First time dosing K for pinholes, advice on amt? - The Planted Tank Forum
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post #1 of 7 (permalink) Old 11-21-2015, 02:27 AM Thread Starter
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First time dosing K for pinholes, advice on amt?

I could use a little help with where to start when dosing K in my aquarium. I have used the Fertilator, I have adjusted EI...and have had horrible problems with my only high-ish tech tank for years. I finally started testing more instead of assuming/adjusting, and my current dosing is very far off from what EI recommends, despite the fact that my tap starts me at 0 for KN03/P04 (yes, I calibrated my kit). For the first time in a long time my plants are looking much better, but I am having the typical pinhole problems with my H. Pinnatifida, which I read is a Potassium hog. I would like to start adding Nu-Salt and increase as needed, but I’m not sure how much to start with for a 20g.

20g tall
T5 48w
pressurized CO2
gh/kh: both 4
I add (all x 3):
3/4 tsp KN03
1/64 KH2P04
1/32 CSM+B

Compared to EI guide:
10- 20 Gallon Aquariums
+/- 1/8 tsp KN03 (N) 3x a week
+/- 1/32 tsp KH2P04 (P) 3x a week
+/- 1/32 tsp (2ml) Trace Elements 3x a week

This results in 20ppm Nitrate and 2ppm Phosphate. Seems like the KN03 should be crazy high, P04 super low, but like I said, the plants are doing much better.

I realize the ppm for the Nitrate isn’t considered high, but the amt I am already adding does seem like a I would like to add some K. I do realize that I shouldn’t have a problem with dosing a lot of K, but where should I start? Does 1/2 tsp x 3 sound like too much? Fertilator doesn’t tell me it will be obscenely high at that amt, but program hasn’t been working for me anyways. I should add that the current H. pinnatifida is newer plant. The pinholes are coming after the higher KN03 dosage started. But I did have it to a higher degree when I had it in the past before the higher dosage. I believe it is a K issue. It’s not too bad yet, but I have lost this plant to this problem before.

And because everyone wants a terrible pic :

Last edited by skelley; 11-21-2015 at 02:45 AM. Reason: remove PB acct info
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post #2 of 7 (permalink) Old 11-21-2015, 02:49 AM
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It's not a potassium deficiency. It's a micronutrient toxicity. Dosing more potassium won't help. However, ceasing CSM+B dosing will.
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post #3 of 7 (permalink) Old 11-21-2015, 03:04 AM
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Never heard anyone say their pinnatifida took up that much K before.
Do you know if more of your plants fit that hog label ?
For a planted tank your nitrates seem to be a good level.
If you look on this list at the dry dose part for any of the tanks it list
K2SO4 as an optional. That is what I'd add if I were going to try to get
more K. It won't add more nitrates.

And I'd start/w 1/8 tsp of it added to what you are already using.
Meanwhile check/w others on here especially Zorfox, about the possibility of excess K
in this whole issue. toxic level yea/nea

Bump: There is that possibility that Solcielo lawrencia is on to the right track.
If you wish to try what he said before adding more K that may be a good
idea based on your already being over what is normal on the K.
But...just as I suggested using small jumps for the K, I'd just cut the
CSM+B in half at first...just to see if...

The shortest distance between any two points is a straight the opposite direction...
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post #4 of 7 (permalink) Old 11-21-2015, 04:10 AM
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From what i've seen with my Pinnatfida, that does not look like the holes when I had micro tox. When I had too many traces, the holes were much smaller, and much more numerous. This might actually be K+ deficiency if I looked at it in my tank.

It's hard to tell. As soon as I backed off the traces in my tank almost a year ago, the Pinnatfida took off. First I'd try a little more K+. If you don't have a gram scale, I'd dose 1/16th tsp three times a week, and if that doesn't cure it in a few weeks, it's not K deficiency. At that point, i'd move to backing off the CSM+B and substituting some of it with DTPA iron.

I also think K+ deficiency for some plants, especially small leafed plants look quite different. I've noticed total yellowing of the leaf (both older and new growth) which was attributed to not enough K+. As opposed to iron or mag deficiency which is usually chlorosis between the veins of the leaf. In very severe iron deficiency the leaf can turn totally yellow, but I think it's very rare if you are dosing at least some type of Fe. Nitrogen deficiency looks like total yellowing of the leaf, but new growth is also very small and the bottom leaves start to turn transparent.

EDIT: Upon closer examination of the picture, and looking at the healthier green leaf, I'm now swinging towards a micro tox. The leaves curling in on itself like that is usually Ca++ shutoff from heavy metal crowding. Yeah, I'd dose NO traces for a few weeks. Do an immediate water change of 80%. If you do dose a micro, make sure it's only iron and not more than .1 ppm a week.

Also, that AR has classic tox signs. Of course make sure your CO2 is good.
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post #5 of 7 (permalink) Old 11-21-2015, 04:17 AM
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Positron, it's likely that the micro-tox is a bit more severe than in your case. If you look at the pictures in the "H. pinnatifida how much potassium" thread, you'll see just how bad toxicity can induce a K deficiency. Necrosis can also occur which results in the leaf falling off.

Also note, excess K+ helps prevent micro-tox by crowding the metal cations out. The same occurs with with Ca and Mg, which is even more effective due to their double + charge. However, this does not reduce the concentration of the metal cations, just limits their toxic effects.

Also, if you look at the pinnate lobes in the OP, the lobes are curling downward, which is another sign of micro-tox.
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post #6 of 7 (permalink) Old 11-21-2015, 04:30 AM Thread Starter
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I highly doubt that I am getting a micro toxicity at that dosage. What gives you that idea? My needs for this aquarium seems strange, so I can't rule it out. I haven't found any literature about micro toxicity that matches these symptoms.

Here are just a couple threads of many about K with this plant:
Many holes in Hygrophila pinnatifida - Plant Deficiencies - Aquatic Plant Central

ETA: Positron, that post is very helpful, thank you!
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post #7 of 7 (permalink) Old 11-21-2015, 04:33 AM
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It's an induced deficiency.
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