Rock usage in marine tank

[AlexMafi]

Hello I've recently purchased this rock from a garden center and wondered if I could use this for my marine tank. I'm not sure of its structure, could be limestone but could be something else. I think my question is really can I use any type of rock in the marine aquarium ?

Any advice would be great, thanks.

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[Mr tap water]

This is just my opinion but I would say you would be taking a risk as you don't know what sort of chemistry reaction it will take with the salt water.


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[AlexMafi]

Thanks, It just seems a cool rock and would look good in the tank. It's a new tank set up so I don't really have anything in to crash other than the other live rocks in the tank so I may give it a go.

The rock was made for freshwater tropical fish.

[Delapool]

Does look like limestone with the pitting. Have you tried putting any acid on it? If it is more magnesite or dolomite you might need to leave the acid on the rock (eg in a depression or cavity) and check after a bit for any bubbles.

Also check nothing has been sprayed on it I guess. Eg weed killers.

[AlexMafi]

Thanks Delapool, I did think it was limestone and will try the old vinegar test when I have chance to confirm.

The garden center had a fresh water tropical fish section so I suspect it will be clean of any weedkiller. I'm more concerned about the composite of the rock i.e any metals that could contaminate the tank. I am correct in thinking that if it is limestone it will be okay to add to the tank?

[melosu58]

Is there any kind of tag on it that might tell you what the composition is?
If not that one maybe another on the stand.

[Delapool]

I'd need a salty to double check but can't see any problems and should be fairly stable.

What sort of elements are issues for saltwater?

[Mr tap water]

Apparently from what I gather limestone if that's what it is can be used in a marine system They do say there is different varieties some have more heavier metals in them but other than that can be used but would advise to keep an eye out on your PH in the beginning.


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[AlexMafi]

The only think gI have to go on Melosu is on the receipt I have 'Yellow spongy Aquar Rock' which doesn't help.

I'm knew at Marine Delapool but I think copper really bad.

That's great Tap Water, hopefully it's limestone. it seems a good rock to add my corals to

[Delapool]

Originally Posted by AlexMafi

The only think gI have to go on Melosu is on the receipt I have 'Yellow spongy Aquar Rock' which doesn't help.

I'm knew at Marine Delapool but I think copper really bad.

That's great Tap Water, hopefully it's limestone. it seems a good rock to add my corals to

Lol, that is kind of vague. They should all be labelled properly imo (climb off soap box).

If they provide it for cichlid tanks that might help. I don't keep SW at all, so can only really offer thoughts on what the rock might be.

[melosu58]

Limestone would be OK. My problem is any other compounds that might be added. Limestone gives a boost to your alkalinity in your tank.

[Delapool]

If I'm reading correctly (and guessing a lot), the limestone would be OK if just calcite while anything of dolomite would not be so useful (as magnesium isn't used much by saltwater corals?), but the limestone is probably going to be stable at the ph saltwater tanks are kept at(?).

If the limestone has copper, (also wondering on strontium), it might release back into system. So as saltwater tanks seem to require more stability might be better off getting carbonates specifically sold for saltwater tank - guessing again, is that anywhere near correct?

[Marty.h]

Corals do use magnesium I currently dose 210ml of magnesium a day to keep my parameters stable !!! Magnesium is also important to stop precipitation of calcium and alk out of solution.

The risk of elements that could potentially leach from those rocks seems to much of a risk to take in a marine quarium as it's not like loosing say a £5 plant being a cheap one when a cheap coral will set you back £40.

Copper in a reef aquarium is a big no no it will kill your corals and inverts but is fine for FOWLR ( fish only with live rock )

Myself personally would use the correct rock so you know what's going into your tank I keep a full reef myself so speak from experience

[Mr tap water]

Originally Posted by Marty.h

Corals do use magnesium I currently dose 210ml of magnesium a day to keep my parameters stable !!! Magnesium is also important to stop precipitation of calcium and alk out of solution.

The risk of elements that could potentially leach from those rocks seems to much of a risk to take in a marine quarium as it's not like loosing say a £5 plant being a cheap one when a cheap coral will set you back £40.

Copper in a reef aquarium is a big no no it will kill your corals and inverts but is fine for FOWLR ( fish only with live rock )

Myself personally would use the correct rock so you know what's going into your tank I keep a full reef myself so speak from experience

Would totally agree with this


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[AlexMafi]

Thanks for your advice everyone

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[Delapool]

Thanks as well - learnt something new. That is expensive on the coral! (that's about max price I have ever paid for a high-end plant).

[Marty.h]

Originally Posted by Delapool

Thanks as well - learnt something new. That is expensive on the coral! (that's about max price I have ever paid for a high-end plant).

That's for a cheap coral some of mine are over £200 each !! And I would not want to gamble with them.

[Delapool]

Originally Posted by Marty.h

That's for a cheap coral some of mine are over £200 each !! And I would not want to gamble with them.

Ouch! That's a good point.

Out of interest what level of magnesium do you maintain in a saltwater tank?

[Marty.h]

I run mine at 1350