Low Ph, Kh, & Gh from tap well water.

[JenTheDroid]

My betta fish died yesterday so I’m wanting to somewhat start over and consider a group of fish. I have a 20 gallon long, with plants that seem to be melting. I was so focused on ammonia, nitrates, and nitrites that I haven’t paid attention to Ph, Kh, and Gh. 

My Ph from the tap is less than 6.4.

My total hardness is 25 mg/l. 
My Kh is less than 40 mg/l. 
 

I was interested in getting guppies but I need to get my water where it needs to be. Everyone says not to chase Ph but I need to do something if I want other fish. I also have a mystery snail and he isn’t looking so hot. I’ve bought crushed coral for my filter but I’m not sure it is a good solution since my waters parameters are so low. 

[gardenman]

The crushed coral will help you a ton. That should help with most of your issues. It'll take a little bit of time, but it's safe and effective.

[quikv6]

I have very similar tap water to you. The crushed coral will help, but you may need a bit more to further supplement GH specifically. You can add wondershell and/or Seachem Equilibrium (or Replenish, if it is not a planted tank). Livebearers seem to thrive with minerals/hardness.

 

[Patrick_G]

You have excellent water for many South American fish. Tetras, Rasboras, Corydoras, Rams, Angelfish or many more.
You can still keep livebearers by raising your GH/KH with crushed coral like @gardenmanmentioned above or using Seachem Equlibrium, a power that’s mixed into the water before adding it to the tank. I’ve tried both and find the crushed coral easier. I put it in a filter sock and put that in my hang on back filter or hide it behind some hardscape.  Cory recommends sprinkling it on the substrate at one pound per ten gallons.