# Can Ca(NO3)3 be harmful ?



## kekon (Aug 1, 2005)

Despite lowering K+ levels down to max. 10 ppm I still notice tips burning and stunting. Situation is better than before (when I had over 20 ppm of K+) but the problem with tips burning and stunting still exists. In order to control K level I dose it only at WC (10 ppm K given into changed water from KNO3) and I dose 2.5 ppm of NO3 daily from Ca(NO3)2. I increased Ca up to 32 ppm and Mg to 7 ppm (approximately) but it didn't help much. I know Edward wrote about Ca(NO3)2 and he had issues with some species that died from dosing. It seems it may be certain harmful factor in my tank water but I haven't managed to find it for 3 months. Do you think Ca(NO3)2 can cause issues ?

NO3: 10
PO4 1..1.5
K: about 10
Ca: 32
Mg: 6..7
Na: 4
Cl: 5
KH: 3
pH: 6.6-6.8

TMG, 4ml daily. Tank 200 liters, 150W fluorescent bulbs: 3 x 4000K, 2 x 6000K

To make my KH I let RO water to flow through a cartridge filled with CaCO3 in a gravel form (used for saltwater tanks as a source of Ca) and it gives me 
KH = 2. Next, I add some NaHCO3 in order to achieve KH=3.


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## Zapins (Jul 28, 2004)

K is not a harmful element, or ion. I have levels over 200 ppm in all my tanks and there are no burning incidents in any of my plants. In fact, potassium is one of the nutrients that is nearly impossible to overdose on. Symptoms of potassium deficiency are when small pinholes appear in the leaf (across the blade) and then the holes widen and the entire leaf dies. Do not skimp on your potassium levels it is a vital nutrient.

Can you describe the burned leaf tips more? Where are they burned exactly, how do the leaf veins look/what color, what color are the affected leaves. How does the burning progress, if at all? Good close up pics would help. But... just by what you have said i would suspect that your plants are phosphate limited since phosphate deficiency symptoms are exactly what you have said. Necrosis of the leaf tip is the first sign, then as the deficiency continues, the leaf begins to die or "burn" inwards to the base of the leaf. Also stunting of growth is a symptom of phosphate deficiency. I would recheck your phosphate levels with a known amount of phosphate in a container or pure water (distilled or RO) to test the accuracy of your test kit. 

Not 100% sure about the Ca(No3)2 being harmful, but from what i know about chemistry and plants i wouldn’t have thought it was harmful since it just dissociates into Ca+ and 2NO3- ions which are both plant nutrients. Not sure what Edward meant with his post, i didn’t read it.


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## kekon (Aug 1, 2005)

Take a look at photos:

http://www.aquaticplantcentral.com/...zing/16377-my-plants-still-wrow-deformed.html

Those symptomps appear always after adding K. This is not PO4 deficiency as I have over 1ppm PO4 nor NO3. Water parameters are as given above so I don't lack of any macro nutrient. Actually I had pinholes when K was very low but there is no longer K deficiency. Such plants as Glossostigma, Cabomba, Zosterifolia, Blyxa Japonica, Microsorium, Anubias, Cardamine Lyrata grow quite well apart from Alternatera, Rotala Rotundifolia and Umbrosum. Umbrosum is the most affected plant. When I had 27 ppm K, two Alternatera even died. The very interesting thing is that I never had any issues when used commercial NPK fert that consisited N in urea form and - as producer declared - biostymulators. Problems began after switching to KNO3, KH2PO4 and Ca(NO3)2. A friend of mine has similar issues ("tips burning"). There is no necrosis nor chlorosis. I got severe tips burning, leafs twisting and the overall growth is also stunted.


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## Zapins (Jul 28, 2004)

First of all, as i have already stated above K (potassium) does not harm things in the tank even in ridiculously high concentrations. In fact, severe plant deficiencies will happen if you barely scrape the minimum range like you are at 5ppm. Rather then looking at fertilizers that are well used, and trusted as being poisonous to your plants why not look at what is missing from your tank, after all you are using RO water.

Plants take a long time to show deficiencies, and it may take longer for one species to show a deficiency then another species. So obviously, the plants that grow the fastest in your tank will show the deficiency first, and then a few weeks or days later the rest will too.

Before continuing, how are you testing your water parameters? Are you just calculating how much is in the tank by what you add? Or are you actually doing titration tests. In addition, have you done these tests recently or was it weeks ago that you tested? Calculating how much of a fertilizer is in your tank by numbers and what you add is not accurate at all. Plant deficiency symptoms do not lie, but calculated tests (and even titration tests to a lesser extent) can be significantly wrong. 

I read through your other thread and looked at the pictures. I see no leaf burning. What i see are the leaves twisting and turning as if they have been pinched as they grow out. This is a completely different cause then "leaf burning and stunting." In fact, i have no idea what you mean by "severe tips burning," because to me and everyone else on the forum it means necrosis and chlorosis. 

The twisting leaves i see in your photos are not from some sort of toxic effect from the chemicals you are adding. They are much more likely to come from a problem with calcium and magnesium ratio. Plants like a 4:1 calcium:magnesium ratio and begin to exhibit weird growth in new leaves like i see in your plants. 

For your knowledge:
Calcium deficiency is characterized by some of the following symptoms (not necessarily all): newly formed roots will not grow properly, young leaves will curl and twist, the plant will be stunted and have yellowish patches or spots.
Magnesium deficiency: occurs in old leaves and symptoms do not appear until the deficiency is advanced. Plant will be stunted, but leaf veins will stay green while the rest of the leaf will turn yellow. Brown spots will appear and the plant will begin to die.
Potassium deficiency: occurs in old leaves only, in early stages the older leaves will begin to curl and the become blotchy and scorched. Stems will be soft and more squishy.
Phosphorous deficiency: New leaves will be stunted, sometimes the leaves will be discolored, the stems will be harder then normal, the root systems will be poor and have very little branching. The first signs of this will appear in older mature leaves.

Most of the other deficiencies have symptoms where discoloration or holes/necrosis appear on the leaf, not at the tips. So we can discount all of these right off the bat.

So, after seeing all the possible deficiencies that i have listed, what looks the most likely to you?


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## kekon (Aug 1, 2005)

When it comes to Ca, it's not deficiency as my GH test shows GH = 9. I reconstitute RO water by adding 30 ppm Ca and 7 ppm Mg each week at 50% water changes. Additional Ca comes from Ca(NO3)2 and some from CaCO3.
I know what plant deficiencies look like I can frankly say that it is no Ca, Mg, P, N, Fe etc. Take into account the fact that all the issuses shown in the photos began after stopping to use NPK fert -with N in urea form - to KNO3 and Ca(NO3)2 and KH2PO4. Those days I had only 13 ppm Ca and 4 ppm Mg and didn't have any deficiences. Plants grew like crazy. I had also 0.1 ppm PO4 and 2.5 ppm NO3. Maybe it's a matter of Ca/Mg/K ratio. Do you remember Edward's experiment with Rotala Wallichi ? This plant didn't grow well at Ca = 20 and Mg = 10 but grew very well when Ca = 20 and Mg = 2 (Ca/Mg = 10) Maybe my Mg is too high ? I dose just 7 ppm Mg into the changed water. I can't use tap water as it consists 20 ppm NO3. 
There are also some concerns about lighting wavelength... My acquaintance said he had got stunted tips after changing 4000K bulbs to 6000K ones.


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## Zapins (Jul 28, 2004)

Odd. That the Gh is 9, do you have a calcium test so that you can tell how much is Ca and what is Mg?

But from what i saw in your pics i didnt see any obvious deficiencies except possibly in the middle pic. Can you post some new pics where it is easier to see the problem?


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## kekon (Aug 1, 2005)

I will take some new photos and post them here in a few hours (I'm currently at work so I can't do it now). But I can tell that most of new plant tips look exactly like in the middle picture. The more K+ the more such tips I get. Anyway, what can you say about the first pic ?


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## kekon (Aug 1, 2005)

Here I post new pics. You can see deformed leafs and wahat I call "tips burning" (which means that they looke as if they were burned with a lighter). The next thing I'm going to do is to have only 4ppm of Mg.


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## Zapins (Jul 28, 2004)

Interesting pics. It looks like the leaves are curled and stunted. 

The only thing i can think of before going further and looking at nutrient blocking is that perhaps the tests are not correct. For example, you say you have 32 ppm Ca and 6 or 7 ppm Mg but your general hardness says you have 9 degrees hardness which i believe is more then you calculated. If you can do a hardness test on known amounts of Ca/Mg to determine how accurate it is that will help greatly. 

Seeing more photos of your plants with curled, hooked leaf tips looks even more like calcium deficiency to me. There may be a few different causes for this. One is that the tests are simply incorrect and the other is the whole blocking/uptake business. It is possible that there is too much magnesium in your water which blocks the uptake of calcium thus causing calcium deficiency.

It might be helpful to try changing the Mg/Ca ratio but before you lower your already low Mg levels i would consider 2 things.

One: determine the real levels of nutrients in your water first by buying a calcium test and calibrating the Gh test. This is the best thing to do before changing tank parameters.

Two: raise the calcium level to a known amount say... 60ppm in addition to whatever you have in your tank already. If it was the Mg/Ca ratio blocking the uptake of calcium then the deficiency should disappear as the Ca is definitely more concentrated then the Mg level. The nice thing about this is that even if the problem is more complex then you have not really hurt the tank by adding more calcium (as long as its not the Ca(NO3)2 that raises the calcium, rather add CaCl2). Hard water is actually better to grow most plants in rather then soft water. 

In addition, if you lower the Mg ratio to ~4ppm you are working with extremely small numbers here, the smaller your ppm #s are the more likely it is that something will go wrong because you have less to start out with. You might run into Mg deficiencies as well. 

As far as the K goes... in terrestrial plants K is usually kept in a 1:1 ratio with nitrogen. However, in the plant tanks it is usually dosed to around 1:5 ratio Nitrogenotassium so you should probably increase your K levels a little it won’t hurt your plants.


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