Targeting Potassium

[palcente]

I've attached 2 pics below named 'before' and 'after'. The before pic was taken quite a long time ago tbh, it was even before a rescape I did... but it's growth has mostly been the same until the potassium change. You can see some of the lower leaves aren't exactly healthy, ignore that, I was having fluctuating co2 at the time. You can see all the new leaves on it look very luscious, healthy and big. In the 'after' pic, you can see that the leaves don't quite look fully deployed, there is some warping on most of the leaves.

I've changed my K levels quite a lot, the plant grew as the 'before' pic anywhere between 20-60ppm of K. The 'after' pic is now that I have lowered the K to 5ppm.

I also have hygrophilia siamensis 53b, hygrophilia polysperma rosanervig, monte carlo, ludwigia glandulosa, limnophila hippuridoides, rotala h'ra, bucephelandra kedagang, anubias (mini, petite and coin), java ferns (regular and trident), pogostemon erectus, s.repens, and various cryptcorynes, echinodorus' and a sword plant. All of these have either not reacted or showed improve growth.

From my understanding, this is a gross overdose. Plants take up more nitrogen than potassium, and if you were to dose 30ppm of NO3 (standard EI), then this provides 6.78N, so potassium shouldn't need to exceed this number (6.78). Someone more knowledgeable correct me if I'm wrong on this please... but I guess this is where it gets more complicated if certain ratios are important... i.e the plants don't take up anywhere near as much magnesium as potassium, yet it seems it may benefit certain plants to have the potassium be lower... this is beyond my pay grade I can't imagine any tank that needs anywhere near 100ppm of K though.

I am at around 10ppm potassium now and my h.compact plant just started showing same symptoms as your. Not the pinholes, but the leaf surface is wrinkly and not flat/smooth. That's very interesting, I wonder if this is just a temporary event, like I observed with h.polysperma. My H.Siamensis' leaf shape is back to what it should be and is no longer curled, also ludwigia arcuata started growing larger. I started dosing Urea daily, I don't get any ammonia reading, but my NO2 went up, so I slowed down for now. I added some biomedia to my filter and will see if I can push it slowly to what I want, in the meantime I continue to front load CaNO3.

Will upload some pictures tomorrow.

 

[xZaiox]

my h.compact plant just started showing same symptoms as your. Not the pinholes, but the leave surface is wrinkly and not flat/smooth.

My H.Siamensis' leave shape is back to what it should be and is no longer curled

Ha, how interesting, looks like you've had the exact same response as me. I strongly suspect that these responses will vary amongst different plant species, but from our experiences, it seems that h.siamensis may be an example of a plant that doesn't cope well with high potassium? It would be interesting to hear if anyone has successfully grown it in optimal form in a high potassium environment.

My H.compacta is starting to throw out some flat-ish leaves now, so I'm hoping it may be able to adapt to the lower potassium levels. It's still pretty crinkly overall though.

 

[palcente]

My H.compacta is starting to throw out some flat-ish leaves now, so I'm hoping it may be able to adapt to the lower potassium levels. It's still pretty crinkly overall though.

For how long did you keep it at high K levels ? And how long did it take you to drop it to 5ppm?

 

[xZaiox]

For how long did you keep it at high K levels ? And how long did it take you to drop it to 5ppm?

I've had this plant for well over 1 year now, trying all sorts of high K levels. I've been at 5ppm for probably about 1 month now.

 

[_Maq_]

Interestingly, my Hygrophila corymbosa siamensis 'Brown' suffers from leaves deformations in my current experiment in all tanks in spite of very different treatment with K-Mg-Ca. Frankly, I'm perplexed.

 

[xZaiox]

Interestingly, my Hygrophila corymbosa siamensis 'Brown' suffers from leaves deformations in my current experiment in all tanks in spite of very different treatment with K-Mg-Ca. Frankly, I'm perplexed.

You included 'brown' in the name, is this a specific variant of the plant? I can't seem to find any information of such a thing online. I don't know if it'll help, but it's growing great in my tank now with the following parameters:

Spoiler: Fert dosing (tap to open)

Maintaining: Mg: 11 ppm, Ca: 33 ppm, dKH: 3, pH: 6.5 with CO2 on. Drop checkers are yellowish-green.
Lighting: Twinstar 900s on 100% intensity

Weekly dosing (these are done over 6x days):
Urea: 0.5N
NO3: 7.5 ppm
K: 5 ppm
PO4: 0.3ppm (rest comes from fish food, high stocking of fish)
Fe: 0.5 ppm (0.15 EDDHSA, 0.3 DTPA, 0.05 Fe Gluconate)
Mn: 0.25ppm
B: 0.03 ppm
Zn: 0.04 ppm
Cu: 0.005 ppm
Mo: 0.01 ppm
Ni: 0.00015 ppm
I have a lot of fat fish so I'd assume the plants are also being drip-fed NH4 from their waste. I know the micros are high, I plan to reduce them soon.

I've made many changes to most of the parameters of the lifetime of the tank due to difficulties with various plants, what I'm currently doing now appears to be working much better, however, the reduced potassium is really the only thing that worked for my siamensis 53b, perhaps it's a ratio thing with the rest of what I'm dosing? 😵

 

[_Maq_]

You included 'brown' in the name, is this a specific variant of the plant?

I've got it from this vendor . I've got no additional info. In my tanks, its colouration is far from that on the pic; upper leaves get a reddish hue, that's all. I should add that my DIY lighting is obviously inferior compared to top products. And, of course, I don't inject CO2.
Most of my plants which should be bright red in hi-tech are less strikingly coloured. I happen to like it that way. Even in exterior gardening or in cases of home (terrestrial) plants I regularly prefer natural varieties to over-coloured cultivars.

 

[palcente]

promised photos:

Hygrophila Siamensis (i believe that may be the brown variety @_Maq_ mjentioned, the colour is between olive green and brown)...

before at 100+ ppm K:


now at around 10+ ppm K:


For reference Siamensis 53b from Tropica grows like this (it was planted at 50+ ppm of K):


My h.compact is now showing similar leaf wrinkling as @xZaiox saw when he dropped K. Will report back if this is just temporary.


L.arcuata is growing better:

before:


now:


full tank shot for reference:


Matt

 

[palcente]

Hi,

It's been 2 months since I changed the potassium regime in my tank.

I switched from dosing NO3 with KNO3 to CaNO3 and Urea ceteris paribus.

Went from stupid amounts of K to ~4ppm that I front load mainly with K2SO4 or K2CO3, and a little bit from K2PO4.

I managed to get some of my Ludwigia Arcuata to grow as it supposed to, but not yet all of it. Partial success - I thought it's worth sharing...

Thanks,
Matt

PS. You can find sad ludwigia pictures for comparison in my previous posts.





Full tank shot - hazy water - I've been feeding baby brine shrimp every day this week, so that's the reason...

 

[hypnogogia]

I switched from dosing NO3 with KNO3 to CaNO3 and Urea ceteris paribus.

Is that calcium nitrate tetrahydrate?

 

[dw1305]

Hi all,

Is that calcium nitrate tetrahydrate?

It will be the tetrahydrate - Ca(NO3)2.4H2O. It is hygroscopic and really difficult to keep anhydrous.

Because you have two nitrate (NO3) molecules (~ NO3- ions) it is a good nitrate source and ~50% NO3.

cheers Darrel

 

[palcente]

Hi all,

It will be the tetrahydrate - Ca(NO3)2.4H2O. It is hygroscopic and really difficult to keep anhydrous.

Because you have two nitrate (NO3) molecules (~ NO3- ions) it is a good nitrate source and ~50% NO3.

cheers Darrel

Is that calcium nitrate tetrahydrate?

As per spec document.

Matt

 

[dw1305]

Hi all,

As per spec document.

Strangely it doesn't actually really matter what it was sold as, it will always be the tetrahydrate in use, unless it has been stored in a certain way. Unless it has been heated (to drive off the <"water of crystallization">) and <"stored in a desiccator"> (or freezer) and then placed in an air tight containers, it will be the tetrahydrate (Ca(NO3)2.4H2O).

As soon as you expose the anhydrous salt (Ca(NO3)2) to the air it will pick up atmospheric moisture until it is the stable tetrahydrate form. <"Calicum nitrate - Saltwiki">

...... Under standard conditions the tetrahydrate of calcium nitrate (Nitrocalcite) is the stable phase. With its relatively high solubility in water it is a highly soluble salt. The temperature dependence of the solubility is shown in the solubility diagram, where in parts the solubility increases extremely with increasing temperature. The dehydrations to the Trihydrate, Dihydrate and at least to the anhydrous calcium nitrate take place at 43 °C, 49.5 °C and 51 °C, respectively....

You can check by taking ~10g and leaving it out for a couple of hours in a sunny place, if it weighs more when you reweigh it? It has picked up atmospheric moisture. If it doesn't? It hasn't and was already in the stable form.

cheers Darrel

 

[hypnogogia]

Thank you both, @palcente, @dw1305. I’m going to start using this as well as urea in my future macro mixes.

 

[palcente]

Thank you both, @palcente, @dw1305. I’m going to start using this as well as urea in my future macro mixes.

If you change over from non ammonia based N sources, in my case I gradually phased them out. I did not detect any ammonia, but I noticed high NO2 in my tank. I suspect (total guess) in my NO3 centric conditions I had very little bacteria to process NO2, I added a little bit of biomedia and after few weeks that eventually fixed the issue.

 

[hypnogogia]

If you change over from non ammonia based N sources, in my case I gradually phased them out. I did not detect any ammonia, but I noticed high NO2 in my tank. I suspect (total guess) in my NO3 centric conditions I had very little bacteria to process NO2, I added a little bit of biomedia and after few weeks that eventually fixed the issue.

Thank you. I have quite a bit of bio media in my filter, but I now kow to monitor NO2 at the start. My plan is to start dosing urea alongside KNO3, worked out by the calculator, before reducing KNO3.

 

[dw1305]

Hi all,

I’m going to start using this as well as urea in my future macro mixes.

I think if you use RO water it definitely makes sense, you are going to need a calcium (Ca) source and this kills two birds with one stone. I use an occasional <"dash of tap water"> (~17 dGH & dKH) with my rain water, but <"that is adding 1 : 1 dGH : dKH">.

A strange question, but one that a lot of people have asked me, is whether they still need to add a remineralising salt (often <"Seachem - Equilibrium">) to their RO when they are adding magnesium (Mg) and calcium (Ca) with their fertiliser addition.

The question usually comes about because they've been told that they still need to buy the remineraliser, because fertiliser and remineraliser are "different products" .

cheers Darrel

 

[hypnogogia]

"different products"

But the same ions! It’s a good question though, and one that I’m pondering as I currently use calcium Sulfate to remineralise. If I’m targeting a specific dGH and dKH then I’m assuming is still need to remineralise.

 

[Oldguy]

I continue to front load CaNO3.

I think that calcium nitrate is a double salt of formula: 5Ca(NO3)2.NH4NO3.10H2O. It is typically made by reacting limestone with weak nitric acid and then 'neutralizing' with ammonia. Always a little careful about the ammonium ions and I dose over two days. I buy mine as prill for hydroponic use.
Have you considered also using magnesium nitrate. Mg(NO3)2.6H20. I got mine, also as prill, from a horticultural supplier to the top fruit trade.
It is possible to get high nitrate values this way.
Hate not having subscripts for chemical formulae.
You tank looks really good.

 

[dw1305]

Hi all,

But the same ions!

I think some people have gone back and explained that to the vendor, but I don't know if that has led to any change in "sales patter", my suspicion would be "probably not".

as I currently use calcium Sulfate to remineralise.

Calcium sulphate (CaSO4.2H2O) is a good calcium (Ca) source, <"but of limited solubility">. You can actually potentially use this to your advantage if you make up a "saturated calcium sulphate solution", you don't need to measure out the amount of salt, just ensure that there is some undissolved in the container when you add more RO water to it. You can't really mix it <"with other salts anyway">.

If I’m targeting a specific dGH and dKH then I’m assuming is still need to remineralise.

Yes, but should be able to achieve any combination of dGH and dKH. Because I use hard tap water it is always 1 : 1, but potentially you could make a <"designer mix"> if I was going to do this I might use @Roland 's <"recipe">.

cheers Darrel