Best way to raise water hardness

[TwoHedWlf]

I've been noticing the shells of my rabbit snails appear to be deteriorating. I checked my tap water hardness, and it's so low it doesn't even register on the test strips.

How would you suggest raising it? Is it something that must be done gradually to be safe?

It's a 90g tank with angels, horse faced loaches, and rabbit snails

I do it by filling up one of the trays in one of my filters with coral fingers. Before I had tons of that spare I used coarse bird grit in a mesh bag from the local pet ship, it's crushed up oyster shells, I think. Dissolves slowly and slowly raises the hardness and PH.

 

[RD.]

Snail lives matter, too. Someone had to say it.

 

[BassetsForBrown]

Feed them cuttlebone and eggshells

I just learned cuttlebone doesn't sink.

 

[Vukmir13]

Wondershells will work, but I’d move them to a small tank of their own. I’m of the camp, fish first, everything else second.