@dmallia,
Most shrimp keepers use Salty shrimp to remineralise RO or rain water, as this type of water is pure and devoid of the natural salts for living organisms, we add these salts back to a suitable level for the type of shrimp (or fish) we keep. That way we can control the water parameters exactly to the most ideal parameters for what is in the tank.
there are many alternatives to Salty shrimp.
Mosura have one called Mineral Plus Ultra.
Shrimplab have a product called GH+ Mineral Salt.
Dennerle have a product called Shrimp King Bee Salt GH+.
Borneo Wild have a product called BorneoWild GH+.
They all work the same way to remineralise Reverse Osmosis or rain water to the right TDS levels. Most are in a dry form that you mix with your change water, except for the Mosura product. Mosura's Mineral Plus Ultra is in a liquid form that you drip into your change water, so it's easy with no mixing required. But all these products assume you can measure the exact amount you need by using a TDS meter. So you will need a TDS meter to measure out approx 150 TDS for Neo Caridina shrimp.
If you need to learn more about TDS and how to measure it, I have an article on SKFA you can check out...
When you are more comfortable and want to start making your own, I have an article here for your own DIY Remineraliser mix...
hope this helps.