# so I want to make a 1liter macro fertilizer solution...



## jarthel (22 Dec 2009)

and it should last me for half a year. Can I just add 2mL hydrochloric acid (as mentioned by theplantedtank) so it doesn't "spoil"? or maybe preservative is only required in a trace solution?

Thank you


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## CeeJay (22 Dec 2009)

Hi jarthel.

If my memory serves me correctly your enquiries have been for a 300 litre tank.
If you mix up one litre of solution for a 6 month supply, there will be so much powder in the solution that it would probably be like treacle  . 
You may need to increase the volume of water and increase the dosing ml per day to suit.
Alternatively, you could mix up a 4 week batch which seems to be the most popular, then you have no fear of it 'spoiling' as you are mixing up fresh stuff every 4 weeks. One less chemical in the house   .
If you are talking about an All in one recipe, then you would need some form of acid to stop the traces reacting with the macros.
I keep my macros and traces in seperate bottles and dose alternate days. Keeps it simple   .

Chris


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## dw1305 (22 Dec 2009)

Hi all,
Chris is right you can't make really saturated stock solutions as all the salts in solution are additive, and sooner or later the one with the lowest solubility will come out of solution (re-crystallize). Salts are also more soluble at higher temperature, so as the temperature of the stock solution cools, salts will come out of solution and may be difficult  re-dissolve even if you re-heat the solution. 

Some salts are very soluble (potassium nitrate - 360g/1000 mL at 25Â°C), but many phosphorus compounds for example are much less soluble, so you might add the very soluble KH2PO4 (monopotassium phosphate), but it could re-combine with the calcium (or magnesium) all ready in the solution and precipitate out as tricalcium orthophosphate Ca3(PO4)2 or similar.

As long as the salts are in solution and the bottle air tight concentrated stock solutions keep for long periods, and because they are concentrated you don't get the problem of algae growth (weak "Long Ashton" or Hoaglands solutions must be kept in the dark for this reason.) The HCl is to acidify the solution and keep nutrients in solution, rather than as a "preservative". 

A further problem is that Iron chelate FeEDTA is photodegraded by light so must also be kept in the dark, and the non-chelated iron forms insoluble ferric phosphate (FePO4) very easily. 

As suggested the best option would be to keep 2 separate solutions - 
A PMDD+PO4 formula for macronutrients.
A micronutrient traces solution (kept in the dark).

A final point is that the "Fluidsensor" Iron + traces mix James Suggests for his "all in one solution" <http://www.theplantedtank.co.uk/allinone.htm> is very reasonably priced at Â£5.50 for 100g <http://www.fluidsensoronline.com/ep.../Products/PN-100-TR/SubProducts/PN-100-TR-100>), and a 100g is going to last a long time.

cheers Darrel


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## chris1004 (22 Dec 2009)

Hi,

To add to the above two replys the standard 4 week solution is used by most as it allows for adjustments/tweeks of the ferts to suit, as you start using them and getting used to the feel of using them you are able over time to fine tune the exact mix that suits your tanks requirements with the minimum of waste. If you make up large batches you will lose this ability or have a great deal of waste. I agree that on the face of it large batches does seem to cut out even more work but in reality when you get used to making a fresh batch its no harder than making a cup of tea or coffee. A quantity of this, that and/or the other fill with water and shake......

I do make a point however of always writing down exactly the ingredients used in each mix so when it comes time to mix the next batch you can make informed decisions rather than relying on what may be a flakey memory (mine certainly is).

I also keep the macro and micro solution seperate and dose alternate days. If your trace mix is using an EDTA iron chelater then were you to dose both macros and micros on the same day then the iron chelator will react with the phosphate and make the water cloudy, albeit temporarily. The iron in the trace mix that I am currently using is based on a HEEDTA chelator (Peter Haak's) which doesn't react with the phosphate so if you were to go down the route of mixing an all in one solution then maybe thats food for thought. I think its good practice though just to dose on alternate days it certainly works fine that way.    

Regards, Chris.


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## CeeJay (22 Dec 2009)

Hi all

Darrel
I just love your replies. So informative. Keep 'em coming   .

chris1004


			
				chris1004 said:
			
		

> I do make a point however of always writing down exactly the ingredients used in each mix so when it comes time to mix the next batch you can make informed decisions rather than relying on what may be a flakey memory (mine certainly is).


That's exactly what I do   .
Because the old memory ain't what it used to be    I've even laminated a sheet of A4 paper with the baseline EI amounts for my tank (just to remind me   ). 
I now write my adjustments on it with a 'dry wipe' marker pen and shove it in the (dark) cupboard under the tank with my ferts and just dig it out when my ferts solution runs out every 4 weeks. 
Easy to clean too  .

Chris


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## aaronnorth (22 Dec 2009)

chris1004
chris01
I wish one of you would change your name, I get so confused    

here are some figures off of JamesC's site:

Potassium Nitrate  	36g per 100ml
Potassium Phosphate 	22g per 100ml
Potassium Sulphate 	11.1g per 100ml
Magnesium Sulphate heptahydrate 	25.5g per 100ml
Calcium Sulphate dihydrate 	0.24g per 100ml
Calcium Chloride anhydrous 	74g per 100ml


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## jarthel (23 Dec 2009)

in the end (like last night), I decided to use powder 

thanks everyone for the help


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## dw1305 (23 Dec 2009)

Hi all,
Chris1004 wrote:


> The iron in the trace mix that I am currently using is based on a HEEDTA chelator (Peter Haak's) which doesn't react with the phosphate so if you were to go down the route of mixing an all in one solution then maybe thats food for thought


thank you! very useful, and not something I was aware of. 
cheers Darrel


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## a1Matt (23 Dec 2009)

dw1305 said:
			
		

> Hi all,
> Chris1004 wrote:
> 
> 
> ...



JamesC has contributed some very useful posts to this forum detailing different chelators and what ph's they are best suited for. A search for 'chelator ph' will return some relevant results. His site ( : http://www.theplantedtank.co.uk/traces.htm  ) also has links to some suppliers of different traces including Peter Haak's.


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## CeeJay (24 Dec 2009)

Hi Aaron


			
				aaronnorth said:
			
		

> chris1004
> chris01
> I wish one of you would change your name, I get so confused



So I did.   
I agree, too many Chris's about, and I was kindly allowed to change it.
chrisr01 is now CeeJay  

CeeJay


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## aaronnorth (24 Dec 2009)

CeeJay said:
			
		

> Hi Aaron
> 
> 
> 
> ...



phew  
I could only recognise the difference because of you post layout  
Thanks, Aaron


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