Glucose additions causes cyano & algal problems in addition to coral problems.

[HighlandReefer]

When I dosed glucose it did result in a rapid increase in both cyano and algal problems.

I am wondering if there is a hobby grade test that can measure the glucose content in a reef aquarium? What might be an effective method to reduce glucose in a reef aquarium?


Effect of inorganic and organic nutrient addition on coral-algae assemblages from the Northern Red Sea
http://cat.inist.fr/?aModele=afficheN&cpsidt=22102584

From this article:

"Abstract
Previous studies in fringing reefs of the Northern Red Sea demonstrated that the in-situ competition of corals and algae in natural assemblages is highly variable between seasons displaying fast overgrowth of corals by benthic reef algae in fall that follows close to equilibrium between both groups of organisms in summer. This may be caused by up to 5-fold higher inorganic nutrient and 6-fold higher organic nutrient concentrations in fall and winter, thereby potentially promoting algae and cyanobacteria growth with concomitant phase shift. A long term mesocosm experiment (duration: 90 days) was conducted in order to study the effect of dissolved inorganic (ammonium, phosphate, nitrate, and mix of all three) and organic (glucose) nutrient addition onto the competitive process in the dominant coral-algae assemblages of the Northern Red Sea involving branching corals of the genus Acropora and a typical consortium of benthic turf algae. Nutrients were added in 3-fold higher concentrations compared to the annual averages, and the parameters algal growth, extension of bleached area on corals, tissue colour change and chlorophyll a concentrations were monitored at regular intervals over experimental duration. This revealed that elevated ammonium concentrations and elevated organic nutrient concentrations stimulate algal growth, while coral tissue pigmentation and chlorophyll a content were significantly decreased. But only in the elevated organic nutrient treatment all effects on corals were significantly pronounced when assembled with benthic turf algae. Supplementary logger measurements revealed that O2 water concentrations were significantly lower in the elevated organic nutrient mesocosm compared to all other treatments, confirming side-effects on microbial activity. These findings indicate that organic nutrient input into coral reefs can affect physiology and metabolism of both corals and benthic turf algae. Reinforcing interaction between both groups of organisms along with involvement of microbes may facilitate phase shifts in coral reef ecosystems."

 

[HighlandReefer]

I also wonder if high glucose levels in a reef tank may be a reason for some of the mysterious coral problems that hobbyists seem to run into?

 

[toaster77]

i think that levels of free glucose are going to very very low to non-existent in the ocean. it is such a universal carbon source for so many organisms that if there were any free glucose it would certainly be taken up and metabolized very quickly by almost anything.

if you dosed glucose i could certainly see it promoting growth of cyano, algae, and almost everything else without any selection in favor of the good stuff. but i bet very quickly you would not be able to detect it anymore as it would be so rapidly consumed. hth.

 

[HighlandReefer]

My major concern is the glucose content in a reef aquarium. I have seen no studies on reef aquariums as to what this content might be. I thought with the high organic content in a reef aquarium which has been documented that perhaps the glucose content may be greatly elevated as well since the bacteria, algae....etc would be braking the organic chemicals down constantly. In addition many of the foods added are high in glucose. :worried:

 

[kfisc]

So, if you had to do it all over again, and short of any introduced problems or mishaps along the way causing a switch, which carbon source would you use?

 

[HighlandReefer]

There seem to be two major reasons for dosing carbon sources. To reduce nitrate and to achieve healthier coral.

When dosing for healthier coral, the amount and type of carbon source may be quite different and the amount you dose would be greatly reduced. IMHO this is a completely different realm.

When dosing a carbon source to reduce nitrate without algae concerns (problem species in your tank), I like the vinegar the best. Vinegar seem to produce good coral growth and less cyano problems for my tank. Even without algae problems every tank most likely has different micro-organism populations which can produce different results with different carbon sources.

I would suggest slowly experimenting with the carbon sources under as controlled an environment as possible.

Perhaps dosing a carbon source is not the best way to reduce nitrate as far as its effect on the micro-organism populations. The additional DOM produced by the carbon sources may have detrimental effects on your tank inhabitants. I would not discount the other methods of reducing nitrate such as nitrate reactors, using macroalgae, deep sand beds, good quality skimmers, filter bags, diatom filters....etc. IMHO, you are better off using the other methods for reducing nitrate if possible.

 

[tmz]

I had troubles with sugar dosing ,sucrose in very small amounts !/4 tsp per day for 550 g,in my case. Some lps reacted very badly, closed/gaped, after about 10 days two specimens were lost.

Systems are different but FWIW ,I'm having very good results in terms of coral health, algae and cyano control and PO4 and NO3 levels with vodka and vinegar .at 24 ml vodka and 60 ml vinegar per day for the 550gallons. Note vinegar is about 1/8 as strong as vodka in terms of carbon content so the 60 ml equates to about only 8ml of vodka.

 

[HighlandReefer]

Tom,

Are you currently running your nitrate reactor?

 

[toaster77]

My major concern is the glucose content in a reef aquarium. I have seen no studies on reef aquariums as to what this content might be. I thought with the high organic content in a reef aquarium which has been documented that perhaps the glucose content may be greatly elevated as well since the bacteria, algae....etc would be braking the organic chemicals down constantly. In addition many of the foods added are high in glucose. :worried:

i think high organic content in water can lead to several things 1. some of these organic compounds could be toxic to certain species/inhabitants, and 2. some bacteria, algae, etc. could use these organic compounds to make glucose for themselves, usually for their own growth. my impression is that it would be unusual for them to make glucose and then secrete it, they are going to be selfish But as you can see in this manner the high organic content could lead to growth of some bad guys.

 

[HighlandReefer]

Perhaps the food additives glucose content could be a major concern regarding algal, cyano and coral concerns?

 

[HighlandReefer]

I've been trying to pull this article up but their server is down for maintenance. I don't remember if it included glucose content in the lists. :lol:

Necessary Nutrition, Foods and Supplements, A Preliminary Investigation
http://web.archive.org/web/20010720071031/http://www.animalnetwork.com/fish/data/foods.asp

 

[toaster77]

Perhaps the food additives glucose content could be a major concern regarding algal, cyano and coral concerns?

well, it's sort of a double-edged sword kinda thing - the foods should contain some glucose or other carbs for the fish (after all, they and us we all need carbon ) but yeah, certainly if you overfeed or don't skim well enough, this extra glucose and carbs could then end up feeding the bad guys too much!

 

[HighlandReefer]

Perhaps a significant amount of the fish food glucose can dissolve in tank water before it can be consumed by fish?

 

[HighlandReefer]

How hard is it to run a glucose test on reef tank water?

 

[HighlandReefer]

According to this article it sounds pretty difficult to determine sugar contents in sea water: :lol:

Determination of sugars in unconcentrated seawater and other natural waters by liquid chromatography and pulsed amperometric detection.
http://pubs.acs.org/doi/abs/10.1021/es00025a014

 

[tmz]

Tom,

Are you currently running your nitrate reactor?

No,Cliff. I haven't used the sulfur denitrator in about a year. In my experience it was great for dropping high nitrates 60 to 80ppm to 0 but isn't very effective in a long term application. I can't quite get the flow rate balanced to avoid hydrogen sulfide when the nitrates are low.

With the carbon dosing and no reactor nitrates have held at 2.5ppm to 5ppm. PO4 runs around .05/.06ppm. I do run a chaeto refugia, gac and gfo.

 

[philbo32]

Bacteria will utilise glucose for its individual molecules; C6H12O6, and will be able to break down individual components of the molecule. They will be able to use each compenent, depending on the type of bacteria. This molecule is similar to all other sugar type molecules like a lot of organic solvents including vodka, therefore the same bacteria will be able to break glucose down the same as organic solvents. At the same time these bacteria can use NO3 and PO4 during respiration. It has been hypothesised that bacteria prefer NO3 but will store and use PO4 when NO3 is reduced and will beable to use it for respiration. Cyano is also a bacteria and can feed on this carbon source and N2 directly which can give it the advantage. If you dose bacteria then you should be able to raise the amount of bacteria and outcompete the cyano.

 

[toaster77]

Perhaps a significant amount of the fish food glucose can dissolve in tank water before it can be consumed by fish?

I'm guessing this would depend on how much the manufacturers spike free glucose or other carbohydrates into the foods (probably so for pellets, flake food, etc. but dunno about mysis, brine shrimp, etc.). If they do, then certainly you can imagine these carbs leeching into the water as soon as they are added to the tank.

Otherwise then the glucose content in mysis, brine, etc. is often stored as glycogen or other polymers within those animals cells and they would require digestion by the fish to be liberated, but at the same time, any uneaten, excess food would slowly decompose thereby releasing carbs etc into the water.

 

[HighlandReefer]

I'm not convinced that dosing bacteria will help bacteria out-compete cyano or algae. IMHO, I believe that you need to change the tank environment toward a situation which is less conducive to the cyano and algae. The above study is the first I have found where high levels of glucose (3X) cause significant algae & cyano population shifts. The concentration of glucose seems to be able to increase significantly in certain areas of the ocean, especially where pollution occurs. In comparison to the pristine ocean areas, I consider our reef tanks more closely related to the polluted areas of the ocean, when you are talking about the level of organic material present.

The above study is not the only one that has found that high levels of DOC (in general) cause cyano and algal problems. Some studies have found that higher nitrate levels have little impact on cyano and algae as long as the phosphate level is low. These studies did not try to separate the DOC content in the ocean though.

FWIW, if increased glucose levels (only 3x that of the ocean) can cause increased populations of algae and cyano with bleaching in coral, I don't see why this can't occur in our tanks, especially if the tank is fed heavily.

 

[HighlandReefer]

I'm guessing this would depend on how much the manufacturers spike free glucose or other carbohydrates into the foods (probably so for pellets, flake food, etc. but dunno about mysis, brine shrimp, etc.). If they do, then certainly you can imagine these carbs leeching into the water as soon as they are added to the tank.

Otherwise then the glucose content in mysis, brine, etc. is often stored as glycogen or other polymers within those animals cells and they would require digestion by the fish to be liberated, but at the same time, any uneaten, excess food would slowly decompose thereby releasing carbs etc into the water.

I agree. I feed my fish Mysis that are vitamin fortified. Hopefully the vitamins added do not include glucose or carbohydrates.