? So can the filter clog up during operation if the pump runs continuously for 15 minutes? I would have expected that rest phases without water consumption are necessary for clogging. PS: It is a disc filter: Irritec disc filter 1" male thread on both sides with integrated flushing valve, max. flow rate 5 m3/h, 120 mesh, pressure rating PN10

Take the filter out and then let it run longer. If the particles are small, they will simply be flushed through. That wouldn’t be really bad. If they are larger, they will be stopped by the sieve in the sprinkler. The sieves are quickly cleaned...

Iron or manganese?

Manganese deposits everywhere and can really clog pipes.

Well, quickly removing it is easier said than done. Then I’m missing 15cm of pipe. I’ll have to see how I can manage that.

Iron or manganese? No idea. The water did smell, but only at the beginning, I think. I have to keep an eye on that.
I think it’s iron because I have 2 sprinklers very deep in one zone. So deeper than the valve box, and some water also leaks out there when the zone is turned off. And the whole sprinkler is now discolored reddish-brown. I hope the nozzles can handle that.

PS: Back when the well was drilled (last year), it also smelled briefly at the start, but not anymore after that. The water was hardly iron-containing either. After that, I have to shorten the pump pipe by one meter because a shaft was set around it and now it’s under the garden shed. So I shortened the pump pipe and also the PE pipe that the pump is attached to. If I didn’t shorten both equally and now the pump is hanging 50cm lower or higher than before, can that have such effects?

Mangan deposits as a red/brown to black crust. It becomes really hard and firm and can clog nozzles and valves.

Yes, that's how it looked last month when I did the piping from Presscontrol to the filter directly in the shaft.



That looks more like your description/manganese. Well great. What can be done about it?