Carbon dosing without a skimmer ...

[Reef_Curiosity]

I fully understand this and I am not doing it for nutrient reduction hence the skimmerless part.

The concern that I have is that the carbon dosing will hit the biological filter (...)

(...)will the "bloom" continue to consume nutrients and go straight to filter feeders and thus act as a de facto skimmer leaving the biological filter weakened

(...) will most of it make it back into the tank thus liberating the consumed nutrients. (...)

Hi,
I carbon dose on 3 tanks, 2 of which are without skimmers.
I believe you are overthinking this, but I understand your concern!

Carbon dosing will not "hit" your biological filtration. I read it in a negative manner. It does not ruin your rock's biofilm in any manner, don't worry.
Only overdosing, to the extent that massive bacterial blooms remove the oxygen, can harm the biofilm which requires oxygen.

The bloom will not continue to consume nutrients. Only if you overdose. It's limited by the carbon source (i.e. you control it).
Remember, the carbon you add is quickly respirated to gas by organisms, and will leave the aquarium.

The bacteria you "bloom" with the dose will be eaten and recycled. Or die off and decompose so the N and P eventually returns to the water column. But there will be less N and P available in the water, than there was before you dosed.
Your goal is to have that N and P recycled into corals through feeding on the bacteria, in a tank where carbon dosing is used as a coral food and not for skimmer collecting.

 

[HuduVudu]

@Reef_Curiosity thank you very much for the information.

 

[ceaver]

I have worked out the issues with lower demand on a CaRx but I am getting too much alk. Hilariously I tried to push up the calcium to balance the higher alk using calcium nitrate. This was a giant fail because I have plenums and the alk went through the roof.

Now I have the alk at a reasonable level but my calcium is now out of balance and VERY low and pushing the reactor up just moves the alk up. I am now using acetic acid on Kalk to get calcium and this is working.

Interesting, thanks for all the background context! Stupid question here --and I don't understand the chemistry behind what happened with your plenums-- but what if you just dosed a typical calcium hydroxide supplement to get your calcium back up and in line with alk, to then let the reactor take over?

 

[ReefGeezer]

...Carbon dosing will not "hit" your biological filtration.

What do you mean by "hit"? Why doesn't it "hit" the biological filtration?

...carbon is quickly respirated to gas by organisms.

How?

 

[Randy Holmes-Farley Verified Community Expert]

I am using vinegar on kalk for calcium and will also use it on mgco3 for mag. I am using quite a bit (I think) 8ml/day on 5% acidity (whatever that means, it's what the bottle says). I am trying to balance a system that got out of whack.

In your opinion would be better to ramp down the usage or can I just cut it off when I don't need it. If you want to provide your reasoning that would kewl too, from an educational stand point.

EDIT: If you are feeling like adding a bit more it would be nice to know what is the breakdown path for the acetate.

EDIT:EDIT: Is DOC Dissolved Organic Compounds or Dissolved Organic Carbon?

DOC is literally dissolved organic carbon, and the related terms are DON and DOP for N and P, and POC, PON, and POP for particulate forms. DOM is a generic term for dissolved organic matter.

I expect that you can cut it off cold turkey and bacteria reliant on it (if any) will just slowly fade away.

 

[HuduVudu]

but what if you just dosed a typical calcium hydroxide supplement to get your calcium back up and in line with alk, to then let the reactor take over?

I am still getting alk from the Kalk. My alk is already much higher than my calcium and even though over time the Kalk will bring it back in line that could be a very long time with the difference between the two ... ~8.4dKh to 310ppm. Also I am not sure how the ratio will play out with my tank. Things got way out of whack and this is a corrective measure, my alk went all the way up to 11.5dKh with Ca at 320ppm. My mag is also low (900ppm) and I need to work it back up. The tank seemed to be happiest at 7.7dKh and ~420ppm Ca and 1200ppm Mg I am trying to get in that area without force things into those parameters. We will see what the tank wants to do.

I also think that the CaRx design is causing some issues with the imbalance because of the way that I am running it, and I am working on corrective measures with it. All of this takes time though, so some temp measures are in order.

 

[Reef_Curiosity]

What do you mean by "hit"? Why doesn't it "hit" the biological filtration?


How?

As I said, I read the "hit" in a negative meaning, as in ruin or damage.

How? Through respiration.

 

[fryman]

I carbon dose on two tanks, a 16 gallon without skimmer and a 120gallon with a skimmer. My goal is primarily to control nitrates.

Oddly the 16 gallon one responded much faster to carbon dosing with nitrates quickly reduced this way. In contrast the 120 gallon with skimmer took months to work, but eventually I got it dialed in as well.

I get the theory about a skimmer helping remove extra bacteria but I think this is just the prevailing theory. There's plenty of evidence carbon dosing can work without a skimmer.

That said, a skimmer has other benefits and probably helps carbon dosing, so if you can get one I think it's better.

 

[Subsea]

I'm not sure that is entirely true. Every time an organism consumes the bacteria, some of the N and P likely goes into building more tissue.

There's no theoretical reason one cannot use carbon dosing just to provide food. It's certainly no worse from a nutrient accumulation perspective than actually adding new foods.

Many years ago, as superintendent at municipal waste water plant designed by Schriver, a German consulting company, we stressed nitrification bacteria with reduced oxygen causing increased phosphate uptake to repair bacteria membrane.

 

[ceaver]

I am still getting alk from the Kalk. My alk is already much higher than my calcium and even though over time the Kalk will bring it back in line that could be a very long time with the difference between the two ... ~8.4dKh to 310ppm. Also I am not sure how the ratio will play out with my tank. Things got way out of whack and this is a corrective measure, my alk went all the way up to 11.5dKh with Ca at 320ppm. My mag is also low (900ppm) and I need to work it back up. The tank seemed to be happiest at 7.7dKh and ~420ppm Ca and 1200ppm Mg I am trying to get in that area without force things into those parameters. We will see what the tank wants to do.

I also think that the CaRx design is causing some issues with the imbalance because of the way that I am running it, and I am working on corrective measures with it. All of this takes time though, so some temp measures are in order.

I am sorry, face palm over here, what I meant to say was calcium chloride. I have no idea how I typed calcium hydroxide in there instead of calcium chloride! Sheesh, long day, I guess. I'm sure there's a good reason calcium chloride won't work either, but yes, very clear that calcium hydroxide wouldn't. I guess that really was a stupid question lol!

 

[ReefGeezer]

As I said, I read the "hit" in a negative meaning, as in ruin or damage.

How? Through respiration.

I wouldn't say it doesn't do any damage. It will result in less nitrifying bacteria as opposed to the same system not using carbon dosing. That's why suddenly stopping after prolonged carbon dosing is not recommended. Small doses used to create a food source probably have little impact. Larger doses used to control nutrients may.

Ok...yea... but that carbon, CO2, is used by other processes or escapes to the atmosphere. It is not returned to the system as organic carbon.

 

[Randy Holmes-Farley Verified Community Expert]

Many years ago, as superintendent at municipal waste water plant designed by Schriver, a German consulting company, we stressed nitrification bacteria with reduced oxygen causing increased phosphate uptake to repair bacteria membrane.

Certainly, any tissue growth or repair requires both N and P.

 

[Subsea]

I'm not sure that is entirely true. Every time an organism consumes the bacteria, some of the N and P likely goes into building more tissue.

There's no theoretical reason one cannot use carbon dosing just to provide food. It's certainly no worse from a nutrient accumulation perspective than actually adding new foods.

@Randy Holmes-Farley
I am growing Gracilaria Parvispora in a monoculture 55G tank that is three months into cultivation, using ammonia and ChaetoGrow along with passive alkalinity and trace mineral addition from solubility of aroggonite. Biomass doubles every 10 days. I anticipate having to dose phosphate. Would vinegar provide carbon uptake for this Red Ogo monoculture? I just did harvest 1 pound and moved from 20G tank to 55G tank. While I do sell to LFS, the seaweed is for my consumption in specialty salads and cheviche.