Koiphen.com goto the construction forum.
there are many folks there, that have ponds. (mud or liner ponds) and many folks have enough filters, that it requires a sump, to drain all there filters to. and then use a trash pump that can handle solids to send the waste water / fish poo up to a garden hose. so they can water there lawn / garden / trees / flower beds.
due to they are using water with fish poo and like mixed into the water. there is clogging problems that have to be addressed. and that is. providing ""clean outs"" every so often. so they can run a "plumbers snake" or garden hose down the pipes to clear out the mess.
generally these folks use a trash pump that can handle say 3/4 inch solids. some have gotten by with trash pumps that can handle smaller solids. while others. get trash pumps that can handle larger size solids. due to they also send leafs and twigs directly to the pump to get crunched up and sent out.
becuase of larger size muck being sent out. folks have taken pvc pipe or flex pipe. and simply drilled holes to accomodate the muck coming from the trash pump. vs trying to even think about sprinkler heads. sprinklers can clog rather fast. if you don't have half way clean water. some folks have taken a drill and made the holes bigger on them though.
while others, have just used a regular end cap that fits over the pipe. and driled holes into it. to create a DIY sprinkler head.
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as far as plumbing goes. i would not place things on a grid.
but rather for example run a hose to each sprinkler and then run all the hoses from each sprinkler back to a common area were you can setup a manifold. manifold being a bunch of tees / wyes. and in your case ball valves or gate valves
if ya don't do the manifold. you will experience sprinklers nearest to the pump getting majorty of the water. while sprinklers furthest way seeing hardly any water form them.
if ya try and do a single main 2" pipe for example and place a tee were ever. you want sprinkler. ((see above about un even flow of water to sprinklers))
also by making a single spot were all the valves are. it is much easier to protect the valves from "lawn mower" weedeater, hot sun, and the cold.
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as far as strainer out in the pond. you will be most like having an ugly face a few times. more so due to weeds and vegitation in the water plugging the strainer up. my suggestion would be, getting some sort of float. perhaps old propane tank that is completely empty. and use a chain (not a nylon rope or other type of rope but a good chain) to hook to end of strainer / pipe. and then also tieing on a couple concrete bricks to end of pipe with some chains. this will allow you to get the strainer out past the weeds (4 feet or deeper areas of the pond / lake. and keep the pipe from moving up into shore on you. while also keeping the strainer up and out of the mud. ((assuming pond = a mud bottom pond/lake))
pending on type pipe you go with. you may need to make a couple saddle bags or something to place over the pipe as it enters the water. to help keep the pipe down under water. so you don't have to see the ugly thing.
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without knowing specs or rather ((GPH gallons per hour or minute to head loss chart for the pump)) it is rather hard sizing pipes for ya. but on general rule of thumb. go with 3" pipe between strainer in pond and inlet on pump. with exception of the last couple feet reduce to 2" on the pump.
on the outlet side running to manifold. it depends on distance it will most likely be either 2" or 3". to manifold. then from manifold to sprinklers 1/2" to 3/4" maybe 1" depends how many and length of pipe.
forgot to add, you will most likely either want a foot valve or rather a check valve. right after the strainer. and then a tee just after the pump (between pump and manifold) so if you need to prime the line with water. you can do so.
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as far as pumps and like. even cheap trash pumps for 100 bucks. should work for ya. granted you may not be able to run / water everything at once.
if you end up going with a pool pump, or well pump. and you always want pressure within the water lines. then you would need a tank like a well tank. to deal with pressure switch for the pump and keep the pump from doing rapid on/off doings that could quickly kill the pump. or rather the starter for the pump.