# water too soft? not enough iron? Amazon sword brown spots



## sammy (Jun 21, 2006)

Hi,

I have a El Natural 55G tank, and the amazon swords I put in there don't seem to do well (brown spots.. see attached). My tap water measures 0 dH of GH and 0dH of kH, so I regularly add NaHCO3 to the tank and also have oyster grit in my filter. The tank water now has 4~5 dH of kH and 1~2 dH of GH.

I phoned my fish store and asked about this issue and they told me this was a sign of iron deficiency. I wasn't able to verify this because I don't have iron test kit. 

Are the brown spots result of water being too soft, or are they real signs of iron deficiency? Also, how come the oyster grits I put in the filter don't work well? It hardly raise GH or kH, so I have to keep adding NaHCO3 to the tank.


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## Minipol (Jul 4, 2006)

I'm not sure but it looks more like iron toxicity to me.
As i said, no expert here so better wait for some other advice on what it is.

When you have soft water, heavy metals are more readily released into the water. 1-2 GH is still very soft water.
In any case, if it's iron toxicity or deficiency, you would need to get the GH higher.


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## sammy (Jun 21, 2006)

thanks for your reply. I re-read Diana's book on metal toxicity (page 13-14) and it seems you are correct. Faster growing plants are not affected by this and only Amazon sword which does better in hardwater than software gets affected.

I will raise the GH immediately. *Any thoughts on how to do it efficiently the natural way?* Oyster grits don't seem to work well for me at all. I have a big filter (not much bio filter media, mostly mechanical filtration foam), and I have a compartment full of oyster grits. My pH is around 7.0-7.4 (result of addition of NaHCO3), which is too alkaline to dissolve CaCO3 efficiently I guess. I tried Ca and Mg supplements for human consumption and they do not work either. *Or should I just wait for the kH to be used up naturally* (very fast in my tank -> probably because of the Jungle Val. I can see 2-3 dH decrease in one day) *so that the water begins to dissolve the oyster grits?*


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## dwalstad (Apr 14, 2006)

Hello Sammy,

In the AB archives we discussed the problems with oyster shells not dissolving fast enough to address a problem like yours or bringing the pH up when it does.

The conclusion was that adding a mixture of calcium chloride and magnesium sulfate (4:1) was probably the ideal way to fix the softwater/low calcium problem. You can order calcium chloride from beer brewers or as a de-icer. Calcium chloride, unlike calcium carbonate, dissolves immediately and doesn't raise the pH. 

You could also use the Equilibrium product sold by SeaChem. Unfortunately,this product contains a lot of sulfates, so it might cause long-term problems in a tanks with fresh potting soil. However, right now you need to get that GH up to 4-8 fast-- before your swordplants disintegrate.

The only "natural" way would be to dissolve the shells in weak hydrochloric acid before adding. However, this requires working with a dangerous acid and careful pH monitoring.

I would go with buying calcium chloride.


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## sammy (Jun 21, 2006)

Hi Diana,

Thanks for the reply. I already bought Equilibrium 2 days ago and gradually raised the GH to 5. I also bought iron test kit and found no detectable free iron and about 0.1 ppm of chelated iron in the water. I have some phosphate in the water and I think phosphate binds iron fast and my tank shouldnt have any iron toxicity.

About Equilibrium: The tank in my picture is not using ordinary soil as substrate. I use *Flora Base* in this 55G tank. I think Equilibrium should be ok with this substrate? I am setting up a new 90G tank with *garden soil
* and I think it is also ok to use Equilibrium with it (page 133)? Why is adding CaCl2 + MgSO4 ok but adding Eq. is not *since MgSO4 contains sulfate too? *How do I measure H2S in the water?
Another plant question: my *densa *seemed to turn transparent the past few days while all other plants are doing ok.. It has been very hot past few days including today and the tank temp was as high as 86F. Is high temp the cause of this problem? I add lots of ice but the effect was minimal.

Thanks again for your reply, Diana.


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## dwalstad (Apr 14, 2006)

sammy said:


> Hi Diana,
> 
> Thanks for the reply. I already bought Equilibrium 2 days ago and gradually raised the GH to 5. I also bought iron test kit and found no detectable free iron and about 0.1 ppm of chelated iron in the water. I have some phosphate in the water and I think phosphate binds iron fast and my tank shouldnt have any iron toxicity.
> 
> ...


The calcium chloride dosing procedure I describe contains mostly chloride. The sulfate is a minor ingredient.

I don't know of any products to measure H2S. I would gauge it by blackened roots or a rotten egg smell coming from substrate.

E. densa is a hardwater plant. The softwater could turn this plant into a yellow mush.


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## sammy (Jun 21, 2006)

e. densa is back to life now. I guess Equilibrium works well for me. I have GH set to 5, and densa turned green just today.

Where can I find info about hardwater plants and softwater plants? I want to have a better idea and a reference next time things like this happen.


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## dwalstad (Apr 14, 2006)

In my book, I discuss this important concept (pp 112-118. 

It's not just nutritional needs but susceptibility to metal toxicity that separates hardwater plants from softwater plants. That is, hardwater plants like Elodea and Val are going to be much more susceptible to metal toxicity. In softwater aquariums, they will be the first plants to turn yellow and then disintegrate. Calcium ameliorates metal toxicity for these plants.

In general, plants found in naturally hardwaters (Val, Elodea, hornwort, Cryptocoryne balansae, etc) are hardwater plants.


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