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Micro fertiliser without K

Joined
13 Nov 2023
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37
Location
Berkshire
Hello
Can anyone recommend a liquid fertiliser that has micro and trace elements, but no potassium? Something like the Fzone Sola Micro (that one's not available in the UK unfortunately).
I have a no CO2 tank with a lot of plants, including big emersed ones in the sump. I'm having to dose quite a lot of N, P and Fe just to register on a test, but the potassium is off the charts, probably >50ppm. Seachem Trace is an option, but it's not cheap and doesn't have Fe/Mg.
 
I use CSM+B (Fe – 7,80%, Mn- 2,00%, B – 1,40%, Zn- 0,40%, Cu – 0,10%, Mo – 0,06%, E 202 & E 300 EDTA Chelated) for micros. Most Micros I've seen don't have any NPK.
Hm, that might work. How long do these last once dissolved in water? I use a dosing pump and don't want to bother with it for at least a few months after a refill.
 
I think whatever micros blend you choose, its impact on potassium content would be negligible given that your problem is > 50 mg/L.
You'd better switch from using solely KNO3 for nitrogen dosing. People are usually scared to use ammonium salts - and don't realize that commercial fertilizers often contain them, or at least urea, which is basically the same.
 
Hi all,
Can anyone recommend a liquid fertiliser that has micro and trace elements, but no potassium?
Seachem Trace is an option, but it's not cheap and doesn't have Fe/Mg.
It isn't a liquid, but the <"Solufeed Coir TEC"> should do and it is a lot cheaper.
I use CSM+B (Fe – 7,80%, Mn- 2,00%, B – 1,40%, Zn- 0,40%, Cu – 0,10%, Mo – 0,06%, E 202 & E 300 EDTA Chelated) for micro
That would also do.
I think whatever micros blend you choose, its impact on potassium content would be negligible given that your problem is > 50 mg/L.
Agreed.
I'm having to dose quite a lot of N, P and Fe just to register on a test, but the potassium is off the charts, probably >50ppm.
I'm going to tell you the problem is likely to be with your test kits. It is quite <"difficult to test for potassium (K) via colorimetry">, purely because nearly all <"potassium compounds are soluble">. It is easy to test for potassium via ICP, flame photometry, <"New bit of kit - MP-AES"> etc.

Despite having access to analytical equipment I don't use it very often for the tank water, I'm honestly of the believe <"that inferential methods"> are a lot less problematic and equally scientific.

cheers Darrel
 
Hi all,
I have a no CO2 tank with a lot of plants, including big emersed ones in the sump.
I'd definitely go to using a hydroponic fertiliser, it is going to be a lot cheaper in the long run. Have a look at <"Solufeed 2:1:4 and Solufeed Sodium Free TEC or Solufeed Coir TEC Combination">
People are usually scared to use ammonium salts - and don't realize that commercial fertilizers often contain them,
They do.
or at least urea, which is basically the same
I'm not sure you can say that. Personally I'd be <"a lot warier"> with ammonium containing salts (like NH4NO3) then I would be with those containing <"urea (CO(NH2)2)">.
I use a dosing pump and don't want to bother with it for at least a few months after a refill.
@Zeus. has been dosing urea <"using this method">. Solufeed have a range of fertilisers with differing N : P : K ratios <"Water Soluble (WS) Powder">.

cheers Darrel
 
Thanks everyone!
I add nitrogen and phosphate from aquadip and iron from seachem. The aquadip nitrogen does indeed contain potassium, so replacing that would be a good start, especially if these salts also work okay with an auto doser.
Unfortunately the tapwater here is also very high in K, even with half RO. I'm using the JBL test for it and it seems to match up reasonably well with what the water supplier says.

The information on the dangers of high K has also been a bit contradictory. The plants seem mostly fine, a couple show issues with potential calcium deficiency, but it's very hard to tell. Are there any dangers to the fish?
 
Perhaps you'd better consider an upgrade - complete mineralization of RO+DI water with individual salts. It's no big science.
I was thinking about it - but the end goal of this tank is to mostly stop with water changes, only top up with RO water, add the ferts/food that get consumed and nothing more. Buying all the salts and ph buffers seems like a bit of a waste in that case. Mostly there now, just need to figure out potassium and SiO2, and dial in the dosing pump.
 
the end goal of this tank is to mostly stop with water changes, only top up with RO water, add the ferts/food that get consumed and nothing more
It's hardly a viable option, I'm afraid. Whatever autopilot you set up, within time you'll learn you're flying in wrong direction.
 
Hi all,
I add nitrogen and phosphate from aquadip and iron from seachem. The aquadip nitrogen does indeed contain potassium, so replacing that would be a good start, especially if these salts also work okay with an auto doser.
I'd just use a hydroponic fertiliser, they are much <"more economical">. Have a look at the Solufeed range <"Solufeed 2:1:4 and Solufeed Sodium Free TEC or Solufeed Coir TEC Combination">.

You may also struggle with iron (Fe) availability using <"Seachem Iron">, it is <"ferrous (FeII) gluconate"> (C12H22FeO14) based. Seachem will <"spin you a line"> about this being "more plant available" but in <"hard, alkaline water"> the opposite is true.
Unfortunately the tapwater here is also very high in K, even with half RO. I'm using the JBL test for it and it seems to match up reasonably well with what the water supplier says.
What does your water company (Thames Water?) report say for potassium (K)? It is really <"easy to test for analytically">, but there isn't a maximum permitted value, so usually water companies don't report it. You find the same for magnesium (Mg) and phosphate (PO4---), no limits, so no reported value.
. Buying all the salts and ph buffers seems like a bit of a waste in that case.
I can tell you, unequivocally, that <"pH buffers are always a waste of money">. The companies that sell them know they are pointless, but they keep on selling them and it <"really, really p*sses me off">.
Mostly there now, just need to figure out ........ SiO2
You probably know what <"I'm going to say here">, unfortunately it is back to <"unscrupulous vendors">.

cheers Darel
 
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Thanks! Will have a look into the Hydroponic stuff. The water supplier is South East Water. I had a pdf that included K and made some comparisons to the large JBL test kit, but I can't find it anymore unfortunately. Useful info about SiO2, I'll stop measuring it.
 
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