Aragocrete

[friendlyAlien]

Hi,

I have some Aragocrete from the one and only source in my tank and have been very happy with it until last month. It is about 2 years old ...

Now all of sudden pieces break loose and when I touch it literally falls apart when touching it.

It also seems to affect the water parameters ...

Has anyone heard of this before?

Cheers,
Carsten

 

[dalbrecht]

what was the original recipe ( if known), also what is your aquariums pH?

Concrete will degrade over time in certain circumstances, My first thought would be a sudden change in pH causing disolution of structural elements.

 

[friendlyAlien]

PH is 8.2 and the recipe is only known to the makers (I didn't make it myself but bought it from Garf.

 

[SkiFletch]

Sounds like the concrete is breaking down and you may be leaching silicates into the water.

 

[friendlyAlien]

So ... what is the right thing to do then - remove it all? (argl)

 

[dalbrecht]

I wouldn't worry about removing all of it. Garf grunge is primarilly made from crushed coral/ aragonite & portland cement. The cement contains silicon, sulfur & calcium compounds.

I would try to ensure that your phosphate levels are as low as possible to prevent a diatom bloom, I would maintain aeration as well.

What is your coraline / organism coverage of the rock?

What is your night ph? are you dosing calcium?

 

[friendlyAlien]

The PH at night drops to 8 and sometimes (very rarely to 7.8). The coraline is great - it covers the rock but stopped spreading in the last two months (since the aragocrete falls apart).

I test for calcium and alk and calcium is stable between 380 and 450 while I have always had trouble with alk ... it goes between 5 and 8.

All tests are Salifert approved

And yes, I am dosing ...

 

[friendlyAlien]

(p.s.: Yes I had a diatom bloom but a massive water change fixed that and it has been stable for two weeks now. Said that I always had a diatom bloom in the spring ....)

 

[dalbrecht]

If your rock stack is still stable I would leave it in there. You may want to replace a few pieces from time to time but as long as it is stable I don't see it hurting anything. I would focus on dosing extra dkh insead of an absolute 2 part, it strikes me that you are using Carbonate faster than calcium.

I really don't think it will hurt anything to leave the rock in (unless it has a high risk of avalanche)