Using TOO much carbon causes GHA?

[mpderksen]

A quick search on carbon amounts let me to an article that using too much can leech phosphate into a tank, leading to GHA. Guilty of "more is better" I have been using a full cup of ROX BRS carbon in my dual reactor with a matching cup of GFO.
Too much?

Michael

[asudavew]

A quick search on carbon amounts let me to an article that using too much can leech phosphate into a tank, leading to GHA. Guilty of "more is better" I have been using a full cup of ROX BRS carbon in my dual reactor with a matching cup of GFO.
Too much?

Michael

Depends on the volume of your setup.

[Pife]

Depends on the nutrient levels in your tank.

[asudavew]

BRS GFO/Carbon Calculator (http://www.bulkreefsupply.com/reef-calculator)

[wrott]

Algae is not a real issue, it's good to have some--looks bad to have too much.
Eventually, even if carbon adds PO4 it will balance out and algae will die off. I don't think carbon will cause algae, but it's definitely possible. Take the carbon off-line for a few months and see if there's a difference.

[DDon]

Here's an interesting article comparing different phosphate sources in aquariums and puts the potential contribution of leaching by GAC into perspective.

http://www.advancedaquarist.com/2012/3/chemistry

[Wonton Soup]

Granulated active carbon is created in at least a couple of different ways. A single gram of GAC has roughly the surface area of an entire tennis court. It's hard to imagine because your eye cannot see but GAC is extremely porous at the microscopic level.
GAC is given this vast amount of microscopic surface area by being etched with acid(s).

The cheapest and most typical acid used to etch carbon is phosphoric acid. It works very well. However, it is not always properly rinsed after being etched and can therefore become a source of leached phosphates when used in the aquarium.

Hydrochloric acid is also used to etch carbon but usually costs more than phosphoric acid and is less likely to have been used.

Unfortunately, manufacturers don't post this on their labels. Either type is safe to use in an aquarium and even the residual phosphoric acid used in cheaper GACs can mostly be rinsed off before being placed in the aquarium.

I hope this helps!

[AcroporAddict]

I would not put any stock into thinking too much GAC or any amount of GAC contributes in any way, shape or form to GHA growth.

[ColtonMeng]

My guess is that most companies manufacturing GAC are using a strong base like KOH 45% as their reactant. Price wise, it's about 80% the price of good phos 75 in full bulk on an active basis. (non NaChurs phos, which has higher levels of arsenic)

No clue about the efficacy of using a strong base versus a strong acid for activation, so it's definitely possible I'm off.

-C

PS - HCl is significantly lower in cost than phosphoric acid. Along the lines of $0.25 / lb. at 28% versus ~$0.65 / lb. at 75%, depending on quality of phosphoric acid. Also note that phosphoric is considered a "weak" acid. Only reason to use it over HCl would be from a handling standpoint - trying to react a large quantity of GAC in a vessel containing HCl would create quite the cloud- particularly nasty to work with.

[ColtonMeng]

I would not put any stock into thinking too much GAC or any amount of GAC contributes in any way, shape or form to GHA growth.

I second this.

[mpderksen]

Okay. Just double checking. Learned a lot from the article linked above. Thanks.