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crusshed oyster shells to harden water?

3631 Views 3 Replies 3 Participants Last post by  discuspaul
Hi, I started a guppy tank about 3 months ago. I've added plants and driftwood, but while i knew the wood would soften the water, I didn't realise guppies prefer hard water. I was also recently given a couple of mystery snails. My normal tank pH is around 6.5 and GH/KH are usually below 20ppm. I was advised to either remove the wood (already planted with moss and ferns) or add crushed oyster shells.

I have decided to go down the oyster shells route. I have a 70L tank and today washed and sprinkled a couple of handfuls of oyster shells over my substrate. How long after adding oyster shells can I expect to see a change in the water parameters?
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No experience with oyster shells, but the speed will depend on how well it is crushed and whether it is placed in good flow or not.

Also, the snail shells will erode and they'll die if you can't get the pH above 7 (in addition to upping GH).

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Yes I was worried about the snails and this is why I am trying to do something about it. I've only had them a week... I don't think they're dying just yet. *fingers crossed* Just curious if anyone has had experience with oyster shells. Some say put it in the filter, and others just say to add to substrate. I've obviously chosen the lazy option...
Shells will raise the pH but over time may continue doing so - beyond the pH level that you want to maintain.
So best to place shell fragments in a mesh bag with a string attached so you can remove them when the pH reaches a point that is too alkaline.
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