Best thing to do if your soil is needing replacement would be to set up a brand new tank, new soil, cycled, and ready to go for the shrimp to swap right over. That would be the best method for the least collateral damage.
Yeah, if you can do that will be the best!
(I've been thinking to get another nano tank to start a new scape this way. Then shut down the existing one and repeat the process when I want to)
The way I did it was really really simple BUT THEY WERE NEOS.
Measured the existing parameters.
I took a 3 gal plastic container and transfer the HOB, some moss and plants and filled up with tank water.
I net out all the shrimp into this container.
Then uprooted all the plants, put them in another plastic bowl and catch the last shrimplets.
Took all the fluval soil out, clean the tank and place my new DIY UGF in there, using a big strainer I rinsed the akadama under the tap before placing it in there.
Filled up the 1/2 tank with DI water and 1/2 of what was in the container with the bugs. Started the eheim 2213 w/UGF to clear it up.
Plant it up and place the rocks and all of that.
Compared the parameters, matched GH and temp. TDS and ph were off.
Transfer the Hob to the tank and "drip" (rather quick, more like "stream") acclimate the shrimp in the container.
Put the shrimp back in.
Then, weeks after, I got rid of the neos and got CRS. I monitored the water the whole time. The tank didn't "recycle".
I'm not saying that you should do this with your PRL tho. But it would work with inert substrate and neos FO SHO