I'm getting guppies and mollies in a new tank.

I've read that their water is supposed to be brackish - how much salt should I add and what brand or type?

I found this when i was researching:

"Freshwater fish and plants have evolved to live in an environment that has very little salt, and because of this some are very sensitive to salt.  Most freshwater plants do not tolerate much salt at all, and if you are trying to keep live plants, salt as a general rule should be avoided.  Some species of fish from very soft water, like Plecostomus (Sucker Mouth Catfish) do not tolerate much salt either, and the addition of salt with these fish should be avoided."

Is that true?  Should i add salt or not?     Also what would be the ideal hardness level and ph level for them?

Thanks for any help!

ok thanks!  How should i raise the ph level in my tank?  It's not high enough

There is a special mineral salt available, intended mainly for African Cichlids from lake Malawi and Tanganyika where the water's really hard and alkaline. This shouldn't be making the water brackish, but it should be enhancing the hardness, so you could ask in a knowledgeable pet store about the product And if you get it, be sure to follow the instructions on the package!!

There are also some things that will help with the pH level (and sometimes carbonate hardness, kh) in your tank. It's usually sold in bottles as a liquid, but there are also some sort of tablets available that will control the pH for you while they dissolve. You could also ask in the shop for filter media or substrate material, as there are certain minerals in some substrates or pebbles that will also enhance the pH and hardness of the water.