GFO vs. Carbon Dosing

[Dwb859]

Is carbon dosing a better means for maintaining low phosphate levels than gfo? I currently have macro algae and use gfo. Just seems like bacteria consuming this and being skimmed out would be more efficent than media that absorbs. Thinking about going the carbon / bacteria route and would like to hear some peoples input.

Is is counter productive to run gfo along with a carbon dosing?

 

[Dwb859]

I have a 150 gallon tank and the refugium section of my sump is only about 10 gallons or so, can that little bit of macro algae (calerpa) be that effective at removing nutrients?

 

[Steve Wright2]

hi Dwb859

a bump for you in addition to an answer
and a suggestion that this question would be better posted in the Chemistry forum

I have been carbon dosing for approx 2 years
my reef tank now has very little algae of any type

I still need to use GFO, and my main reason for that is , when I have decided not to use it, I have noticed my glass gets dirtier much sooner, than it does when I am running it
thus irrespective of the test kit results the speed at which the micro algae builds up, is telling my I have nutrients which the carbon dosing alone is not processing

in many cases limited Nitrate becomes a factor towards the inability of the bacteria removal of phosphates (there is a ratio and if the N has gone there may be some residual P)
and for those people, of which I believe I am one, running GFO in addition to carbon dosing has given me an advantage

Steve

 

[swcc]

carbon dosing tends to become nitrate limited thus phosphate isleft behind. gfo is better at removing phosphate from the water column.

 

[downbeach]

I was using both/either/or vinegar and vodka with some success, while running GFO. I opted to go with a solid carbon (bio-pellets) and removed the GFO to see the results. Although the pellets were able to get my NO3 to negligible levels, I wasn't able to get my PO4 below .08 (Hanna meter). So, I redeployed the GFO to resolve that issue.

 

[tj1627]

carbon dosing tends to become nitrate limited thus phosphate isleft behind. gfo is better at removing phosphate from the water column.

+1 While the bacteria fueled by carbon do consume nitrates AND phosphates, the ratio isn't 1:1. The consensus that I've seen from most threads is that nitrates get consumed faster and become limiting.

The benefit of carbon dosing + GFO as opposed to GFO alone is that the GFO will last longer since the bacteria are relieving some of the phosphate load when they consume it. Both working together seem to work pretty well for me.

 

[advancebc29]

just read a good article about this but cant remember where. the ratio is something like 16:1. so long story short you need to have a lot of nitrate in order for phosphates to be consumed.
I run biobellets plus GFO or my phosphates will start to increase.
The article then went into a discussion as to why zeovit consumes both so well. the theory was that the zeostart solution spikes nitrates briefly allowing the small amount of phosphates in the system to be consumed.

I have actually been thinking about trying zeostart and seeing if I cant shutdown my GFO reactor.

 

[Dwb859]

Thanks for the replies. I'm considering using MicroBacter7, which is suppose to consist of bacteria and enzymes for helping break down waste. I just need to decide whether I should start carbon dosing or not. My phosphate is 0.01-0.02 ppm and nitrate is 1-2 ppm. Is fish waste alone enought to support the bacteria population?

 

[Steve Wright2]

you already have bacteria in your tank Dwb859 , and many people would advise you that adding a bacterial supplement , is not required at this stage of your tanks development

carbon dosing, should you decide to go that route (read, read, think, read some more)
would be perfectly capable of increasing the amount of bacteria you have already

there are many people who have reported success with a combination of carbon dosing and bacterial supplement
but there are also a number of people that have succeeded without the need for any additional source of bacteria

 

[swcc]

If you decide to carbon dose it might be a good idea to remove your macro algae. If it starts dying off it will release all those nutrients back into your tank. Also, your nitrates and phosphates are reading low enough that you might just need to tweak your skimmer a little bit or even look at sump flow as a possible need for adjustment. Right now I am wondering how much skimmate your getting and the flow you have to your skimmer. also do you run any filter socks or sponge? I myself used to read about the same nitrate and phosphate levels as you. I removed my filter sock from my drain(I had changed it daiyt too) and slowed flow a bit thrugh my sump( went from 5x display down to 3x) and my skimmer started removing more and the levels both dropped to unreadable on my salifert test kits. Food for thought.

 

[dc]

[moved]...

 

[Dwb859]

If you decide to carbon dose it might be a good idea to remove your macro algae. If it starts dying off it will release all those nutrients back into your tank. Also, your nitrates and phosphates are reading low enough that you might just need to tweak your skimmer a little bit or even look at sump flow as a possible need for adjustment. Right now I am wondering how much skimmate your getting and the flow you have to your skimmer. also do you run any filter socks or sponge? I myself used to read about the same nitrate and phosphate levels as you. I removed my filter sock from my drain(I had changed it daiyt too) and slowed flow a bit thrugh my sump( went from 5x display down to 3x) and my skimmer started removing more and the levels both dropped to unreadable on my salifert test kits. Food for thought.

I have a reef octopus skimmer but only get about have inch of skim in the cup a week. I have a 150 gallon tank and the skimmer is rated for up to 250 gallon. I have 3 small tangs, two clown fish and a hippo tang. My display has about 100 gallons or so including live rock. My return pump with head pressure is around 550-600 gph. Did you slow the flow down through your sump with a ball valve on the drain?

 

[bertoni]

Carbon dosing is reasonable to try. It might be cheaper than GFO, and very likely is cheaper than growing and harvesting a macroalga. Some tanks end up requiring both GFO and carbon, though.

 

[jcw]

and very likely is cheaper than growing and harvesting a macroalga.

Huh? I don't spend anything harvesting macro. Not directly anyway.

 

[bertoni]

The lighting for the macroalga probably is the largest part of the cost, assuming it's in a refugium and not just lurking in the tank.

 

[Dwb859]

What is the different in adding a small amount of a bacteria supplement on a weekly basis vs. carbon dosing and bacteria? Obviously not as effective but it still seems like I would be increasing my bacteria population just not as rapid as with a carbon source? What do you think?

 

[bertoni]

I don't know whether such dosing would be very effective. Bacteria tend to be highly competitive, and a small addition once a week might not have much effect on the total population.

 

[reeksreef]

I was using both/either/or vinegar and vodka with some success, while running GFO. I opted to go with a solid carbon (bio-pellets) and removed the GFO to see the results. Although the pellets were able to get my NO3 to negligible levels, I wasn't able to get my PO4 below .08 (Hanna meter). So, I redeployed the GFO to resolve that issue.

Do you have a refugium? I'm running GFO and thought about adding bio-pellets.

 

[Dwb859]

I don't know whether such dosing would be very effective. Bacteria tend to be highly competitive, and a small addition once a week might not have much effect on the total population.

Should I even keep adding the bacteria then? What do you mean by they are highly competitive? I guess I just assumed the bacteria added just increased the population in my tank.

 

[Dwb859]

Trying to understand this better. Is the main difference in carbon dosing vs. just adding bacteria is that carbon dosing with increase my current population of bacteria where just adding bacteria may not allow that type of bacteria to establish because of the other bacteria?