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Potassium deficiency or something else?

kschyff

Member
Joined
29 Jun 2020
Messages
132
Location
Dundee, Scotland
Hi All,
I have a problem with a number of plants (see list below and picture attached) that have appeared in the last 2 days. In fact, it is the same problem in that there are holes in the leaves. Some of the leaves look like they are disintegrating, but they are still green. I would think its a potassium deficiency, but I know there are other reasons why this might be happening. I'm still new to this hobby, hence my post. My tank is a 60p and I am dosing 2ml of APT Complete every day. I can provide more details if required. For now note that the plants that are exhibiting this problem are:
  • Hygrophila Pinnatifida
  • Hygrophila Corymbosa
  • Tripartita (only in the last day)
  • Rotala (only as of this morning in the lower/older leaves)
Its a high tech tank with two Zetlights (about 3200 lumen - I don't have the PAR) and CO2 injection via inline diffuser. The tank is flooded with the CO2 bubbles and this has undergone no changes. In fact, nothing has changed for at least 3 weeks so this is a bit strange and this only appeared 2 days ago. Could this be Amano shrimp chomping on the leaves (13 of them in this tank)?
 

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My tank is a 60p and I am dosing 2ml of APT Complete every day.
So 60p is approx 60litres and comparing APT dosing with EI ( I've used the much respected @ceg4048 'Clives EI dose levels')
1618337066507.png

So you can see APT is a little low in NO3, K, Mg and Fe compared to full EI levels.

Most problems (90%+)with CO2 injected tanks are CO2 related, one of the first signs of CO2 deficiency is holes in leaves from too much light for CO2 levels, CO2 is also a major component in the formation of leaves so also they are carbon deficient they will have weaken leaf structure, a weaken leaf structure will make the leaves more susceptible to being eaten. Amanos are great algae eaters, but they also eat leaves (they do in my tanks).

So the cause could well be multi factorial - I would except CO2 being the major culprit
1. I would check the CO2 levels by doing a pH profile making sure the pH is stable from lights on till CO2 off
2. Dosing some more APT x2 will do no harm (except to the cost of using it), some DIY ferts would be much cheaper
3. Feed you Amanos some aglae pellets, I find here in the UK they love Nettles which have been been in boiling water for 5mins of some red or yellow peepers ( have never used hot ones)
 
Thank you @Zeus. I could do I pH profile, but I don't have a pH pen. Let me start with a ferts change. If I dose x2 APT would the additional PO4 not cause a problem? It would then theoretically be almost double Clive's recommended level. Otherwise I have some DIY ferts I mixed according to the EI article on the forum. Maybe I should just do the latter as my growth has been a bit slower than expected.
 
Well I have mixed the macro solution as per the EI article here on UKAPS. I don't have Fe on its own though.I take it that is included in CSM+B I am using. I do want to ask the following if I am using EI: The use of MgSO4 pushes up the hardness by 3 if dose macros 3 times a week. Is this correct? If so, could I still use a DIY remineralising solution which will further push up the GH? I am asking this as I don't want to elevate my kH at all. I recall a thread from a few days ago that health with hardness, pH and remineralisation (can't find it to link here though).

If its ok to dose additional MgSO4 as part of the remineralisation solution then all I need to buy in theory is CaSO4. I remember you posted a picture of a remineralisation mixture (as per your spreadsheet program) in the thread I am referring to above. In short, I want my water to me a bit more acidic.
 
MgSO4 pushes up the hardness by 3 if dose macros 3 times a week. Is this correct?
No, all depends on the Mg ppm you aim for, adding 5ppm Mg adds 1.14GH, you can dose it x3 week so for your 60L 1.0gram MgSO4(epsom salts) three times a week, or 3.0grams straight after the Water Change (WC).

I dont think its the ferts levels for seral reasons which the plants are telling us
1.If NO3 was low the Hygrophila Pinnatifida would be redder
2. Mg deficiency rare but easy to confuse with Fe deficiency, but no signs of Fe deficiency or Mg deficiency
3. APT is D Wongs fert and I cant see him not putting enough K in, the Hygrophila Pinnatifida would be much redder in the tank to indicate higher uptake of NO3 and K

Low potassium (K) is holes in leaves, so adding 0.75 grams of Potassium Sulphate to tank after WC will increase the tanks weekly K ppm levels to EI levels ( call it a gram approx. and toss it in), it will do no harm.
 
Thank you Zeus. So just to recap:
  • I continue with Clive's EI regime as stated on the UKAPS EI article,
  • Add 1g KSO4 at WC
  • To remineralise could I also add Mg and Ca as follows: target 8ppm of Mg and 23ppm of Ca and dose that as well after WC?
If I could do the above then there is no need to buy any ferts, which is better for me in the long run.
 
I'd be willing to bet that this is damage from the shrimp eating your plants. Amano shrimp are known to do this. I mean the photo of the damage to your Tripartita to me looks incredibly obvious that it's been eaten. Half a leaf is removed entirely...
 
I usually don't mix my own remineralising "stuff" and just dose Dennerle Shrimp King KH/GH. I am happy to take advice as to what I should target if I were to change 30l every week. I would like for my water to more acidic as I suspect its just above 7. I have one of those cheap Seachem in-tank pH indicators just to get very rough idea.
 
Dennerle Shrimp King KH/GH.
So to date we are unaware of the Ca or Mg levels in this product, but a 3:1 ration for Ca:Mg shouldn't be far off
I assume you dosing it as it recommends
1618428241389.png


Which if cloning Dennerle Shrimp King KH/GH would yield 30 ppm Ca and 10ppm Mg in remineralization, so if your doing a 50% WC then your adding 15ppm Ca and 5ppm Mg

So with the APT and the Dennerle Shrimp King KH/GH your adding about 6ppm Mg
 
Thank you for the info. Although I still have some APT remaining I am going to stick to Clive's regime for a while and will keep using Dennerle Shrimp king. The only mystery is when I change 50% of the water, and remin as instructed the kH is sitting at about 3. The Gh then easily goes up to 8. I only have dragon rock so not sure where the rest of the stuff is coming from.
 
I am also still suspicious of my Amano's. There are a few big ones roaming around and I almost always see them sitting on those tripartita :) I have started giving some little bits of algae pellets, as there is clearly not enough algae around to sustain them. Quite interesting to see them scrambling for those pellets.
 
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