Carbon dosing - method testing started

my opinion is
if the carbon source is the building block for the bacteria
all life forms being carbon based, and thus limited free carbon defines how much bacteria our systems can accomodate rather than nutrient availability
that in itself would account for the diminishing pellet size over time.
some of the carbon is lost, in order for bacteria to exist?

does that sound right?

 

Pellets will certainly get smaller. The reason people think carbon is sloshing off though is increased bacterial films on substrates of the aquarium and bacterial blooms in the water when overdoing Biopellets. In theory if the carbon was limited to the pellets, this shouldn't occur, but there are lots of accounts where it apparently has. Also people have noted increased cyan when using pellets, on the rocks and sand. This is also believed to carbon driven in some cases but shouldn't occur if the carbon is not being sloshed off.


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general update

Tank 2 - Vodka - having dosed at 0.05 mils for 3 days, and then 0.1 mil for following 4 days, today was 1st dose at 0.2 mils

Tank 1 - GFO - Rowaphos brand , I have decided to change the Rowa today
2 x table spoons have been in for 1 week only, but IMO the build up of film / micro algae on front glass over last 2 days ( 1st x 5 days glass stayed relatively clean and cleaner than the front glass on the other 3 set ups)
IME, the speed at which the glass become dirty, is the best indicator of when it has been time to change GFO in my other set ups

Steve

 

not sure if these images are going to show up very well
but lets see




I am on my second salifert test kit, and I still had one of the test tubes from previous kit in the cabinet, hence I was able to test 2 tanks at a time and take images

1st image tanks 1 and 2
2nd image tanks 3 and 4

it may be hard to see this on the images but
interpretting what I felt I saw on the results

Tank 1 - GFO , 2nd batch of 2 tablespoons - PO4 on Salifert looks like 0 to me
Tank 2 - Vodka - doing 0.2 mils per day last couple of days looks closer to 0.1 than 0 to me
Tank 3 - Bio Fuel - 1 mil per day , its not as clear as the GFO test kit looked, but its not at 0.1 IMO
Tank 4 - Bio pellets - definitely closer to 0.1 than 0


Nitrates next, fortunately this kit is OK with standard 10 mil test tubes of which I have plenty, so a row of 4 results will be captured for that image

Steve

 

rather dissapointing (and yes I realise its strange seeing that)

4 tanks have all returned 0 nitrate on todays testing

I believe this is partly because, I have stopped feeding the tank since introducing the carbon sources
in addition did a 10% water change after cleaning the glass etc 8 days or so ago
so no food stuffs combined with water change has probably helped in all 4 cases
to give the algae a chance to utilise the nitrate in these set ups

this means I need to change my method on the Bio Fuel and Vodka set ups already
in both cases, I will drop to either the maintenance dose Vodka ( back to 0.1mil) and the low nutrient dose for Bio fuel (0.5 mil)

nothing to change on other tanks although I will continue testing on a weekly basis, in addition to monitoring algae growth on GFO tank and change that as often as required to reduce that aspect of maintenance and compete with the algae for this nutrient

Steve

 

Would it be practical and more realistic to introduce an equal amount of livestock to each tank to maintain a balance of nutrient import? Otherwise, it's just going to be a race as to which tank becomes algae-free now in a zero-nutrient environment, which may not fairly equate the effectiveness of each method.

Just a thought...

 

Mr Bill

you have read my mind
I have been considering that since the Nitrate test result

Steve

 

Sounds good to me I think in the real world, there will be an infusion of nutrients, so, there should be in the experiment as well. I don't know if livestock is necessary, feeding would do the same really, but either way works.

Testing for nitrate though was IMO, a major flaw in Genetic and Stony_Corals Reefkeeping article for a number of reasons. To start, the second most important reason is that hobby grade nitrate test kits are not accurate. I won't get into this here, but R.H.F discusses this a lot for example if you do a search.

The most important reason though, is that, nitrate tests only tell you that nitrate is not being used up, by algae or other organisms, as fast as it's introduced. So, the only thing this really tells you is that there is a limitation, be it carbon, phosphate, iron, or even space for algae to grow. Getting a sustained nitrate reading of 0 just tells you that you've removed the limitation.

Really, what we want is for our desirable livestock to get the nitrate they need, without excess, to feed undesirable livestock. Right? So, if you have a tank full of algae, and no limitation, you could have a massive amount of N, entering the system and no detectable nitrate. On the other hand, you could have tank with very little nitrate entering the system, but have a limitation of iron, phosphate, or some other trace element, and therefore have no algae, but high nitrates, as there would not be any nutrient transport pathway for the nitrates, from the water column. Nitrate would then accumulate in the water; albeit at a very slow rate. So, adding nutrients may or may not result in a detectable nitrate reading. If it does though, it won't really tell you what you want to know. However, I think it is good to do, as you will at least know there is some free nitrate being introduced, although, you still won't know the dwell time.

The problem is there isn't a good well established and accepted indicator for what we want to know, which is essentially nitrate dwell time. If your not adding nitrate though, you know there is no nitrate to "dwell", other than from die-off from other organisms.
Everyone has their own ideas on the subject, my own is to watch the corals and watch for white bacterial growth on the rocks.

Given a fixed light output and spectrum, coloration indicates there is sufficient food in the water, be it bacterioplankton, fish-food, nitrate, trace element etc... If there is good color and no algae, then my goals are being met.

The actual color matters too though, dark brown coloration indicates excess nitrate or possibly carbon. R.H.F, for example hypothesizes carbon can result in browning, but this isn't documented in the scientific literature; if it is carbon, the indicator would have to be somewhat subjective based on the amount of carbon being dosed. If your adding a ton of carbon and getting brown coloration, this may indicate that, for example.

Nitrate, but not phosphate, is a well documented cause of browning in the scientific literature. Pigmentation, is the other component of color. Pigmentation, but not darkening almost certainly indicates, low zoox, but sufficient nutrients and energy to produce pigment. I hypothesize the most healthy corals are those that maintain a very colorful, but light appearance. Such "pastel" corals are often seen in carbon systems and in my experience are also the fastest growing. This makes sense for three primary reasons. First, it's well documented that nitrate (and also phosphate) slows down coral growth rates. Second, it's well documented that zoox produces radicals, which are harmful to the coral. And third, although research is still it's infancy, there is evidence that even SPS corals such as montipora can obtain 100% or more, of it's nutritional requirements from food, without any input from zoox; there will be some radicals and such from food, but there is no reason to believe the contribution would be nearly as great, so this could potentially result in faster growth and I believe does.

Bacteria on the rocks indicates that there is an accumulation of carbon in the system, going to a source that is benthic and difficult to remove. This results in an undetectable excess of other nutrients in the system, as this benthic bacteria also accumulates other nutrients, which are therefore not exported. This is an indicator of future headaches, therefore I try to avoid this.

For this experiment though, I think you may have to settle for introducing a reasonable bio-load for this sized system. Equal across the tanks. Perhaps adding a phosphate test would be reasonable, as once nitrate dwell time is low enough, phosphates should start to accumulate. Which may be a useful surrogate, as GFO isn't being used. However, PO4 is tough tough to test, although the Hach, Merk or possibly Hanna phosphourous checker, should at least tell you if your below .03. Combined with nitrate, this may be a reasonable indicator.

Maybe someone else has an idea though?

After that obstacle, I think removing the remaining algae and looking for grow back and your idea of adding coral to look at color and growth fits perfectly and will help answer a lot of questions.

 

Thank you m2434
I have quoted and will just refer to certain specifics here

Thanks again m2434, a very well thought out and written contribution
which gave me a lot to think about and also helped get my mind around certain aspects

 

thanks in no small part to m2434 for helping me to clarify my thinking on this test

My Salifert and Red Sea Phosphate and Nitrate test kits are no longer going to be of any use to use in monitoring conditions

but what we can do, as indicated by m2434 is monitor the conditions in the tanks themselves
After all, its the method most of us use when we are considering a change in GFO or activated carbon etc
and therefore will give us a measurable indicator of each methods performance

most of us carbon dose for aesthetic reasons, there are other means of removing / controlling N and P

the reason we carbon dose, is because we want extra bacterial capacity in order the bacteria out competes with algae for the available N and P

m2434s comments about cleaning and then monitoring can be put into practice, even before adding live stock

Today I have used a credit card to clean the front and the blue painted side of each tank
I used credit card, as it can be rinsed, and the paper towel dried before moving on to subsequent tanks (avoids cross contamination)

here are tanks 1 - 4 images taken 14. 20 Beijing time on 21st June
I will not clean any of these tanks for 7 days, and lets see what they look like on 28th June
Tank 1 - GFO x 2 Table spoons changed on 18th June in reactor

Tank 2 - Vodka - currently 0.2 mils each day

Tank 3 - Bio Fuel - 1 .0 mils each day

Tank 4 - Bio Pellets 100 grammes in reactor