Which Salty shrimp product you get depends on what shrimp you will be keeping. GH+ for CRS, CBS, Taiwan Bees (ie. Caridina). This product will only raise and keep GH at a certain level. GH/KH+ for Cherries, Rilli (ie Neocaridina). This product will raise and keep both GH & KH at a certain level. Mineral powder and Enlive are used in a new tank. Sprinkle these on the bottom of the tank before adding substrate. They are also products that are meant to be used regularly. A little at water change times is a good regime to follow. The amount to use should be on the bottle/packaging. I usually use a little less than the recommended amount. However, this is where your test kits come in handy. For example, if your TDS reading is 300, you don't want to keep adding the usual amount of Salty Shrimp, instead you should not add any at water change to try to reduce TDS. Similarly, if your GH reading is too high, reduce it with pure water change without adding GH+ additives. Enlive is a bacterial additive, that does not change water parameters. So you can safely add this regularly to maintain a healthy tank. Mineral powder replaces lost minerals, so again, this can be used regularly.