RO Water, LLDPE & Ice Makers

[rural_engineer]

I've installed a reverse osmosis filter with a permeate pump and a 20 gallon tank in my crawlspace. I've got five drinking water taps throughout the house that I've plumbed with 3/8" LLDPE and John Guest fittings in the crawlspace. All of the tubing is visible for inspection. Everything seems to be working really well. Pressure is good and my TDS are down about 90%.

I have a couple of concerns:

1. How durable is the LLDPE tubing? Long term should I be using something else?

2. I'm adding an icemaker to my freezer. The icemaker instructions say to only use copper to connect to the solenoid valve, and to not use polyethylene. The tube coming out of the valve going into the icemaker is, of course, polyethylene, so I'm taking this with a grain of salt. Is there any reason not to run the LLDPE directly to the icemaker valve, assuming the correct fitting to connect it to the valve?

 

[rural_engineer]

Additional question: Do I need to worry about water hammer from the icemaker solenoid? I'm operating on a 50/70 well system with a permeate pump, so the RO pressure is pretty high.