Running Activated Carbon 24/7

[Fringe09]

Hi fellow reefers.

6 month old 200 gallon mix reef tank. Major diatom and hair algae which 75-80% has gone away since doing the following about month ago.

• Changed feeding to once a day.
• Started Rowaphos in a reactor.
• Added Activated Carbon (Red Sea REEF-SPEC) in one of the filter socks.
• Stopped Phyto.
• Stopped Red Sea Reefer Energy A and B.
• Hydrogen peroxide for 8 days.

I'm wondering what I should stop, what I should continue doing, and what I can re-start.

Should I continue running Activated Carbon 24/7? Any negative effects?

 

[tsav87]

I wouldn't run GAC more than required, it absorbs iodine, which your corals need. I run it for a few days every other month to help polish the water and remove any unknown contaminants.

 

[HB AL]

I have a bag of carbon in my sump 24/7, don't see any negative effects.

 

[Randy Holmes-Farley Verified Community Expert]

I don't think there's any downside to running GAC 254/7 if it is adequately clean (acid washed types).

 

[Randy Holmes-Farley Verified Community Expert]

I wouldn't run GAC more than required, it absorbs iodine, which your corals need. I run it for a few days every other month to help polish the water and remove any unknown contaminants.

Do you have any evidence that GAC binds significant iodide or iodate from seawater? It seems quite unlikely to me.

I also do not consider iodide useful, but that's a different point to whether GAC binds it.

 

[Jonty]

It seems like you have a winning formula why change?

 

[Fringe09]

It seems like you have a winning formula why change?

No doubt that the diatom and hair algae are almost gone.

I've learning something being new to this hobby. Some things you do until X happens then you evaluate and continue with X or do Y. That's why I posed the question regarding Carbon. Googling it ends up with two distinct points of view.

I'm sure I'll have to evaluate all the other things I've started or stopped. For example, I hear great things about Red Sea Reef Energy A and B. I'm not sure if I start it again, my algae will come back. Maybe with the Rowaphos reactor running, it won't.

 

[ksfulk]

There are numerous techniques or methods that suggest running GAC constantly, and changing every month. As long as the carbon is of high quality and rinsed of fine particulate before use, there shouldnt be any real issues with running it constantly. I run a 1/2 cup of Rox 0.8 carbon in a bag in my sump for the past 18 months (changed monthly) and I dont notice any issues directly attributable to the carbon.

 

[Reef Jeff]

I run GAC 24/7 and it has had no negative impact on my corals that I have ever noticed...if anything, it improves water quality/clarity and they open up more.

I know this thread is not about Iodine/Iodate/Iodide, but I wanted to mention this as I find it very interesting. I always thought GAC removed Iodine/Iodate/Iodide because I was using the Seachem Iodine/Iodide test for years and it always showed undetectable (0 ppm). I switched to the Red Sea test and compared side by side. Seachem always shows zero when the Red Sea test always shows a measurable amount, typically .03 to .06 ppm. I dose potassium Iodide lightly and only when my test shows below .06 ppm. When I used Seachem testing I am certain I was overdosing. Oddly, if you test freshly mixed Salinity Salt by Seachem with the Seachem Iodine/Iodide test you get .06 ppm. If you test that same saltmix with Red Sea Iodine Test, you get .06 ppm. As soon as I add that same saltmix to my tank, wait 30 minutes and retest, it drops to undetectable on the Seachem test and remains at .06 ppm on the Red Sea test. Red Sea claims they test all forms: Iodine/Iodate/Iodide. Seachem calls their's an Iodine/Iodide test. Maybe theirs does not test for Iodate? I don't know. I'm no chemist, but apparently Red Sea's Iodine test is picking up something that Seachem's is not, and whatever Seachem is putting in their salt is changing form as soon as it hits my tank so their test kit can no longer test for it. My main observation is this: I test for Iodine components with Red Sea Iodine test. Last time I changed my GAC it was at .06 ppm. I added new GAC (1 cup per 100 gallons). Next day my Iodine/Iodate/Iodide test showed .06 ppm. I'm also sure the test works. If I do not dose for a week or so, it drops down to about .03. It does that whether I run GAC or not. I tried a test by removing the GAC and got the same result.

I suspect Randy might be better able to explain this oddity.