I can't keep shrimp alive. Why??

[Kshrimp]

This is a duplicate post.  Moderators please delete.  I was having issues posting and didn't think that it posted the first time.  Thank you.

 

Hi!, I'm new to Shrimp Spot, but I've been keeping fish for 13 years. Over that time I've successfully kept various fish. Some of my original fish are still alive and well after more than a decade. I've tried shrimp on 4 occasions with no success. I've been to other forums seeking help, but to no avail. Like with fish keeping, there are a million opinions and anecdotes, but people with the exact tank conditions as me have good success with shrimp...

I've tried keeping shrimp 4 times in 2 different mature (established for years) planted tanks: amano shrimp twice, ghost shrimp and Neocaridina davidi. They all start out as what I consider normal. They are active, eating, and "look good." They are all dead within 10 days and start dying on day one. Once I was able to keep a couple amanos alive for a 2-3 months. Prior to dying, they appear and act normally, working their way around the tank grazing etc. Then they are dead with no obvious physical or behavioral signs of health issues.

I drip acclimate 1-2 hours upon arrival.

Temp: 74-5 F
KH: 4dKH
GH: 4dGH
pH: 7.5
TDS: unknown
These tanks receive a 50% weekly water change. Shrimp seem fine after the changes.
Ammonia 0
Nitrite 0
Nitrate 5ppm prior to water change.
Never have used any medication in these tanks
I've added no metalic plant weights
All hardscape (rocks and wood) and plants are natural.
Substrate in both of these tanks is Eco Complete
One of the 2 tanks is lightly fertilized (Thrive C). The other received no ferts. ( the amanos and cherry shrimp were in unfertilized tank).
Parameters the same in both tanks.
Other inhabitants are nano fish and snails( Rams Horn, Bladder, Nerite)
The shrimp were sourced from 4 different suppliers.  I must buy online because shrimp and snails cannot be sold in my state

Tom Barr thinks it's due to copper pipes in the house plumbing, but surely other people have copper pipes and are able to keep shrimp. Also my pH is not acidic, so I would think copper leaching would be minimal. If I test for copper, what level of copper is too high for shrimp? Plus, I do keep snails...

I've had shrimp keepers tell me that shrimp need small infrequent water changes. I've had others say they thrive with large water changes. I've been told they can die if they eat too much food, but I'm skeptical of that, especially since they start dying immeadiately.  Do shrimp really over eat to the point of killing themselves? I'm doubtful. 
I haven't given up. I have an empty 5 gal I'd like to dedicate to shrimp, but I am thinking of giving up and simply adding a couple dozen chili rasboas (not in the 5 gal) in place of cherry shrimp.

Your advice, comments and opinions are welcome and appreciated. Thanks!