Dry Macro rock - does it leach phosphate or silicate?

[danreef55]

I have built this aqua scape for my new build out of Macro dry rock.

Will definitely be rinsing with RODI but do I need to cook it? Has anyone had problems with leaching from dry Marco rock?
Appreciate any guidance.

 

[bakbay]

That’s one awesome aquascape! Please come over and do mine when you’re free?

I’ve used dry rocks (and got some Marco rocks) before and the ugly phase is inevitable. My cube was all dry rocks and BB so that was rough for several months. My other tank started with half dry rocks, live rocks (from other tank), and sand. It was very easy to cycle and pristine clean today after a year - no nuisance algae!

You will have PO4 leaching later but with good husbandry and nutrient exports, it should be fine. “Cooking” rocks means just cycling them in salt water with a pump and no lights, right? I just cycle mine in the tank!

 

[GSPClown94]

My experience with dry Marco rock has been little to no phosphate bound in the rock. Others have had a different experience with elevated phosphate. Only one way to find out, get them wet and test for phosphate in the water then adjust as needed.

 

[danreef55]

That’s one awesome aquascape! Please come over and do mine when you’re free?

I’ve used dry rocks (and got some Marco rocks) before and the ugly phase is inevitable. My cube was all dry rocks and BB so that was rough for several months. My other tank started with half dry rocks, live rocks (from other tank), and sand. It was very easy to cycle and pristine clean today after a year - no nuisance algae!

You will have PO4 leaching later but with good husbandry and nutrient exports, it should be fine. “Cooking” rocks means just cycling them in salt water with a pump and no lights, right? I just cycle mine in the tank!

Glad you like the scape. Thank you.
Cook is the wrong term I guess

My experience with dry Marco rock has been little to no phosphate bound in the rock. Others have had a different experience with elevated phosphate. Only one way to find out, get them wet and test for phosphate in the water then adjust as needed.

Put a piece of rock in 1/2 gal of ro water and have it sitting on my desk for the past 3 days. Tested it this morning and no trace. I will keep it there for a month and check again.

 

[Randy Holmes-Farley Verified Community Expert]

Glad you like the scape. Thank you.
Cook is the wrong term I guess

Put a piece of rock in 1/2 gal of ro water and have it sitting on my desk for the past 3 days. Tested it this morning and no trace. I will keep it there for a month and check again.

Might desorb better into salt water, but it probably means there’s not enough to worry about.

 

[danreef55]

Thanks Randy! I will mix up some salt h2o and wait.

 

[Jasongtr]

I've 75lbs of marco rock in my tank, 18 months on I'm dosing phosphates, nothing to worry about

 

[merkmerk73]

They’re made of calcium carbonate just like caribesea life rock

Functionally it’s the same stuff

And you’ll likely have zero phosphates for a while before it leaches back out into the water and then you’ll fight to keep below .1 for a while

I like the product personally

 

[twentyleagues]

I have never had issues with Marco rocks adding anything to the aquarium if its new. Taking phos out of the water maybe. Adding back at a later date tbd.

 

[Reefahholic]

Will usually bind phosphate.

 

[Reefahholic]

Glad you like the scape. Thank you.
Cook is the wrong term I guess

Put a piece of rock in 1/2 gal of ro water and have it sitting on my desk for the past 3 days. Tested it this morning and no trace. I will keep it there for a month and check again.

It’s not gonna leach. I’ve had 6 plus Marco rock tanks. If anything they typically bind the PO4. IMO, it’s very difficult start with Marco. Hard to get it going. Takes almost double the time. You’ll do yourself a huge favor adding 10lbs of LR to it, but also keeping nutrients higher for the first 6 months. Sometimes it won’t grow coralline alage for up to 14 months.

 

[Reefahholic]

They’re made of calcium carbonate just like caribesea life rock

Functionally it’s the same stuff

And you’ll likely have zero phosphates for a while before it leaches back out into the water and then you’ll fight to keep below .1 for a while

I like the product personally

It’s different than any other rock. It’s Florida quarried limestone that’s underground.

The only thing good about it is that it scapes amazingly. The shelf pieces are beautiful.
That’s it.

Otherwise it’s one of the most difficult dry rock options to start a tank with.

 

[Reefahholic]

I've 75lbs of marco rock in my tank, 18 months on I'm dosing phosphates, nothing to worry about

Sounds exactly right. Most people need to dose phosphate.

 

[merkmerk73]

It’s different than any other rock. It’s Florida quarried limestone that’s underground.

The only thing good about it is that it scapes amazingly. The shelf pieces are beautiful.
That’s it.

Otherwise it’s one of the most difficult dry rock options to start a tank with.

Which product specifically is the quarried limestone stuff?

Their coraline rock is calcium carbonate and is listed as such on their website - so is their shelf rock

MarcoRocks Premium Shelf Rock - Natural or Coralline

marcorocks.com

 

[IceNein]

Limestone is predominantly calcium carbonate. I could be off base here, but I believe that their "coralline" rock is just the same quarried rock that has been painted with some sort of reef safe pigment.

Limestone: Characteristics, Uses And Problem

This procedure includes general information on the characteristics and common uses of limestone and identifies typical problems associated with the material. See also 04400-01-S for guidance on inspecting stone masonry failures.

www.gsa.gov

 

[merkmerk73]

You're right - we're just saying the same thing.

In essence the marco rocks and caribsea life rock are just limestone aka calcium carbonate.

 

[twentyleagues]

You're right - we're just saying the same thing.

In essence the marco rocks and caribsea life rock are just limestone aka calcium carbonate.

Liferock is not actually 100% limestone its man made agracrete. Does it contain pieces of limestone/quarried calcium carbonate rock probably but the majority is concrete. Break a piece of Marco rock whats inside? More white rock. Order a box of liferock and open it up, take out one of the many broken arches. Whats inside? Grey concrete and bits and pieces of calcium carbonate.

 

[Johnd651]

Liferock is not actually 100% limestone its man made agracrete. Does it contain pieces of limestone/quarried calcium carbonate rock probably but the majority is concrete. Break a piece of Marco rock whats inside? More white rock. Order a box of liferock and open it up, take out one of the many broken arches. Whats inside? Grey concrete and bits and pieces of calcium carbonate.

I have life rock and it was all white inside.

 

[Reef.]

It’s different than any other rock. It’s Florida quarried limestone that’s underground.

The only thing good about it is that it scapes amazingly. The shelf pieces are beautiful.
That’s it.

Otherwise it’s one of the most difficult dry rock options to start a tank with.

I agree…Not sure if it leaches po4 as much as it soaks it up like a sponge, either way I had a nightmare with it, started a new tank with it and after a few months it was literally green, swapped to Real Reef Rock and no issues, tho I do hear some have no issues with marco rock at all. I would keep a close eye on it and if it starts to give issues slowly change over to something else.

 

[Reefahholic]

I’m

Liferock is not actually 100% limestone its man made agracrete. Does it contain pieces of limestone/quarried calcium carbonate rock probably but the majority is concrete. Break a piece of Marco rock whats inside? More white rock. Order a box of liferock and open it up, take out one of the many broken arches. Whats inside? Grey concrete and bits and pieces of calcium carbonate.

Yep different rock and very difficult to get going for sure.