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Re: Aquatic Plants Digest V3 #763

>From: Liisa Sarakontu <lsarakon at cc_hut.fi>

>I guess that about 95 % of all SAE owners have witnessed this behaviour
>every now and then!
Hi Liisa. Always good to hear your interesting commentary on SAEs. 
>From: "Christopher Coleman" <christopher.coleman at worldnet_att.net>
>I also suspect that there is some relationship between the
>movement of "important" ions  ( Ca, Mg, K ) inside and outside the plants
>which hasn't been discussed.  Toward that end, I have purchased a LaMotte K+
>test which will supplement Mg+, and Ca+ tests I  have and will be used to
>monitor Ca, Mg, and K ion levels in the weeks and months ahead.

I too suspect that the _relative_ concentrations of these chemicals in the
water column is very important.... at least for some plants. I have soft
water which is therefore "unstable" in the presence of adding stuff
(fertilizer, Ca tabs, etc) in a tank with lots of plants. For example, my
E. tenellus can vary from 10cm to 25 cm over time in the same tank and
other tanks have had their plants increase in height or completely stop
growing when I "play" with the mineral content. The plants are also causing
change by growing,  sucking up (or releasing) nutrients and with luxury
consumption.  I did not know that LaMotte had a K+ test. Keep us informed
of the variation in levels.  

>Here is some of my very preliminary thoughts. It is fairly accepted
>that potassium plays a role in osmotic balance.  With the K+ test, I
>am  hoping to quantify the deltas in the water column of K, and hopefully
>find some meaningful correlation between the three ions of Ca, Mg, and
>K and to establish that these ions move into AND OUT OF the plant.

As leaves die, the minerals will be released again. This may be difficult
to control.

>2) that the nutrient uptake in aquatic plants is more osmotic in nature than
>    we have preveously given credit.  This would lend support to my belief
>    that you can have a deficiency of an ion within a plant even when
>    levels of that  ion exist in the water column.

Another thought is that when the mineral balance is upset, the plants can't
take in certain needed nutrients. This may be why there are plants better
adapted to hard or  soft water and why an aquarist can royally screw things
up when they start to randomly add chemicals. (e.g. "over correcting" for
Mg defieciences by adding too much Epsom Salt). I suppose the same can
happen with Potassium (say by using KNO3 to supply N in combination with a
fertilizer already designed to provide K). I know that I have messed up one
tank when I was playing with coral rock in the filter and the KH gradually
increased from 4 to 8. At first, I thought it was great because lots of
different plants started to grow faster and taller. I had some Sag which
was stable in that tank for 2 years that increased noticeably in height.
Same for the Echinodorus. The crypts loved it. But other species were much
less tolerant. I almost lost all the ferns. and Hemianthus stopped growing.  

>3) that the roots of aquatic plants play a more important role in uptake
>of Ca, Mg, and K ions than has been mentioned.

I believe plants need these minerals in the water column... but are
probably not getting all of it from the water. e.g. tetra crypto tabs are
largely Potassium.

>Now mind you,  I am no scientist.  But I do seek the truth here.  And I
>there is room for exploration.   

That's what science is all about.
Just keep careful notes, document changes in plant behaviour and
appearance, etc... and most importantly, report the results (preferably in
an article for TAG <g>) 
>From: sae at arts_ubc.ca (Olga Betts)
>Subject: SAE diet... bit of truth in humour??
>could well be that SAEs DO eat bleached plants more readily because the
>leaves are damaged and they detect the dying tissue. 

Sounds reasonable to me. This is not necessarily a bad thing. Bleached
plants often loose their leaves anyway. Maybe the clean veggies become an
SAE treat <g>. Steve should comment if they also eat his new growth. Of
course once the SAEs learn that the plant tastes good, they may go after
the buds. So, a control is needed with other SAEs.
>>From: "Christopher Coleman" <christopher.coleman at worldnet_att.net>
>>Subject: Re: Algae Sequestering of Nutrients
>>First, welcome back Frank,  I have miss your posts.
>I second That!

For the newbies to the APD on board, "Frank" and "Neil" are the same person


>From: "Ray Pollett" <rpollett at nas_com>
>Subject: Re: mulitple areas

>>[Karen}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.
>I've used them for the last 5 years without green water. I find that a
>little two covenient to totally lay the blame for green water at their feet.

Every situation is different. For example, some people run successful tanks
with high N and P levels with minimal algae (they limit the Fe
concentration in the water colum). Others have enough heavy plant feeders
or fast growing plants that quickly suck up the nutrients and keep the
leached chemicals away from algae.  DAI tablets won't always cause an algae
or green water problem. But it can and it does. I have experienced it myself. 

>They may have been the straw that pushed the tank out of balance, but that
>is only possible if there is P present from other sources.

Most people keep fish with their plants. P comes from fish food.

A common strategy (one of many) to avoid algae is to limit P in the water
column. This is not to say to eliminate it from the tank. It is probably
sitting in most substrates (with laterite, soil or just plain mulm)

 Some algea in a tank is good. Fry get a good
>source of food in the algea areas. A nice light green mat covering driftwood
>is very attractive in my opinion. Some of the fish we keep need it in their

I agree. I too like to have algae in certain tanks...  Let's say: "algae in
a tank _can_ be good." 

If I am in any "camp," I am in the one that prefers not to have epiphytic
algae in a planted tank. [Epiphytic means attached to plants or other algae.]
>I keep one tank constantly for years loaded with BBA over everthing. Best
>Fry growout tank I ever keep. Wish I had it now for my cory fry.

If you like, I can send you some nice Java Fern with great BBA from my
"special" tank. 

>From: krombhol at teclink_net (Paul Krombholz)
>Subject: Re:snails carrying algae

> Does the "aquarist" tolerate ick, velvet, and other fish diseases in 
> his or her tank and merely try to keep them in check?

Gee. I wish I thought of that line!!