Liquid Carbon, Excel, Glutaraldehyde — Small research

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Feb 26, 2023

2.5% 3% Glutaraldehyde — (CH2)3(CHO)2}) — The molecule consists of a five carbon chain doubly terminated with formyl (CHO) groups or Polycycloglutaracetal
— Excel lists "polycycloglutaracetal" which is not the above mentioned chemical exactly. "Polycycloglutaracetal is an isomeric form of glutaraldehyde”. The isomer actually helps keep the aqueous form stable to increase half life.
My Note: maybe it is for that that some fabricants put the number of days it will remain effective (e.g. 28 days)???

Warning: Some plants are known to be sensitive to “Liquid Carbon”, such as Vallisneria and Anacharis.
My Note: I really doubt that Excel have any detrimental effects on plants if dose correctly???

Scientific Paper ————————————
Glutaraldehyde behavior in aqueous solution, reaction with proteins, and application to enzyme crosslinking.

- Glutaraldehyde possesses unique characteristics that render it one of the most effective protein crosslinking reagents.
- Glutaraldehyde, a linear, 5-carbon dialdehyde, is a clear, colorless to pale straw-colored, pungent oily liquid that is soluble in all proportions in water and alcohol, as well as in organic solvents. It is mainly available as acidic aqueous solutions (pH 3.0–4.0), ranging in concentration from less than 2% to 70% (w/v).
- In practice glutaraldehyde is sold as a 2% solution, buffered on the acid side, and sodium bicarbonate is added to activate it (pH 8) just before use. The active solution has to be discarded after 14 days because of polymerisation. Various surfactants, such as magnesium dodecyl sulphate and blends have been used to speed up biocidal activity of an acidic solution of glutaraldehyde, therefore retaining greater storage stability without the need for activation. Quaternary ammonium compounds are also claimed to improve stability and effectiveness in some applications.

Other Study ————————————
Study performed using a river water-sediment system found that glutaraldehyde degraded rapidly under both aerobic and anaerobic conditions.

In this system, glutaraldehyde was found to partition primarily to the water phase, with a pseudo-first-order half-life of 10.6 hours under aerobic conditions and 7.7 hours under anaerobic conditions (Leung 2001).
Glutaraldehyde was stable in sterilized control samples maintained at pH 5 and 7 for 31 days; however, at pH 9, 30% was degraded, primarily to a cyclicized dimer of glutaraldehyde, 3-formyl-6-hydroxy-2-cyclohexene-1-propanal. Extrapolated half-lives for abiotic degradation of 508, 102, and 46 days at pH 5, 7, and 9, respectively were calculated.

Under aerobic conditions, glutaraldehyde was found to degrade to glutaric acid and subsequently carbon dioxide, whereas under anaerobic conditions, it was degraded into 5-hydroxypentanal followed by 1,5-pentanediol
glutaraldehyde —> glutaric acid —> carbon dioxide

Glutaric acid (Pentanedioic acid formula) has been detected, but not quantified in, several different foods, such as eddoes (Colocasia antiquorum), pitangas (Eugenia uniflora), narrowleaf cattails (Typha angustifolia), chicory leaves (Cichorium intybus var. foliosum), and wax apples (Eugenia javanica)

Excel reducing the Biofilm on the surface of the leaves help photosynthesis? ————————————
Epiphytic biofilms on Water plants leaves can lead the encapsulated leaf in limiting both its photosynthesis and respiration. The epiphytic biofilm is comprised of an autotrophic community made up of diatoms, green algae, and cyanobacteria, and a heterotrophic community consisting of bacteria, protozoa, fungi, and other microorganisms.

(This is why a certain degree of water flow is helpful for plants to access nutrients in the water columns.)

The experiment calcul O2 concentrations and pH gradients and calculate fluxes of O2, CO2 and bicarbonate (HCO−3) around seagrass leaves (Z. marina L.) covered with artificial, inactive biofilms and natural epiphytic biofilms.

(Note: Bicarbonates: For plants living completely submerged in water, CO2 is limited and many of these plants have developed a mechanism to tap into other carbon sources. In this case, they extract it from bicarbonate )

— A sterilized seawater-agar matrix was used to make an artificial “inactive” biofilm on seagrass leaves with the same thickness as the natural leaf epiphytic biofilm, which impeded exchange of gases but did not have microbial activity.

— We compared both “active” and “inactive” biofilm to investigate the effect of microbial activity and molecular diffusion in seagrass leaf biofilms.

— In light (were the plant releases oxygen and capture CO2 and carbonates)
the O2 flux of leaves with inactive biofilm was only 31% of the leaves with active biofilm, indicating that the photosynthesis of the microbial community in the biofilm makes up the majority of O2 production in the leaf microenvironment.

— increase in pH of 1 unit in the “active” biofilms and only 0.3 pH units in the “inactive” biofilms
(Ideal ph for nutrients plant absorption 6 to 7 ph) (

— In Darkness (were the plant releases CO2 and retain Oxygen)
— O2 fluxes were almost identical in the “active” and “inactive” biofilms.
— both biofilms show a decrease of ~0.3 pH units in darkness

Epiphytic biofilm (Active Natural) activity thus strongly affects the seagrass leaf microenvironment in the light by inducing higher O2 concentration and pH, increasing CO2 limitation and reducing the leaf photosynthetic efficiency. The Epiphytic biofilm therefore extends the molecular diffusion time and restricts nutrients and gas exchange between seagrass leaves and the surrounding water.

My Resume ————————————
Why it work?
Excel (Glutaraldehyde), why it can work in Aquaria:
— Glutaraldehyde is a Bactericidal, virucidal, sporicidal and fungicidal use as disinfectant for medical instruments
— Help reduce the bacteria biofilm film on freshwater plants leaves to permit better absorption of nutrient
— Help kill algae spores and probably kill some bacterias. fungi and other micro organism in suspensions in the water.
— In water, glutaraldehyde biocide ability will degrade quickly (10 to 15 hours). Depending on how much oxygen is available in the water, glutaraldehyde might turn into carbon dioxide or 1,5-pentanediol.
— Glutaraldehyde, at Excel standard dose releases around 2 ppm of carbon over 10 to 15 hours (around 0.2 ppm per hour and going down) — Normal Atmospheric equilibrium provides 3-5 ppm of CO2, 15-25× more CO2 than "liquid carbon".
— In practice glutaraldehyde is sold as a 2% solution, buffered on the acid side, and sodium bicarbonate is added to activate it (pH 8) just before use. The active solution has to be discarded after 14 days because of polymerization.
— Seachem pretend that it’s reducing effect help keep iron in a ferrous state (more available for plants)
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