Economical remineralizer?

[cmo1922]

Hello! It's been awhile since I've been on the forum! A couple weeks ago, I made a big move where I had to give away my 29g and 10g to a friend. I kept my 20g long (transporting the whole thing intact with about 5 gallons of water in it, in our car all the way from FL to the Northeast...I know that's a terrible idea but so far no leaks about 1.5 weeks later). Lost every single ember tetra (I'm sure they died of shock) but all 7 of my corys, my honey gouramis, and my shrimp and mystery snails seem to be doing great. 

Anyways, I've moved from an area with moderately hard water (gH of 13-15, kH of 5) to a location with very soft water (I'm getting 0 ppm reading for both gH and kH on the Tetra test strips, and I'm seeing absolutely no hard water stains anywhere in this house). I keep neocardina and all sorts of snails so I need to get to at least gH of 4, and I want some buffering capacity too.

What is the most economical way to remineralize using a commercial aquarium product? I just want to buy something easy with clear instructions. I bought some wonder shells...3 smalls dissolved completely in less than a week 🙂 I will likely do water changes twice monthly.

On another note, since I've been given the gift of seemingly RO quality water, I'm going to try my luck with crystal cardina shrimp using the tap water. I've set up a 6 gal tank with Stratum, some low light plants and mosses, and a seasoned sponge filter. I plan to remineralize to about 5 with a gH+ only product. I'm going to wait at least a month to let everything season before adding shrimp, ghost feeding and adding occasional Stability along the way. Any other tips or things I'm missing?

Thank you for your time!

[Mmiller2001]

As @Pepere says, I’ll include that using CaSO4 and MgSO4 versus a commercial product produces the least amount of TDS, a good thing.

If you want to dose KH, using potassium carbonate (K2CO3) is the cheapest and is readily available on Amazon. 

[cmo1922]

Thanks everyone! In a few years I plan to start my dream tank (large planted angelfish and fancy pleco tank), and knowing me, I'll have multiple tanks! So I will def do the individual salts then to save money! 

For now, I'll probably do the equilibrium since I just have the 20g and 6g to dose and I'm wanting to keep things simple. I may do a little alkaline buffer for the 20g. I recall having trouble with my neocardina and nerites when I lived in an area with extremely soft water before if I didn't dose the buffer.

The wonder shells just seem too unpredictable if you have very soft water. And not cheap!