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Re: Algae Sequestering of Nutrients (was Plant eating SAE's)

At 11:32 AM 1/7/99 -0500, you wrote:
>Subject: Plant eating SAE's? 
>From: krandall at world_std.com
>First a brief comment on the role of algae in freshwater aquariums:
>>Our first line of defense is, or should be, our plants.  
>>But there's nothing wrong with using algae as PART of the nutrient 
>>sequestering process, and then allowing it to feed some of the animals 
>>we wish to keep.
>In nature, algae play a dominant role in nutrient sequestering. I suspect
>this is also true in areas where vascular aquatic plants are also present.
>In our planted freshwater aquaria, I hope that the algae represent such an
>insignificant fraction of the biomass that their contribution to nutrient
>sequestering would be extremely unimportant. 

That's why I said the higher plants should be the first line of defense.<g>

> Now, on to the more interesting question:
>>thing I've noticed is that a lot of the people who are advocating the use
>>of bleaching to totally avoid the introduction of filamentous algae, also
>>seem to have a fair amount of experience with green water. (they also
>>mostly use soil substrates, it seems to me) They seem fairly nonchalant
>>about it, and seem willing and able to cope with the occasional bloom.

>OK, I fess up. I use soil in my tanks. (a small amount, perhaps equivalent
>to the amount recommended for laterite). Occassionally, I get green water
>in one of these tanks. But, I am not sure I put myself in the category of
>bleaching to totally avoid the introduction of filamentous algae. I just
>like to avoid two or three species. <g>  If I had a moderate level of
>copper in my tanks, I would not be as concerned.

My impression of you and your tanks is that you aren't "rabidly" in any one

>>is one of the REASONS they see more green water at least partially because
>>they limit the number of other types of algae that are present within the

>We know that many different types of algae do not seem to co-exist in
>equally large numbers in the aquarium. Many species are undoubtedly present
>simultaneously, but a few types seem to dominate at a particular time. I
>suspect that has to do with preferential nutrient ratios and
>allelochemicals. If the later is the reason, these same chemicals may be
>affecting the higher plants. So, this is another reason that I do not want
>to have any attached algae in my tanks - if I can help it. 

I have no proof of course, but as much as I like the theory of
allelochemicals, I have the strong feeling that most of the incompatibility
we see is caused by preferential nutrient ratios.

>That is not to say that I never see any attached algae. I do occassionally
>have to clean the front glass and see a speck or two on the leaves.<g>  In
>the more quiet areas which do not get a lot of water circulation, a small
>clump of filamentous algae can also be found. When I start to notice other
>algae, however, it tells me that something is wrong in that tank. Because
>when the plants are going gang busters and sending out their daily streams
>of bubbles, the algae does not have a chance. I don't keep as big an
>arsensal of algae eating animals anymore -- I only have a pair of farowella
>and one SAE (its friend recently jumped out) :-(   
>There is also nothing prettier than a tank full of algae free plants. They
>seem to sparkle!

I agree.  As I said before, I keep SAE's because I like them.  I like some
other fish that happen to eat algae too.  I don't keep them for the sake of
algae control per se.  I have tanks with _no_ algae eaters that do not have
algae problems.

Like you, I see algae, including filamentous types show up when I've
neglected a tank for too long. (usually we're talking months here, not
days<g>)  And like you, it is most likely to be seen in areas with little
water movement.  One of the first (usually the only) places I see it is on
top of mats of leaves that are choking the surface because I haven't
"weeded".  I think this is _perfect_ algae territory:

* no water movement to speak of
* LOTS of light
* build up of nutrients from dying (singed by the lights<g>) plant leaves,
and from fish food that doesn't make it's way into the water<g>
* no algae eaters that can get through the mat of leaves to eat it

>>_Something_ is likely to make use of any excess nutrients available in the

>In my case, algae is only taking care of excess nutrients when I carelessly
>or inadvertently introduce some phosphate laden soil particles into the
>water column. This mostly happens when I uproot particular plants (the soil
>doesn't necessarily start out with a lot of phosphates, but over time I
>believe it soaks it up from stuff which precipitates out of the water. Same
>with laterite, except that laterite's particles are larger and do not
>appear to stay suspended as long). I would like to hear from others that
>get green water to see if there is any connection to choice of substrate
>materials. Any laterite users out there? <VBG>

Yup. You know I'm one.  The only two times I've ever had green water was
right after the use of DAI tablets, which we know contain phosphate.  I
think we can pretty well lay the blame at their door.  

> Also, it would be
>interesting to hear from others who may be using undergravel heating to see
>what kinds of algae if any they see.

Me too.  

Gee, is it possible that this conversation will actually produce more
lumens/watt than many here recently?<g>

Karen Randall
Aquatic Gardeners Association