Rocks

[Straight Shooter]

Just buy one small rock of each. Place in water for one week. Note pH KH GH at the beginning, then take these readings again after a week. Any change, not inert. Small change? Good enough for most applications. Big change? Maybe better for livestock that prefers those conditions.

 

[dw1305]

Hi all,

Do you think any of the rocks will be ok in an aquarium?


The cream coloured rock in the first photo is Cotswold (Jurassic) limestone, and it will raise the pH because it is pretty soft and flaky. The rock on the left looks like a Carboniferous Limestone (Black Rock series or similar), it won't have much effect on pH or hardness, because it is very hard.

All the rounded cobbles will be pretty inert, because only very hard rocks form rounded cobbles in moving water, and if the rocks were at all soluble they would long ago have dissolved.

cheers Darrel

 

[dw1305]

Hi all,
Apologies I seem to have managed to type inside the quote, my bit should have said:

The cream coloured rock in the first photo is Cotswold (Jurassic) limestone, and it will raise the pH because it is pretty soft and flaky. The rock on the left looks like a Carboniferous Limestone (Black Rock series or similar), it won't have much effect on pH or hardness, because it is very hard.

All the rounded cobbles will be pretty inert, because only very hard rocks form rounded cobbles in moving water, and if the rocks were at all soluble they would long ago have dissolved.

cheers Darrel

 

[zozo]

The last photo is a darn nice rock.. Would love to dive into that bucket. And as you can see with that black rock, looks like broken pieces from some quarry and then machine tumbled to get the sharp edges off and make them smooth. That's why those sticking out edges look lighter in color.. Can look nice at first sight but once submersed this smoothy look will rather pop out and look very unnatural. Rock just doens't weather naturaly like that.

 

[Heagney]

Thanks very much for all the info guys. I do really like a few of the rocks!

 

[Tommytwotens]

At least three of those types of rock will be fine I think... they have slate ( the sharp blueish green one) granite and sandstone there I think which are all aquatic safe. You just want to watch out for any containing limestone as this drastically raises pH. As others have said the acid test will let you know if limestone or not. But I would ask someone in store to show me their slate/ granite. They would know or be able to find out

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[JMorgan]

A tip I picked up from the DIY Joey bloke on you tube - take a knife with you and scratch the rocks. If it skitters off the hardness of the rock compares well to the hardness of steel. A very quick and easy test that eliminates the worst offenders (assuming you don't WANT your water's TDS going up) and then you can drip some HCl acid on the ones you like the look of. I got some acid a few months back cos I'm always trying to help my 11 year old see the practical application of science. We had loads of fun finding different rocks to test . . . carefully obviously!
Quite how teachers manage to make something as inherently interesting as chemistry so dull in the classroom is beyond me . . . apologies to anyone reading this who's an inspiring science teacher!
cheers