When i started keeping shrimp a few months back i had the same problem. I decided to change to RO water and it works wounders, you still have to reminalized it and i use shirakura ca+ ever since i stared doing that i havent lost a CRS or any of my neos. i keep my TDS between 150-170. Ammonia, Nitrite, Nitrate at 0. PH between 6.2-6.5. i would recomend you to use RO water and a reminalizer this would be a good start for your tank. keep us updated.
I will say that certain parameters will encourage breeding, but stability is more important than anything. As long as you drip acclimate your new shrimp to give them time to adjust, they should be fine, even thrive, no matter you're parameters (within reason of course).
Seriously though...RCS are pretty undemanding. Personally I have found that they (mine at least) don't like low pH. At 6.5 there was no breeding, not even saddles. I moved them to 7.6 and they breed. I'd say above 7 and they are good.
TDS...what you have it fine. There are some that have TDS in the 300's, even 400's and they do well. Speedie...our resident shrimp God I think says his yellow neos do best as TDS in the high 300's or into the 400's.
Temp, low 70's is good.
Ammonia of course should be ZERO.
Nitrites again, ZERO.
Nitrates, keep them low.
You'll see RCS have a very wide range of acceptable parameters. Like said, stability is more important with these particular shrimp but you do have to watch out for extreme ranges and just see what works for your shrimp. They are not all the same.
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