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Old 14-10-2004, 03:02 AM
Dances With Ferrets
 
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Default Yet another potassium question....

Heya folks... anyone got any ideas for cheap sources of bioavailable
potassium for a heavily-planted 50-gallon tank, along with approximate
recommended doseage? Someone told me potassium permanganate, but I
have serious doubts about this.

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Old 14-10-2004, 03:25 AM
Bill Stock
 
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"Dances With Ferrets" wrote in message
om...
Heya folks... anyone got any ideas for cheap sources of bioavailable
potassium for a heavily-planted 50-gallon tank, along with approximate
recommended doseage? Someone told me potassium permanganate, but I
have serious doubts about this.


I use Potash, aka Muriate of Potash or 0,0,60 fertilizer. I think it's also
sold as salt substitute and road deicer. Watch out for other additives
though. Mine came from the garden centre.

I use it in the pond at 2 tsps per 500 gallons, so my 5 lb bag should do me
a lifetime.



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Old 14-10-2004, 11:19 PM
Michi Henning
 
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Default

"Dances With Ferrets" wrote in message
om...
Heya folks... anyone got any ideas for cheap sources of bioavailable
potassium for a heavily-planted 50-gallon tank, along with approximate
recommended doseage? Someone told me potassium permanganate, but I
have serious doubts about this.


Potassium permanganate is a strong oxidizer and not suitable. I'd suggest
Potassium nitrate (KNO3), which you can get at any hydroponics store.
Dissolve 162g of the salt in 1 litre of water. 1ml of the resulting stock
solution
will raise the NO3 level of 100 litres of water by 1ppm. If your tank is
heavily planted, chances are that you will have to supplement nitrate anyway,
and the plants appreciate both the nitrate and the potassium.

If you need to dose phosphates as well, try potassium dihydrogen phosphate
(KH2PO4). You can also get it at hydroponics stores or at laboratory supply
shops. Dissolve 14.2g of the salt in 1 litre of water. 1ml of the resulting
stock
solution will raise the PO4 level of 100 litres of water by 0.1ppm. (If you
are having trouble weighing 14.2g, ask a friendly pharmacist for help, or
make it 142g into 1 litre of water. The take 100 ml of this high-concentration
solution and top it up to 1 litre, and you now have the 14.2g stock solution.)

Shoot for around 8-10 ppm of nitrates and 0.3-0.4 ppm of phosphates in
your tank, and watch the plants take off :-)

BTW -- someone recently posted a useful link for dosing nitrates and
phosphates. Here it is once mo

http://www.xs4all.nl/~buddendo/aquarium/redfield.htm

That's a nice tool to use after a water change when you need to work out
how much nitrate and phosphate to add in order to replace the removed
nutrients.

Cheers,

Michi.

--
Michi Henning Ph: +61 4 1118-2700
ZeroC, Inc. http://www.zeroc.com



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Old 15-10-2004, 04:23 AM
[email protected]
 
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http://www.xs4all.nl/~buddendo/aquarium/redfield.htm

That's a nice tool to use after a water change when you need to work out
how much nitrate and phosphate to add in order to replace the removed
nutrients.

Cheers,

Michi.


Aquatic macrophytes are not marine phytoplankton which is what the
Refield ratio is based on. the avwerage of most submersed plants is
10:1m, not 16:1.
It also wrongly assumes BGA will be caused and cured within pretty
narrow ranges for NO3 and PO4.

I can assure you that I can have a 2ppm of PO4 and 5ppm of NO3 and
never get BGA outbreaks. Likewise I can have a .2ppm of PO4 and a NO3
of 20 and never get any.

BGA will appear if you drop the NO3 levels down very low and slow the
plants uptake(perhaps of NH4 and thereby allowing the BGA an easy
meal, they do not need hardly any N relative to plants)
The reference is also not for FW, but rather phytoplankton. While I
cannot read German/Dutch, I can tell from the names and it appears
that they did not add plants to these experiments, only algae.

They also assume that BGA, in this case Oscillitoria can fix N2 gas
from the air, not true unless they have heterocyst. No heterocyst, no
N2 fixing in this genus. I've never found any heterocyst in dozens of
smaples sent from all over(everyone has this genus)and I also see no
reason for them to be limited EVER in a FW planted tank, their needs
are extremely small relative to the plants and they exist in a
different niche. No hobbyist possesses the needed test procedures or
kits to measure N limitation in this genus, it's in the low ppb range.

Plants are a huge influence in terms of algae and phytoplankton, I
did not see that plants were added in the reference anywhere. That is
a key element if you want to argue this point.

While their "good" range will work, their reasoning has some issues
and the assumptions are large and the observations I've done over the
years don't not show any signs of BGA nor could I ever confirm their
conclusions/observatuions regarding their ratios and BGA
outbreaks/presence.

Add some KNO3 at 1/4 teaspoon per 20 gals 2x a week if you use CO2 or
more depending on lighting/fish load. That alone will keep it away.
See APD for older post about BGA and heterocyst.

Regards,
Tom Barr
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Old 16-10-2004, 12:09 AM
Michi Henning
 
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Default

" wrote in message
om...

Aquatic macrophytes are not marine phytoplankton which is what the
Refield ratio is based on. the avwerage of most submersed plants is
10:1m, not 16:1.


Ah, I didn't know that. So, we'd need to shoot for less nitrogen and
more phosphate than this calculator recommends?

It also wrongly assumes BGA will be caused and cured within pretty
narrow ranges for NO3 and PO4.

I can assure you that I can have a 2ppm of PO4 and 5ppm of NO3 and
never get BGA outbreaks. Likewise I can have a .2ppm of PO4 and a NO3
of 20 and never get any.


I believe that. Personally, I'm actually more interested in keeping other types
of algae down. Black brush algae (the bane that caused me to tear down
my tank eventually and start again) and, to a lesser extent, beard/staghorn
and green thread algae.

BGA will appear if you drop the NO3 levels down very low and slow the
plants uptake(perhaps of NH4 and thereby allowing the BGA an easy
meal, they do not need hardly any N relative to plants)


Yes, seems that way. The Redfield ratio indicates that high phosphate and
low nitrate favours BGA, and high nitrate and low phosphate favours
green algae. (This agrees with my previous experiences -- I was battling
green algae until I picked up on your recommendation to dose phosphate.
Unfortunately, by the time I saw the truth, it was a bit too late to save the
tank.)

The reference is also not for FW, but rather phytoplankton. While I
cannot read German/Dutch, I can tell from the names and it appears
that they did not add plants to these experiments, only algae.


Me bad -- I posted the wrong link. Here is an English version, which
I'm sure will make a lot more sense to many people :-)

http://www.xs4all.nl/~buddendo/aquar...dfield_eng.htm

Add some KNO3 at 1/4 teaspoon per 20 gals 2x a week if you use CO2 or
more depending on lighting/fish load. That alone will keep it away.
See APD for older post about BGA and heterocyst.


I've just (a week ago) set up the new incarnation of my tank. (150gal nominal,
actual water content 130gal.) I've been following your posts on APD about
whether to fertilize a freshly set up tank and started dosing KH2PO4 and
KNO3 from day one as you recommend. So far, things are looking good.

I've been aiming for around 10ppm NO3 and 0.5ppm PO4. (It's difficult to
be precise with the test kits that are commonly available in Australia -- the
resolution isn't good enough. It turns out that LaMotte have an Australian
distributor though, so I think I'll get the high-resolution LaMotte NO3 and
PO4 kits, so I can control the ratio more precisely.) A very small amount
of green hair algae is currently present in the tank, and a little
beard/staghorn
algae, which I suspect I imported with the plants initially. I've been removing
what I can find of those manually. For the time being, the only fish are a
bunch of Otocinclus Affinis that are not getting any food other than what
they can find for themselves, in the hope that they will stay on top of any
minor algae growth. We shall see... :-)

Cheers,

Michi.

--
Michi Henning Ph: +61 4 1118-2700
ZeroC, Inc. http://www.zeroc.com

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Old 16-10-2004, 09:56 AM
[email protected]
 
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Ah, I didn't know that. So, we'd need to shoot for less nitrogen and
more phosphate than this calculator recommends?


Well does not really matter from a practical standpoint but might be
more convient I suppose. The main thing is not to allow something to
become plant limiting.
You are not going to beat the algae through nutrient limitation, you
can try and you can try.

I believe that. Personally, I'm actually more interested in keeping other types
of algae down. Black brush algae (the bane that caused me to tear down
my tank eventually and start again) and, to a lesser extent, beard/staghorn
and green thread algae.


Ahh well, here's your issue:
CO2.
Directly poor to variations of good to low CO2 levels is a great way
to culture BBA.

Poor CO2 is 90% of all algal issues for folks using CO2 gas.

Keep the CO2 20-30ppm during the entire lighting peroid, check pH at
night(PM) and in the early AM. Make sure the CO2 is good during both
these high/low points.

Yes, seems that way. The Redfield ratio indicates that high phosphate and
low nitrate favours BGA, and high nitrate and low phosphate favours
green algae. (This agrees with my previous experiences -- I was battling
green algae until I picked up on your recommendation to dose phosphate.
Unfortunately, by the time I saw the truth, it was a bit too late to save the
tank.)


Well here's what happened with your tank:
You added PO4, this drove the NO3 uptake rate faster, so the NO23
dropped to zero and the plants growth slowed down significantly. BGA
appeared.

If you had added more PO4 and KNO3, then the BGA would not have
occured.

The ratio in and of itself had nothing to do with it. I'd tell you if
it did, I promise

It was the actual levels(limited NO3)

Me bad -- I posted the wrong link. Here is an English version, which
I'm sure will make a lot more sense to many people :-)

http://www.xs4all.nl/~buddendo/aquar...dfield_eng.htm


No, you did good, the English version is up, but the reference for the
article cited is in German.

Add some KNO3 at 1/4 teaspoon per 20 gals 2x a week if you use CO2 or
more depending on lighting/fish load. That alone will keep it away.
See APD for older post about BGA and heterocyst.


I've just (a week ago) set up the new incarnation of my tank. (150gal nominal,
actual water content 130gal.) I've been following your posts on APD about
whether to fertilize a freshly set up tank and started dosing KH2PO4 and
KNO3 from day one as you recommend. So far, things are looking good.


I'd do this:
COP2, then check it again and again till you go nuts and geel very
comfy with it being 30ppm or so.

Generally in 99.99% of all cases, the CO2 will appear lower than the
actual concentration if there is an errorin testing or some other
acid, stray current in the water.

That is the first order of business anytime you see algae or have a
growth issue with plants.

Poor CO2 will get any and everyone from Amano down to the newbie, to
myself.

I've been aiming for around 10ppm NO3 and 0.5ppm PO4. (It's difficult to
be precise with the test kits that are commonly available in Australia -- the
resolution isn't good enough. It turns out that LaMotte have an Australian
distributor though, so I think I'll get the high-resolution LaMotte NO3 and
PO4 kits, so I can control the ratio more precisely.) A very small amount
of green hair algae is currently present in the tank, and a little
beard/staghorn
algae, which I suspect I imported with the plants initially. I've been removing
what I can find of those manually. For the time being, the only fish are a
bunch of Otocinclus Affinis that are not getting any food other than what
they can find for themselves, in the hope that they will stay on top of any
minor algae growth. We shall see... :-)


You can do the estimative index and not bother testing if you wish, or
you can control it and double check your estimations and find the
rates of uptake.
You can also use the plants themselves as indicators.

Eg Riccia pearling is great for CO2.

I'd do this for your tank:
Trim all the alagae I can, prune, vac off any detritus on the gravel
surface etc,l net out any left overs.
Fluff the plants good.

Then do a 50-70% water change.

Add the macros back:
1.5 teaspoons of KNO3
1/8+ teaspoon of KH2PO4

The following day: 30mls of traces

Continue this routine till your 7 th day and repeat.

Dose the macros and traces every other day alternating.

If you have moderate or lower light, you can do about 25-50% less
dosing.

But the levels I suggested will be certain to address any non limiting
needs you might have at any light level.

Biggest issue for now: CO2.

Regards,
Tom Barr

Cheers,

Michi.

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Old 17-10-2004, 12:04 AM
Michi Henning
 
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Default

" wrote in message
om...

You are not going to beat the algae through nutrient limitation, you
can try and you can try.


Yes. You are preaching to the converted :-) By the time that nutrients
are so low that algae won't grow anymore, the plants will be long dead
and, in the process of decaying, produce more nutrients for the algae ;-)

Black brush algae (the bane that caused me to tear down
my tank eventually and start again) and, to a lesser extent, beard/staghorn
and green thread algae.


Ahh well, here's your issue:
CO2.
Directly poor to variations of good to low CO2 levels is a great way
to culture BBA.

Poor CO2 is 90% of all algal issues for folks using CO2 gas.


I can believe that. I had ongoing problems with my CO2 system
(leaks, stuck needle valve, losing calibration on the probe, etc.) So,
when it came to widely fluctuating CO2 levels, I was your man.
I've since replaced the CO2 system with something decent, so that
part of the equation is well and truly under control now. (BTW, if anyone
is looking to buy a CO2 system, stay clear of the Eheim one -- it's
rubbish.)

Keep the CO2 20-30ppm during the entire lighting peroid, check pH at
night(PM) and in the early AM. Make sure the CO2 is good during both
these high/low points.


I have 4 degrees KH, and the CO2 system is set to a pH of 6.8. The
hysteresis on the controller is 0.1 degrees, so the actual value fluctuates
between 6.75 and 6.85. (The manufacturer says that the probe is accurate
to 0.01 degrees after calibration.) Looking at the CO2 chart at
http://www.thekrib.com/Plants/CO2/kh-ph-co2-chart.html, I guess I could
change the set point down to 6.75 without getting more than 30ppm. I might
just do that. (In fact, I'll do just about anything to keep BBA away...)

Yes, seems that way. The Redfield ratio indicates that high phosphate and
low nitrate favours BGA, and high nitrate and low phosphate favours
green algae. (This agrees with my previous experiences -- I was battling
green algae until I picked up on your recommendation to dose phosphate.
Unfortunately, by the time I saw the truth, it was a bit too late to save

the
tank.)


Well here's what happened with your tank:
You added PO4, this drove the NO3 uptake rate faster, so the NO23
dropped to zero and the plants growth slowed down significantly. BGA
appeared.


Actually, no. I kept dosing NO3 as well, and kept it in the 10ppm range.
But, by the time I started that, the brush algae were already too well
established to get rid of again (and I still had the problems with the old
CO2 system).

I've just (a week ago) set up the new incarnation of my tank. (150gal

nominal,
actual water content 130gal.) I've been following your posts on APD about
whether to fertilize a freshly set up tank and started dosing KH2PO4 and
KNO3 from day one as you recommend. So far, things are looking good.


I'd do this:
COP2, then check it again and again till you go nuts and geel very
comfy with it being 30ppm or so.

Generally in 99.99% of all cases, the CO2 will appear lower than the
actual concentration if there is an errorin testing or some other
acid, stray current in the water.


Well, I can determine KH to an accuracy of +-0.5 degrees, and I can
determine pH to an accuracy of +-0.01 degrees, so the error in CO2
levels is fairly small. I can certainly keep it in the 25-30ppm range
with confidence.

That is the first order of business anytime you see algae or have a
growth issue with plants.

Poor CO2 will get any and everyone from Amano down to the newbie, to
myself.


Well, my previous experiences seem to confirm this, so I will take your word
as the gospel on the matter ;-)

You can do the estimative index and not bother testing if you wish, or
you can control it and double check your estimations and find the
rates of uptake.
You can also use the plants themselves as indicators.

Eg Riccia pearling is great for CO2.


Right now, the phosphate is disappearing about as quickly as
I pour it in. Over four days, level dropped from 0.5ppm to
below 0.1ppm.just barely detectable with my test kit, below
less than 0.1ppm. Nitrate levels seem to be dropping less quickly,
from about 10ppm to about 6ppm over the same period. The
tank can't possibly have cycled yet, having set up for only a week,
so I guess things are still finding their balance. I'll keep measuring
and adjusting NO3 to around 10ppm and PO4 to around 0.5ppm
and see how things shape up (all the while keeping CO2
at 20-30ppm, course ;-)

Dose the macros and traces every other day alternating.


I've been using Duplaplant 24 every day at the suggested dosage.
Would you recommend dosing DP24 only every second day?

If you have moderate or lower light, you can do about 25-50% less
dosing.


No, it's fairly high light -- two 150W metal halides and two 36W
fluorescent tubes, for 10 hours per day. That comes to about
2.8W per gallon.

Biggest issue for now: CO2.


Definitely got it, thanks! :-)

Cheers,

Michi.

--
Michi Henning Ph: +61 4 1118-2700
ZeroC, Inc. http://www.zeroc.com



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