algae growth control...?

[Ed]

Originally Posted by dfrmav

hmmm...interesting. i'll give it a shot!

in the future, is there a way to prevent this? boil the sphagnum?

Boiling the sphagnum won't make a difference. The spores can come from a variety of sources including dust, the plants added in the tank are two examples.

Ed

[Ed]

Originally Posted by rsain

Agreed completely. Even further some lab studies report that it wont reverse the existing algae just prevent future growth. So it seems that the results from empirical studies are a bit unclear - not sure exactly what mechanism is at work - nor which algae under what conditions it works for.

My uncontrolled experiment was just that - a once off thing based on a funny story - that yielded excellent results.

- Ryan

The literature actually indicates that studies on it began back at least in the 1970s, so I'm not sure what humerous incident your referring to... see http://www.sdstate.edu/nrm/outreach/...ae-control.pdf for example.

The problem is that the more studies that are done on it, the less indication is that it really works on a larger scale see for example http://www.btny.purdue.edu/pubs/apm/apm-1-w.pdf

There are several theories and some seem to be more probable than others.. for example the decoposition of the straw pushes a lot of carbon out into the system which encourages microbes to grow that cannot fix CO2 as the carbon source which in turn binds up a lot more of the phosphate which denies the use of phosphate to the algae (which is a limiting nutrient for them) resulting in a lack of growth of the algaes.

Changing the straw monthly may actually be disadvantageous to the system.

Ed

[rsain]

Originally Posted by Ed

The literature actually indicates that studies on it began back at least in the 1970s, so I'm not sure what humerous incident your referring to... see http://www.sdstate.edu/nrm/outreach/...ae-control.pdf for example.

The problem is that the more studies that are done on it, the less indication is that it really works on a larger scale see for example http://www.btny.purdue.edu/pubs/apm/apm-1-w.pdf

The humorous incident was the anecdotal discovery of the effects of the straw. I dont recall the decade and it's not that important - but the story goes that an accidental spill of straw into a pond eventually led to a clearing of the pond in terms of algae. Anecdote is just that - anecdote.

Just to be clear. 'm not referring to large scale use - rather small scale. A 500g pond is hardly large scale.

I've also looked at the research when I first started using this - and found the same stuff you did. It's not clear if it does work at all and if it does it seems to be both temperature and species specific (both species of the algae and of the straw used).

http://www.google.com/url?sa=t&rct=j...MbW4Wg&cad=rja

http://www.google.com/url?sa=t&rct=j...oC8e7Q&cad=rja

Originally Posted by Ed

There are several theories ... [snip]

Changing the straw monthly may actually be disadvantageous to the system.

Ed

Agreed about the theories - my statement came from the literature about not being 100% sure of why it works. But the model you presented is the likely one according to what I have read.

With my pond - and I can only speak to mine - I had to change the pad about once a month for several reasons. First that the water would begin to turn green and second the darn thing was virtually gone from decomp. Again I'm talking a very small pad here.

If the decomp and competition model is correct then one would only change the straw (or better yet, just add to it) after it has 'lost it's value'.

I'm not arguing with you - in fact I agree completely - it's an interesting and inexpensive method that has much anecdotal and some empirical support. From my reading the scientific jury is still out.

- ryan