Sps and rox .8 carbon

[Viracon13]

I used Rox .8 in a mesh bag in my sump for a couple years in an SPS tank, never had any issues. Only used about 2/3 the recommended amount

 

[bubbaque]

I actually started using it after I started this thread and started to get stn on the base of some corals, I am not sure why it happens to me. I only used 1/2 cup in a 180 gallons. Flow was pretty high through the media reactor, not sure if that was the issue or maybe it's because I never use carbon and the sudden decrease in DOC shocked the corals. I wish I could figure it out.

 

[Randy Holmes-Farley Verified Community Expert]

Second is contact time. Slower flow allows better contact time and removes more efficiently. Also prevents premature clogging because moving less volume through the filter means it will pick up less particles. Remember carbon and GFO are removing molecules, very tiny things, let the skimmer and filter socks pick up the larger particles they just clog the carbon and prevent it from being the most efficient.

I certainly agree that one needs to be careful when first initiating GAC to reduce the risk of light shock when reducing yellowing.

But I can't agree with the idea that increased contact time is desirable for most efficient use of carbon. Some hobby authors also get this wrong, and maybe that's where it first came from. I argued with one of these folks quite a bit.

It would absolutely be true that increasing contact time would have no effect or would improve the rapidity that GAC binds organic matter from seawater IF it was a one pass system. BUT IT IS NOT, it is a recirculating system.

So lower contact time just means you are bringing in dirty (dirtier) water faster. The actual "contact time" of the GAC with the water is 100% of the time. It is always in contact with aquarium water.

The thing that then becomes a factor is the concentration of organics in the water. The more organics in the water, the faster the GAC will bind them. The faster you replace the clean water near the GAC with dirty water from the aquarium, the more organics will be bound over time. Faster flow also reduces the "dead zone" at the surface of the GAC, thorough which organics must diffuse as opposed to be carried by flow.

Of course, there are limitations to this analysis. You do not want flow so high that there are undesirable things happening, such as the GAC getting beaten to bits, channeling through the carbon, air or debris getting into the GAC bed and clogging it faster, etc. The flow analysis also suggests there is a plateau effect, when the incoming dirty water is only very slightly more dirty than the water leaving the GAC, at which point, higher flow doesn't improve binding rates.

 

[bif24701]

I certainly agree that one needs to be careful when first initiating GAC to reduce the risk of light shock when reducing yellowing.

But I can't agree with the idea that increased contact time is desirable for most efficient use of carbon. Some hobby authors also get this wrong, and maybe that's where it first came from. I argued with one of these folks quite a bit.

It would absolutely be true that increasing contact time would have no effect or would improve the rapidity that GAC binds organic matter from seawater IF it was a one pass system. BUT IT IS NOT, it is a recirculating system.

So lower contact time just means you are bringing in dirty (dirtier) water faster. The actual "contact time" of the GAC with the water is 100% of the time. It is always in contact with aquarium water.

The thing that then becomes a factor is the concentration of organics in the water. The more organics in the water, the faster the GAC will bind them. The faster you replace the clean water near the GAC with dirty water from the aquarium, the more organics will be bound over time. Faster flow also reduces the "dead zone" at the surface of the GAC, thorough which organics must diffuse as opposed to be carried by flow.

Of course, there are limitations to this analysis. You do not want flow so high that there are undesirable things happening, such as the GAC getting beaten to bits, channeling through the carbon, air or debris getting into the GAC bed and clogging it faster, etc. The flow analysis also suggests there is a plateau effect, when the incoming dirty water is only very slightly more dirty than the water leaving the GAC, at which point, higher flow doesn't improve binding rates.

Ok, this makes good sense. Since it is a recirculating system contact time is not relevant, more flow increases organic concentration and bind rates with the GAC.

Thanks Randy!

 

[bubbaque]

@Randy Holmes-Farley the little bit of stn I am getting since adding the rox carbon is probably from light shock? Would you recemmend leaving the carbon in and just riding it out or remove it?

 

[Randy Holmes-Farley Verified Community Expert]

If it is light shock, its hard to know if it is too late to help or not. Screening might help, or shock them the other way. You might ask Dana Riddle if he has an idea how to proceed.

I personally might try a bit of screening of some sort.

 

[Randy Holmes-Farley Verified Community Expert]

Ok, this makes good sense. Since it is a recirculating system contact time is not relevant, more flow increases organic concentration and bind rates with the GAC.

Thanks Randy!

Happy Reefing.

 

[bubbaque]

@Randy Holmes-Farley I guess what I'm asking is there any other negative effects carbon can generally cause besides sudden light shock from the clarity. I generally only hear great things about carbon.

 

[Randy Holmes-Farley Verified Community Expert]

@Randy Holmes-Farley I guess what I'm asking is there any other negative effects carbon can generally cause besides sudden light shock from the clarity. I generally only hear great things about carbon.

Some types may contribute to HLLE (dusty, non acid washed types; ROX 0.8 is acid washed).

You could possibly drop trace elements too low by binding those that are bound to organics, but I don't know to what extent that happens in reality.

Some organisms feed on organics in the water, but again, I don't know to what extent that happens in reality in amounts to be undesirable instead of desirable.

 

[Salty1962]

I've never heard of carbon causing RTN. I use .08 in a reactor that I replace every month to keep my eater clear.

 

[bubbaque]

I didn't get any rtn, I got what looked like tip burn.

 

[OnPointCorals Verified Sponsor]

Any followup to this post? I started running rox.08 and now two weeks later am experiencing burnt tips with algae growth on them, Along with several RTN. Nothing else has been changed in the last 3 months. Lost my big Cali tort colony that has been growing at the top of the tank for 2 years. (I didn't think anything could kill that).

SPS dominated tank, with many colonies and frags. Tank has been up and running successfully for 4 years. (140 gallon total water volume) Previoulsy ran bituminous carbon 2 cups in a reactor 24/7, changed out monthly. I ran the ROX 1 cup for the last 2 weeks.

 

[XNavyDiver]

what are your thoughts on using this carbon with sps? I tied to use it about a year ago in a media reactor at half the recommended amount and after using it I got some some stn a couple of days later. I am wanting to use it again but am scared to use it.

If your using have you ever ran into problems?

I run about 2 cups in a brs reactor and everything's good in my tank....so far.

 

[XNavyDiver]

Any followup to this post? I started running rox.08 and now two weeks later am experiencing burnt tips with algae growth on them, Along with several RTN. Nothing else has been changed in the last 3 months. Lost my big Cali tort colony that has been growing at the top of the tank for 2 years. (I didn't think anything could kill that).

SPS dominated tank, with many colonies and frags. Tank has been up and running successfully for 4 years. (140 gallon total water volume) Previoulsy ran bituminous carbon 2 cups in a reactor 24/7, changed out monthly. I ran the ROX 1 cup for the last 2 weeks.

You might want to dial down the intensity of your lights and/or let your alk come down.

 

[hybridazn]

Any followup to this post? I started running rox.08 and now two weeks later am experiencing burnt tips with algae growth on them, Along with several RTN. Nothing else has been changed in the last 3 months. Lost my big Cali tort colony that has been growing at the top of the tank for 2 years. (I didn't think anything could kill that).

SPS dominated tank, with many colonies and frags. Tank has been up and running successfully for 4 years. (140 gallon total water volume) Previoulsy ran bituminous carbon 2 cups in a reactor 24/7, changed out monthly. I ran the ROX 1 cup for the last 2 weeks.

I run 3/4 cup in my system that is roughly 200 total gallons. Rox is potent stuff

 

[bubbaque]

Any followup to this post? I started running rox.08 and now two weeks later am experiencing burnt tips with algae growth on them, Along with several RTN. Nothing else has been changed in the last 3 months. Lost my big Cali tort colony that has been growing at the top of the tank for 2 years. (I didn't think anything could kill that).

SPS dominated tank, with many colonies and frags. Tank has been up and running successfully for 4 years. (140 gallon total water volume) Previoulsy ran bituminous carbon 2 cups in a reactor 24/7, changed out monthly. I ran the ROX 1 cup for the last 2 weeks.

Not to much to update. I removed the rox, did a large water change to get back in whatever it possibly took out. The stn stopped and all went back to normal. I use the larger stuff now when I use carbon as I am scared to run ROX now.

 

[Scorpius]

Run rox at half the amount you need. Same goes for high capacity gfo or any gfo for that matter.

 

[OnPointCorals Verified Sponsor]

Run rox at half the amount you need. Same goes for high capacity gfo or any gfo for that matter.

Yup. That’s where I went wrong. Started with way too much ROX in reactor. Took offline yesterday still finding victims. Big Plana Colony 50% of tips burnt. Sucks. I’m too scared to use ROX again.

 

[Rakie]

Never had an issue. You could potentially strip too much... But really, I've never seen a direct problem with rox carbon. Unless maybe you didn't wash it nearly enough, that may cause issue.

 

[bubbaque]

When I had issues I ran about 1/2 cup in 180 gallons. I'm not sure if the issue came from never running carbon to first running rox but I definitely had an issue with it. I just stay away from it now because I'm worried about running into issues. When I was searchingly the internet when I had issues I found a video of leng si had stn and rtn in his tank when he used the rox also.

I know MANY people use it and have no issues what so ever but I just stick with the larger carbon now but I rarely ever use it.