How often do you change Granular Activated Carbon (GAC)?

[Randy Holmes-Farley Verified Community Expert]

I use DIY coral snow when I do a water change!

That process is very appealing in some ways, but I have a nagging worry about the particles possibly being an issue for filter feeders like sponges. I have no evidence except the simplistic worry of the particles getting into and clogging up fine orifices that filter out edible organics.

 

[kdx7214]

Buy it in bulk. I buy the 5g bucket from BRS.

Do you have a link for that? I'm trying to find it on their site without any luck. Thanks!

 

[rishma]

That process is very appealing in some ways, but I have a nagging worry about the particles possibly being an issue for filter feeders like sponges. I have no evidence except the simplistic worry of the particles getting into and clogging up fine orifices that filter out edible organics.

even though I started with actual live rock, I don’t think I have much sponge growth so I cannot say. I’ve been using the coral snow for a year or so.

 

[Reefglide]

Do you do anything to limit the yellowing of the water due to organics?

Have never noticed any significant yellowing. My belief is that the Refugium is taking care of it. I run it 8 hours per night opposite display light cycle. Pretty heavy bio load. Feed once a day. I’ve tried different foods and additives to raise Trates and phos but without success. Currently phosphates are undetectable and nitrates around .04. Also believe the corals are taking up a significant amount of nutrients.

 

[X-37B]

Do you have a link for that? I'm trying to find it on their site without any luck. Thanks!

Here's a screen shot of it.

 

[kdx7214]

Here's a screen shot of it.

Thanks, I'll try searching for bulk bituminous :)

 

[Pod_01]

Have known several reefers over the years that had epic crashes due to carbon leaching contaminates.

@Randy Holmes-Farley , just a quick question. Can GAC do what is stated above?

The reason I ask is that I keep reading about GAC crashing reef systems due to leaching but I am just not understanding how this works.

I can understand if reefers use too much GAC and shock the system.

I can also understand GAC describing when it reaches equilibrium with water column…

 

[Randy Holmes-Farley Verified Community Expert]

Have never noticed any significant yellowing. My belief is that the Refugium is taking care of it. I run it 8 hours per night opposite display light cycle. Pretty heavy bio load. Feed once a day. I’ve tried different foods and additives to raise Trates and phos but without success. Currently phosphates are undetectable and nitrates around .04. Also believe the corals are taking up a significant amount of nutrients.

Ok, but most folks do get yellowing without something to export organics. Even with skimming and GAC, ozone made my water visibly less yellow.

 

[Daz_1978]

@Randy Holmes-Farley , just a quick question. Can GAC do what is stated above?

The reason I ask is that I keep reading about GAC crashing reef systems due to leaching but I am just not understanding how this works.

I can understand if reefers use too much GAC and shock the system.

I can also understand GAC describing when it reaches equilibrium with water column…

"The reasons given for not using carbon or not using it continuously include: the carbon causes some diseases, it removes beneficial elements/substances for the water, and eventually the carbon will de-adsorb everything killing the tank inhabitants. None of these reasons have ever been supported by experiments or tests. Rather, they are myths. And as myths, they circulate through the hobby growing a life of their own which becomes hard to kill." ~ Timothy A. Hovanec, Ph.D.

 

[Randy Holmes-Farley Verified Community Expert]

@Randy Holmes-Farley , just a quick question. Can GAC do what is stated above?

The reason I ask is that I keep reading about GAC crashing reef systems due to leaching but I am just not understanding how this works.

I can understand if reefers use too much GAC and shock the system.

I can also understand GAC describing when it reaches equilibrium with water column…

I've never seen a first hand account of such a thing, and am not sure what it even means. Are we talking about a low quality GAC that needs rinsing and wasn't? A decent GAC that was somehow contaminated with something that came back off when someone reused it?

In any case, I see zero reason to be concerned that a high quality GAC like ROX 0.8 will cause problems by releasing problematic levels of anything.

 

[rishma]

Friendly tip, I think people should rinse even rox 0.8. I rarely run carbon so I forgot about rinsing and last time I used it my corals were really unhappy for days. i assume it was due to fines. Even if I wrong, a quick RO/DI rinse cannot hurt.

 

[Randy Holmes-Farley Verified Community Expert]

Friendly tip, I think people should rinse even rox 0.8. I rarely run carbon so I forgot about rinsing and last time I used it my corals were really unhappy for days. i assume it was due to fines. Even if I wrong, a quick RO/DI rinse cannot hurt.

That's certainly reasonable. :)

 

[Jan86]

So out of curiosity, why 1/2 every 2 weeks?

I change all every 4 weeks, no particular reason. It was stated on one of the brands I used…

I do the same just for more stability. Better would be 1/4 every week but it could be just too much work . Half every 2 weeks works very nice imo