Article on biofilm

[ButtNekkid]

https://tanninaquatics.com/blogs/news/biopellets-another-useful-idea-from-the-salty-side

 

[gerald]

Good article. Biofilms are THE foundation of life in most streams and rivers. Other major components of biofilms are Fungi, Archaea, and Protozoa, along with Bacteria as discussed in this article. One item I read that could have been explained a bit better in the article is this [referring to crowded or overfed tanks]:

"... there is always the possibility that bacteria within the biofilms can multiply extremely rapidly, reducing the level of oxygen in the rest of the aquarium, which could lead to a dramatic reduction of CO2 being released out of the water. This, in turn, could lead to CO2 levels rising quickly and sharply, ... "

What the author apparently meant to say was that excessive bacterial respiration could lower the water's dissolved oxygen AND increase CO2. These effects happen at the same, rather than one "leading to" the other. The phrase about "reduction of CO2 being released out of the water" was also confusing. ... I left him a comment on the website.

 

[ButtNekkid]

https://tanninaquatics.com/blogs/news/humic-substances-in-freshwater-aquariums

 

[gerald]

Nice one - i'm saving a copy of that. So, what exactly happens to tannins/DOC in water that has enough KH that it doesn't darken? There's certainly no shortage of leaves and wood in the watersheds of clear-water streams. How does KH destroy the DOC? Or is it something else? In eastern North Carolina I see many soft blackwater streams, but they're not always strongly acidic. Many are near neutral pH (6.5 to 7.2).

 

[dw1305]

Hi all,

So, what exactly happens to tannins/DOC in water that has enough KH that it doesn't darken? There's certainly no shortage of leaves and wood in the watersheds of clear-water streams. How does KH destroy the DOC? Or is it something else? In eastern North Carolina I see many soft blackwater streams, but they're not always strongly acidic. Many are near neutral pH (6.5 to 7.2).

They are independent processes, you can have hard water that is tannin stained, but it is more unusual.If you have flow the availability of carbonates and oxygen will lead to clearer water.

When you have hard water you have a lot more microbial, and invertebrate, activity and biodegradable material does last as long, or build up, in the same way that it would in less carbonate rich water. Wood etc can still accumulate, but more biodegradable items are quickly re-cycled.

We have a small water-shed on campus (small stream, spring fed, hard water) and as soon as you get into areas of woodland the stream has huge numbers of Gammarids, busily shredding leaves etc.

cheers Darrel

 

[gerald]

Has anybody tried crepe myrtle (Lagerstroemia) bark as a tannin source? It's a popular ornamental tree in the USA that sheds its outer bark in mid-summer, so there's plenty of shed bark piles all around my neighborhood. Just wondering how good and/or safe it might be for fish and shrimp.

 

[Akraziatic]

Awesome articles! Had me following links deep into the internet. I only recently started diving into "natural" tanks using the walstad method which certainly opened my eyes more than the heavy filtered monster tanks. Definitely bookmarking this for a future display build, keen to try it out.