Ozone, DOC, GAC

[djf91]

Hi everyone,

I’ve been doing some research on ozone generator use in aquariums and I wanted to get a bit more information on how they work, what they do and don’t do, and how they effect organics when used on our systems.

I’ve heard from some people that they do in fact reduce DOC/organics in our system by oxidizing these compounds out of existence. I’ve also heard that they break down the compounds into smaller pieces that are more easily skimmed out and removed by GAC. I’ve also heard they simply just decolorize the organics but don’t play any part in helping remove them from the system.

I recently submitted an oceamo ICP which came back with high DOC for my system. This may explain some of the cyano issues I have and also some slow STN on some my Acropora colonies. I run GAC now but I don’t think it’s enough and this can become quite costly for a 600 gallon system.

Based off this do you think ozone would be right for my system for what I’m trying to accomplish? Will it help me lower DOC if used with GAC?

Thanks for your help!

 

[Randy Holmes-Farley Verified Community Expert]

I do not consider ozone as particularly effective at reducing organics overall, but it may help. It is very good at reducing the yellowing components in organics without removing the offending organic itself.

I cover all these sorts of questions in these articles:

Ozone and the Reef Aquarium, Part 1: Chemistry and Biochemistry by Randy Holmes-Farley - Reefkeeping.com

Ozone and the Reef Aquarium, Part 2: Equipment and Safety by Randy Holmes-Farley - Reefkeeping.com

Ozone and the Reef Aquarium, Part 3: Changes in a Reef Aquarium upon Initiating Ozone by Randy Holmes-Farley - Reefkeeping.com

from the first one:

In a marine mammal pool, for example, it was found that disinfection with 4 ppm ozone with a 30 minute contact time (a disinfection level much higher than is typically used in reef aquaria) did not reduce the pool's total organic carbon (TOC) (~13 ppm TOC), while the use of granular activated carbon (GAC) did reduce it by 37%. Interestingly, the combination of ozone and GAC was even more effective, removing 60-78% of the TOC, suggesting that the ozonation may have altered some of the molecules in a way that made them bind more strongly (or more rapidly) to GAC. An alternative explanation that cannot be ruled out involves biological transformations of the organic compounds taking place on the GAC surface as it became colonized with bacteria).

 

[mmorrison55]

RHF…

So do you recommend if running ozone to also run GAC?

 

[djf91]

I do not consider ozone as particularly effective at reducing organics overall, but it may help. It is very good at reducing the yellowing components in organics without removing the offending organic itself.

I cover all these sorts of questions in these articles:

Ozone and the Reef Aquarium, Part 1: Chemistry and Biochemistry by Randy Holmes-Farley - Reefkeeping.com

Ozone and the Reef Aquarium, Part 2: Equipment and Safety by Randy Holmes-Farley - Reefkeeping.com

Ozone and the Reef Aquarium, Part 3: Changes in a Reef Aquarium upon Initiating Ozone by Randy Holmes-Farley - Reefkeeping.com

from the first one:

In a marine mammal pool, for example, it was found that disinfection with 4 ppm ozone with a 30 minute contact time (a disinfection level much higher than is typically used in reef aquaria) did not reduce the pool's total organic carbon (TOC) (~13 ppm TOC), while the use of granular activated carbon (GAC) did reduce it by 37%. Interestingly, the combination of ozone and GAC was even more effective, removing 60-78% of the TOC, suggesting that the ozonation may have altered some of the molecules in a way that made them bind more strongly (or more rapidly) to GAC. An alternative explanation that cannot be ruled out involves biological transformations of the organic compounds taking place on the GAC surface as it became colonized with bacteria).

Hi Randy,

Yes I had seen that in another thread you posted in. That is a significant amount of reduction it seems if you use the two methods together. The last sentence in that paragraph though (biological transformation of the organic compounds), is that happening as a result of the ozone use?

 

[Randy Holmes-Farley Verified Community Expert]

RHF…

So do you recommend if running ozone to also run GAC?

Yes. It’s breaks down the residual oxidants from ozone use.

 

[X-37B]

I started my 170 with an Mutiny ozone reactor. I now just run it through my skimmer like I have done in the past. Same results, clear water, with less ozone and not needing 1 liter of carbon in the reactor.
I run 1 cup of rox changed every 2-3 weeks. However this is upstream from my skimmer.
I have turned it off for a few weeks and the only difference was a drop in orp. Nothing visible anyway but the skim was darker with ozone.

 

[Randy Holmes-Farley Verified Community Expert]

Hi Randy,

Yes I had seen that in another thread you posted in. That is a significant amount of reduction it seems if you use the two methods together. The last sentence in that paragraph though (biological transformation of the organic compounds), is that happening as a result of the ozone use?

The possibility is that there were organics that were only slowly metabolized so accumulated, but if they are broken in ways that bacteria can then consume, they may eat the whole organic left. I can think of lots of natural molecules that fit that description, but I cannot be sure how important the process is.

 

[bubbgee]

There is still no concrete evidence for DOC affecting tanks negatively, right? As far as I've read, it's mostly observational and anecdotal.

 

[mmorrison55]

Yes. It’s breaks down the residual oxidants from ozone use.

My bad… I was getting GAC and GFO mixed up in my mind… my mutiny reactor already has GAC on the output that my ozone goes through.

 

[Randy Holmes-Farley Verified Community Expert]

There is still no concrete evidence for DOC affecting tanks negatively, right? As far as I've read, it's mostly observational and anecdotal.

Yellowing is an obvious aesthetic issue.

More folks are becoming concerned about organics, but my issue is that there are vast numbers of different organics with different physical, chemical, and biological properties.

talking about them all as one is like talking about all inorganic elements in seawater as if they were the same.

 

[bubbgee]

Yellowing is an obvious aesthetic issue.

More folks are becoming concerned about organics, but my issue is that there are vast numbers of different organics with different physical, chemical, and biological properties.

talking about them all as one is like talking about all inorganic elements in seawater as if they were the same.

I agree with you on this.

 

[djf91]

There is still no concrete evidence for DOC affecting tanks negatively, right? As far as I've read, it's mostly observational and anecdotal.

I don’t think anything’s concrete and we are still in the infancy of learning the relationships between DOC, bacteria, algae, viruses, coral disease.

Everyone’s system is different with too many variables to account for and also what your goals are for the system. For me I’m trying to run an Acropora dominated reef and it’s my opinion that too high of organics can cause bacterial issues and thus disease. I might be wrong, who knows. Worth playing with though.

 

[djf91]

I started my 170 with an Mutiny ozone reactor. I now just run it through my skimmer like I have done in the past. Same results, clear water, with less ozone and not needing 1 liter of carbon in the reactor.
I run 1 cup of rox changed every 2-3 weeks. However this is upstream from my skimmer.
I have turned it off for a few weeks and the only difference was a drop in orp. Nothing visible anyway but the skim was darker with ozone.

Why less GAC needed? Wouldn’t you burn through more GAC if the ozone is allowing the GAC to extract more organics?

 

[bubbgee]

I don’t think anything’s concrete and we are still in the infancy of learning the relationships between DOC, bacteria, algae, viruses, coral disease.

Everyone’s system is different with too many variables to account for and also what your goals are for the system. For me I’m trying to run an Acropora dominated reef and it’s my opinion that too high of organics can cause bacterial issues and thus disease. I might be wrong, who knows. Worth playing with though.

I watched this one too. I totally respect Julian but it's still anecdotal and observational. The science isn't completely there. I would rather do an aquabiomics test instead of testing for DOC since that can detect vibrio and other bacteria that can cause potential issues down the road.

 

[djf91]

I watched this one too. I totally respect Julian but it's still anecdotal and observational. The science isn't completely there. I would rather do an aquabiomics test instead of testing for DOC since that can detect vibrio and other bacteria that can cause potential issues down the road.

I think the science is anecdotal when applied to our aquariums but the studies they’ve conducted in the ocean on tropical reefs are at least somewhat definitive.

 

[Randy Holmes-Farley Verified Community Expert]

I think the science is anecdotal when applied to our aquariums but the studies they’ve conducted in the ocean on tropical reefs are at least somewhat definitive.

What experiments exactly? The video is over an hour long.

 

[backbayreef]

I'm running an Avast Mutiny 2.0 in a 450gal tank, 24/7 at 30%. I've swapped out the Avast GAC canister with the GEO for easier media replacement. A few observations:
1. Water is crystal clear!
2. ORP bounces between 410 - 425 mV and will be shut down at 450 mV

I can't comment on DOC and disease prevention, I'm doing this for water clarity and love it!

 

[bubbgee]

I'm running an Avast Mutiny 2.0 in a 450gal tank, 24/7 at 30%. I've swapped out the Avast GAC canister with the GEO for easier media replacement. A few observations:
1. Water is crystal clear!
2. ORP bounces between 410 - 425 mV and will be shut down at 450 mV

I can't comment on DOC and disease prevention, I'm doing this for water clarity and love it!

This one I can go with. I learned to just accept my water can't be completely clear (I blame my diamond goby for that lol).

 

[backbayreef]

This one I can go with. I learned to just accept my water can't be completely clear (I blame my diamond goby for that lol).

Guilty until proven innocent, esp gobies! lol

My first time doing Ozone and it’s a day and night difference! I can clearly see across an 8ft tank and beyond.

 

[Randy Holmes-Farley Verified Community Expert]

Guilty until proven innocent, esp gobies! lol

My first time doing Ozone and it’s a day and night difference! I can clearly see across an 8ft tank and beyond.

It is an unquestionable aesthetic effect to the viewer that ozone clears the water.

But is that a benefit to organisms that are filter feeders?