The first one is run by Imke so I sent her a question yesterday asking how do people mix tigers and CRS when both require fairly different parameters when it comes to PH. She already posted an answer today and answered my email...that was nice. (http://shrimpsider.wordpress.com/201...-and-ph-value/)
Cool that she posted your question and answer online and shows the adaptability of the shrimp as well. The first generation or two, shrimp may not do as well in different water, but they can adapt. I think mineral content and the water being harder or softer, for shrimp like CRS, say, is more important that the overall pH.
I've talked with Polish breeders who don't have access to RO and have like 8-8.5pH but soft mineral wise and are keeping tanks full of TB's in them. I know TB's in 8.5pH sounds crazy but if the temp is cool, which they like, the gH is very low, they seem to do fine.
Part of my experiment right now to get a way from active substrate and multiple canister filters and all that stuff and see how well mine do in just RO water with some minerals.
20g platy, , 2 x 10g shrimp, 3 x 20g shrimp, 7.5g shrimp and 1 great dane/mastiff puppy.