# Potassium & Magnesium Deficiency



## Darksome

In my ten gallon tank I suspect I have potassium and magnesium deficiency...at first I noticed it with my java ferns, the leaves started getting black spots and then turned into holes...then this morning I noticed small holes on the bottom older leaves of my ludwigia which are also turning yellow. What is the easiest way to rectify the problem? I have some epsom salt (magnesium sulphate) if I can use that, how much do I use? I also dose 5ml of Leaf Zone once a week after the weekly water change....this seems to have small traces of potassium, should I just wait it out and see if it helps? When one refers to potassium as a plant nutrient, does potassium iodide count as one of them? I found a salt at the store that contains potassium iodide+calcium...not sure if this might help. 

Thanks.


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## Seattle_Aquarist

Hi Darksome,

Here is some information on your magnesium question. Mg2SO4*7H2O (Epsom Salts) = ½ teaspoon (2.7 grams) will add 7.03 ppm of Magnesium to 10 gallons of water. * Suggested Mg levels are 5-10 ppm

I'm sorry, I'm not able to help you on the Potassium question.


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## Philosophos

Iodine is specifically why people don't use table salt for brine shrimp or SW tanks. I don't know much about it's toxicity, but I doubt it would be a good first choice. Combinations of KNO3, K2SO4 and KH2PO4 are more typical. KNO3 shouldn't be too hard to track down.

-Philosophos


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## Darksome

Thanks Seattle Aquarist.

Philosophos the only reason I asked is because I can't seem to find any of these locally and my closest hardware/garden stores are miles away...but I'll look into it and see if I can find any of that...I'm just trying to find any derivatives that might be of use, I've also heard of Potassium chloride, which is the easiest thing I can acquire at the moment...will this do? I know the chloride might be a problem :X Thank you.


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## Zapins

Java fern routinely develops black leaves with decay. It is a natural part of this plant's life cycle. Usually the black leaves will be covered with baby java ferns. The plant kills the leaf so the babies can float away and establish new colonies of java fern.

As for the holes in the ludwigia, it could be a number of things. It might not even be a deficiency at all. A good close up picture of the plant would be extremely helpful, as would a more detailed description of the problem. How big are the holes? Is the entire plant going yellow or just old growth? Are the older leaves being shaded and not getting enough light?

Magnesium deficiency is usually characterized by bright green veins but the tissue between veins is yellow or dying. Calcium deficiency is usually seen in new growth where the tips curl and look twisted, there can also be a bit of yellowing in the new growth. Potassium deficiency shows up as pinholes in older leaves that enlarge over time. 

I doubt you have any deficiency at all, most likely the plants are being shaded and are dying off under the light zone - then snails and fish munch on the dying old leaves. Again a picture is essential.


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## ray-the-pilot

I agree with Zapins and you probably don't have any defficiency problems but it is hard to say. 
My suggestion is that you find a program like PPS, EI or a comercial program and just flat out stick to it. It is beyond the ability of most people to come up with a new program that doesn't lead to problems. 

Forget trying to find some local substitute. Just go to the internet and buy the chemicals you need. That way you don't have to worry about all those what ifs and you don't have to worry about deficiencies.


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## Darksome

It might be a deficiency of some kind...the thing with the java ferns is that they don't develop small java ferns as they usually do, the leaves just darken and wilt away...I have to cut the ones that are decaying because they soon turn into mush. And with the ludwigia it isn't shaded at all, it is well under the bulb with the highest intensity (note:I recently added a second bulb over this tank and that's when the ludwigia started growing 2.8 wpg)...what puzzles me the most is that these holes appeared in a matter of two days...the bottom leaves on the ludwigia are yellowing in addition to small brownish black holes slowly consuming a whole leaf. I first thought it must had been a hungry fish when it had happened to the hygrophila polysperma...but the holes start out too small to be caused by any fish and the snails certainly didn't do it, they are MTS...not known for their plant eating habits. 

ray-the-pilot...I wish the internet was an option...I don't have a CC or Paypal so basically I have to rely on local stores to carry what I need. Are any of these things at Home Depot?

Anyway here are some pics.
(1)hygrophila polysperma (2)ludwigia repens (3-5) java fern


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## ray-the-pilot

The way the plants are attacked leaving the "not so tender" veins makes me believe this could be a fish or snail. What kind of fish do you have?

If you have a local fish store (LFS) or a pond supply store nearby, they will order things for you. I've found that my LFS can get me stuff cheaper that I can get it on the internet. You may have to prepay.

Seriously, it is difficult to diagnose a plant problem when you are not following a program. It is just "fool arround" with different variable until your plants get better or your tank turns green and you give up. 

Also, if things were great before you changed something why not just go back to where you were?


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## Zapins

Looks like it might be a slight potassium deficiency on the ludwigia. The hygro is being eaten by something. Lots of fish love eating this plant in particular, especially plecos, barbs, larger tetras, etc...

The java fern looks normal to me. Sometimes they produce black leaves, it isn't a good plant to watch to spot deficiency symptoms in general. 

Some K2SO4 (potassium sulfate) should do the trick. You might also be able to get the potassium from adding potassium nitrate (KNO3) or from potassium phosphate (K2PO4). They sell some of these in pharmacies or at garden shops. You also might want to post a "wanted" add in the for sale and trade section of this site and see if someone can send you some for money in the mail.

I think the best thing to do would just be sign up for paypal. It is a trusted and safe company used by tens of millions of people, just be cautious of who you are paying, make sure they are trustworthy and will actually send you the items you paid for (check their feedback). Times change, and in today's world business online is routine and relatively safe if you do your research.


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## Darksome

In this tank I have black neons and glowlights...and MTS snails...I've never seen them nip on any of the plants...it's a recent phenomenon...this tank, with the same fish, has been up for well over a year. I'll probably have to do some experimenting or just wait it out. The only thing I've changed recently was the addition of a second bulb, even so the ludwigia started growing, when before it was just there...thanks


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## Zapins

Often times nutrient deficiencies or nutrient deprivation causes the plant to become stressed and be more vulnerable to being eaten. Additionally, if you look at the picture the hygro is missing a piece at the tip of the leaf. This is not normal deficiency signs. The plant absorbs the leaf it doesn't cut pieces of it out like that. I bet the MTS are munching on it at night when the lights are off and they come out to scavenge.


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