What Kind Of Rock

[ECCO_]

What kind of rock is this and would it be ok to use in a tank?

 

[Jules H-T]

That doesn't look like rock to me, that looks like some sort of man made concrete bonded hardcore type stuff. It looks likely to contain cement. I would not put that in a fish tank, personally speaking.

Try and find some slate somewhere- you got any slate merchants/users nearby (roofing or fireplaces or kitchen work surface manufacturers)? Find somewhere like that in your local area, pop in, and if you ask nicely they may give you some offcuts for free- just don't accept/put any marble in your tank.

 

[evilchild]

or porus rock that can effect your ph levels

 

[ECCO_]

That doesn't look like rock to me, that looks like some sort of man made concrete bonded hardcore type stuff. It looks likely to contain cement. I would not put that in a fish tank, personally speaking.

Try and find some slate somewhere- you got any slate merchants/users nearby (roofing or fireplaces or kitchen work surface manufacturers)? Find somewhere like that in your local area, pop in, and if you ask nicely they may give you some offcuts for free- just don't accept/put any marble in your tank.

Why not use?
Its not healthy for the fish or because it looks unatural?

 

[chr15_8]

That doesn't look like rock to me, that looks like some sort of man made concrete bonded hardcore type stuff. It looks likely to contain cement. I would not put that in a fish tank, personally speaking.

Try and find some slate somewhere- you got any slate merchants/users nearby (roofing or fireplaces or kitchen work surface manufacturers)? Find somewhere like that in your local area, pop in, and if you ask nicely they may give you some offcuts for free- just don't accept/put any marble in your tank.

Why not use?
Its not healthy for the fish or because it looks unatural?

because if its concrete it will contain lime and other nasty chemicals whuch could kill your fish

 

[ECCO_]

That doesn't look like rock to me, that looks like some sort of man made concrete bonded hardcore type stuff. It looks likely to contain cement. I would not put that in a fish tank, personally speaking.

Try and find some slate somewhere- you got any slate merchants/users nearby (roofing or fireplaces or kitchen work surface manufacturers)? Find somewhere like that in your local area, pop in, and if you ask nicely they may give you some offcuts for free- just don't accept/put any marble in your tank.

Why not use?
Its not healthy for the fish or because it looks unatural?

because if its concrete it will contain lime and other nasty chemicals whuch could kill your fish

Oh, thank goodness for this forum.
I feel better knowing not to use them.

 

[ECCO_]

Another thing, If the rocks I have are harmful because of the concrete, I have seen and heared about people using bricks and stuff in theyre tank. So whats the difference?

 

[Jules H-T]

Cement is that nasty that you need to wear gloves and a mask when mixing it. It is an irritant and as I understand it, carcinogenic.

How that relates to bricks I do not know. Bricks may not even contain cement.

My policy is this: Unless is it entirely inert natural rock, it doesn't go in my tank.

Ps. For the record, whether a rock alters the tank's pH is nothing whatsoever to do with whether it is porous or not. Porous simply means that it is permeable to water (usually through lots of little bubbles of air- kind of like Aero chocolate). It may well be that some porous rocks do alter pH, but saying they all do is like saying red cars can do 150MPH just because you once saw a red car going 150mph.

 

[celaeno]

so the acid test fails (bubbles form) for both ph-raising rocks AND porous rocks? how then do i know if i have a porous rock that doesn't raise the ph? do porous rocks alter the water chemistry regardless of whether or not they raise the ph?

 

[Jules H-T]

I'm not entirely sure I understand the question. Pourous simply refers to the structure of the rock (i.e. it has pores, or holes). The fact that a rock is porous alters the water chemistry in no way at all, any more than a rock being round, square, or carved into the shape of the Venus De Milo would do.

A sponge, or an Aero bar are porous, and will not alter water chemistry, and you can buy lava rock type stuff specifically permitted for use in the aquarium that is very very porous indeed

Some rocks bubble when you put an acid on them. This is because of what they are made of. These rocks can alter your water chemistry.

So you've got two features of a rock- it's physical structure and it's chemical make up. You can have porous and non-porous (physical) and inert or reactive (chemical). You can have any combination of the two (so, porous reactive/non porous reactive/porous inert,/non porous inert). Now there may even be a correlation (i.e. porous rocks tend to be made out of materials that are chemically reactive), but that is not cause and effect. Just because most Ferraris are red, does not mean most red cars are Ferraris.

Porous rocks let bubbles out when submerged (in either water or acid, I guess) because they have air in their pores. Rocks with acid on them release bubbles because of the chemical reaction with the acid creating a gas (and this is an indication that there will be slower reactions in water, and that it is not an inert- or unreactive if you like- rock, and will alter water chemistry). Just because they both bubble when submerged does not mean it is for the same reason.

So, to summarise, it is absolutely incorrect to suggest that porous rocks will alter water chemistry because they are porous. They may well do, but that is purely coincidence.

 

[San O Fisher]

What kind of rock is this and would it be ok to use in a tank?

what you are looking at is a piece of concrete with the top coat ("cream") worn off. That is a chunk of concrete aggregate.

Another good reason not to use it is that since concrete takes so much abuse by running water and whatever else goes down someone's driveway it tends to have a lot of chemicals already bonded in it. These can be trapped in the pours of the concrete and will probably not get out with a basic cleaning.

 

[celaeno]

i performed the acid test on a piece of porous pagoda stone and bubbles formed. how then do i know whether there were bubbles because it's porous, or if it will also raise the ph?

 

[Jules H-T]

You put a piece of the porous rock under normal water and see if you get as much bubbling. If not, then it tells you that the bubbles from the acid were due to a chemical reaction and you don't use the rock. The fact that it is porous means nothing- you tested a rock using the acid test and it failed- end of story. You cannot deduce that the next porous rock will also fail.

 

[andywg]

Cement is that nasty that you need to wear gloves and a mask when mixing it. It is an irritant and as I understand it, carcinogenic.

And cement is so horrendous that it is used as a major ingredient when making DIY Live Rock. I have about 10kg of cement powder in my reef and there are no issues.

The important thing with cement is to cure it in water. Ideally put it in the cistern of a toilet for a few weeks, eventually it will have little to no effect on the pH and then you can throw it in. While curing it can, and will, send the pH past 9.

 

[Jules H-T]

Cement is that nasty that you need to wear gloves and a mask when mixing it. It is an irritant and as I understand it, carcinogenic.

And cement is so horrendous that it is used as a major ingredient when making DIY Live Rock. I have about 10kg of cement powder in my reef and there are no issues.

The important thing with cement is to cure it in water. Ideally put it in the cistern of a toilet for a few weeks, eventually it will have little to no effect on the pH and then you can throw it in. While curing it can, and will, send the pH past 9.

Well fair enough, thank you for clarifying.