Cal/Mag/Alk Where to start?

[Aquattro]

For now, frags won't take much Ca at all, so regular water changes will be enough, although IO is a bit low out of the box so you might want to add a bit of Ca (I use seachem) to your new water. Get a better kit, I like Elos or Salifert, and once the water changes don't keep up, you can start thinking about adding Ca/alk. But you should be good for a while yet. Best way to tell is get a reading after your water change and another just before the next one. See what the difference is. As long as you're above 380ppm, you're fine.