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Can I mix
- Thread starter xandro007
- Start date
No, which is why EI dosing is done micro & macro on alternate days.
The phosphate reacts with the micro, namely chelated iron and precipitates out as insoluble and plant unavailable iron phosphate.
You must dose on alternate days. Also watch out urea is very toxic to fish.
The phosphate reacts with the micro, namely chelated iron and precipitates out as insoluble and plant unavailable iron phosphate.
You must dose on alternate days. Also watch out urea is very toxic to fish.
You won't see the precipitation as it is a micro fine powder of iron phosphate that stays in suspension, so possibly a slight cloudiness. Can only be revealed by testing for iron, using a proper lab grade test kit, and you will find no plant soluble iron present.
Also some micro's contain acid (ascorbic acid) to stop the micro solution going mouldy and/or unchelating, thus when mixed with phosphate it wont react. However your potassium carbonate will neutralise the acid allowing the iron (and other chelates) to react.
Hi all,
Why do you want to use K2CO3?
cheers Darrel
That is right, if you keep the solution acidic then you won't get the precipitation of insoluble hydroxides and phosphates.
Why do you want to use K2CO3?
cheers Darrel
I Will keep the solution acid
I want to use k2c03 because Ada use it
So I think it is the best way to ad potassium because Ada did many test
xim
Member
- Joined
- 19 Mar 2010
- Messages
- 499
I don't think it's the best way to add K. I think ADA use it just because it has good solubility.
All ADA ferts dosages are standardised to 1 ml per 20 litres of water. And with that dosage,
you will get 3.4 PPM of K from Brighty K. They can't do that with K2SO4 without changing the
dosage and breaking the standard they set because it's not very soluble.
By the way, I've found that the K from KNO3 I dose is enough for my tank. I think Tom Barr is right.
You don't need to dose as much K as NO3 in PPM number. Because NO3 is N accompanied
with O3 while K is only K which makes it disadvantageous in PPM number.
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Might want to consider adding potassium sorbate to act as a mould inhibiter as micro can be prone to go mouldy.
Hi all,
The same with HCO3- ion, the constituent elements can, and will, have been combined in millions of other molecules.
Each potassium (K+) ion is exactly the same as every other K+ ion.
cheers Darrel
It honestly doesn't make any difference where the K+ ion comes from. The potassium (K39) on Earth has been here for the last 4.5 billion years, it is highly reactive and it doesn't "remember" which compounds it has been combined in.
The same with HCO3- ion, the constituent elements can, and will, have been combined in millions of other molecules.
Each potassium (K+) ion is exactly the same as every other K+ ion.
cheers Darrel
xim
Member
- Joined
- 19 Mar 2010
- Messages
- 499
E202 is potassium sorbate. But it needs an acidic environment to work well enough.
Straight Shooter
Member
Precipitation: You will rarely ever get total precipitation of Fe and PO4 dosing at the same time. We spout this info over and over but no hobbyist that I know of has tested this theory properly. It's only academic, not particularly a fact that the new compound forms completely rendering dosing useless if macros and micros are dosed together. This is even less of a problem with mixes of EDTA DTPA etc where there are a number of chelates,
Straight Shooter
Member
I also find the "dose macros in the morning and micros in the evening" a bit silly too. The PO4 will reduce a little during the day due to plant uptake, but it is not any 'less-effective' at precipitating Fe from solution in the morning or at night.
So levels of PO4 do fall during the day, but PO4 is very good at staying put in the water column. It's an anion, and little is lost to the negatively charged substrates etc, hence why phosphate is such a PITA in water treatment. It's difficult to get rid of it in comparison to other ions. Nitrate is similar although the famous 'denitrification' by anaerobic bacteria is our friend here if necessary.
Potassium (K+) is much different as a cation as an example, it's encouraged OUT of the water column. PO4 will stay in the water column of your tank for weeks (or months, or a year....), so long as plants don't use it or you remove it with a water change etc.
Add iron at any point and you'll get FePO4 forming immediately. Strength of chelates (and a mix of them) makes a huge difference in this regard. The Fe is held up 'in-prison' and the PO4 can't get to it. Overtime the chelates break down and the PO4 will readily start reacting with iron. PO4 may have been added 12 days ago, but it will still begin this process of reaction with Fe immediately.
If I had an auto-doser I'd dose Fe just before lights-on where the light assists in making it available to plants. This ensures that maximum Fe is available for photosynthesis. As I rely on doing it by hand, and I've done it for many years, I can't be bothered dosing daily, just every 2 days and macros + micros at once. PO4 will likely still be in there from your last dose (if non-limiting nutrients are your thing), you're just topping up, don't worry about when you dose it.
I followed the advice to avoid dosing Fe and PO4 together for a LONG time... then I got lazy and dosed them together and guess what... there was no problem. Nothing changed, plants looked exactly the same, strong red plants, no cloudy precipitation etc. It's been a few years now and I'm still lazy and everything still works just fine.
So levels of PO4 do fall during the day, but PO4 is very good at staying put in the water column. It's an anion, and little is lost to the negatively charged substrates etc, hence why phosphate is such a PITA in water treatment. It's difficult to get rid of it in comparison to other ions. Nitrate is similar although the famous 'denitrification' by anaerobic bacteria is our friend here if necessary.
Potassium (K+) is much different as a cation as an example, it's encouraged OUT of the water column. PO4 will stay in the water column of your tank for weeks (or months, or a year....), so long as plants don't use it or you remove it with a water change etc.
Add iron at any point and you'll get FePO4 forming immediately. Strength of chelates (and a mix of them) makes a huge difference in this regard. The Fe is held up 'in-prison' and the PO4 can't get to it. Overtime the chelates break down and the PO4 will readily start reacting with iron. PO4 may have been added 12 days ago, but it will still begin this process of reaction with Fe immediately.
If I had an auto-doser I'd dose Fe just before lights-on where the light assists in making it available to plants. This ensures that maximum Fe is available for photosynthesis. As I rely on doing it by hand, and I've done it for many years, I can't be bothered dosing daily, just every 2 days and macros + micros at once. PO4 will likely still be in there from your last dose (if non-limiting nutrients are your thing), you're just topping up, don't worry about when you dose it.
I followed the advice to avoid dosing Fe and PO4 together for a LONG time... then I got lazy and dosed them together and guess what... there was no problem. Nothing changed, plants looked exactly the same, strong red plants, no cloudy precipitation etc. It's been a few years now and I'm still lazy and everything still works just fine.
Hi all,
Natural environment bit
Phosphorus is actually fairly reactive, it depends on the pH of the water, if you have alkaline water then the orthophosphate (PO4---) will combine with calcium to form insoluble calcium phosphate complexes. This will only become plant available under reducing conditions (in the substrate). The various phosphate ions have a high anion exchange capacity, and most phosphate is actually getting into water bodies bound to clay minerals via surface erosion of Maize fields etc. Optical brighteners in washing powders are less of a problem now, due to changes in legislation.
The problem for natural environments is that the world is awash with unnatural levels of phosphorus, which is building up into a huge reserve that (only sparingly) becomes soluble. In the UK it is estimated that it would take 1000 years to deplete this phosphorus reserve to back-ground levels, if we stopped adding phosphorus to the environment today.
The phosphorus surplus for the UK is estimated at 5 kg P ha-1 (from <https://www.gov.uk/government/uploa...achment_data/file/291507/scho0512buwf-e-e.pdf>).
cheers Darrel
It definitely is difficult to remove, although the problem is with the total amount, the water soluble fraction is a tiny percentage of the total reservoir. Usually you precipitate the orthophosphate (PO4---) out with iron oxide hydroxide etc. The aquarium version would be <"Ultiphos P"> or similar.
That is the one, we have to chelate iron, as soon as the chelator is photo-degraded the Fe+++ ion will form insoluble phosphate, hydroxides etc. Plants don't need a huge amount of phosphorus (P) (about 1/10 as much as nitrogen (N) & potassium (K)), and even less iron (Fe), so limited availability (as long as some is available) isn't a problem.
Natural environment bit
Phosphorus is actually fairly reactive, it depends on the pH of the water, if you have alkaline water then the orthophosphate (PO4---) will combine with calcium to form insoluble calcium phosphate complexes. This will only become plant available under reducing conditions (in the substrate). The various phosphate ions have a high anion exchange capacity, and most phosphate is actually getting into water bodies bound to clay minerals via surface erosion of Maize fields etc. Optical brighteners in washing powders are less of a problem now, due to changes in legislation.
The problem for natural environments is that the world is awash with unnatural levels of phosphorus, which is building up into a huge reserve that (only sparingly) becomes soluble. In the UK it is estimated that it would take 1000 years to deplete this phosphorus reserve to back-ground levels, if we stopped adding phosphorus to the environment today.
The phosphorus surplus for the UK is estimated at 5 kg P ha-1 (from <https://www.gov.uk/government/uploa...achment_data/file/291507/scho0512buwf-e-e.pdf>).
cheers Darrel
