# Ei Dosing question



## Weslp00 (10 Apr 2017)

Hi everyone..
I have a question about Ei dosing particularly about making up dry Macro chemicals into solution.
I need to make up a litre at a time because I am dosing a 1000litre plant tank and its established going well after a year.
The problem I get is that there is a precipitation in the made up Macro mix that looks like a white deposit that drops out and forms in the bottom of the storage vessel. Is there a way of stopping this because I don't want it bunging up my dosing pump.. It dosent happen with the Micro (chelated ) chemicals.

Any ideas?

A


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## Ed.Junior (10 Apr 2017)

I would guess it is probably potassium. Make sure you did not reach the solubility limits. For instance, you cannot add a kilo of KNO3 to 1 liter and expect it to dissolve.

Either by using a bigger solution volume, or increasing the dosage volume, you can reduce the concentration and make sure everything gets dissolved.

Try rotalabutterfly.com caculator. It will tell you the solubility limits.


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## Weslp00 (10 Apr 2017)

I think I understand this...

Use the same amount of salts but double the RO water I am using to dissolve it in to solution and then proportionally double the dose of that solution into the tank ??


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## Zeus. (10 Apr 2017)

I make up about 4litres at a time for my 500l tank for auto dosser not had an issue but only had it fitted a few weeks.
what water did you use? Tap or boiled water to remove temporary hardness
I use RO water.

Edit - both posted at same time


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## Daveslaney (10 Apr 2017)

If solubility is your issue,Depending on your EI mix.You can always mix the mgs04 in with the micros.
Or swap out some of the no3 for urea to reduce the dry salts in the macros mix this way.


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## Weslp00 (10 Apr 2017)

Excellent. I am getting the impression that it could be a solubility problem. Could be that I have over saturated the dry salts with not enough water in the mix process. Yes I do use RO water to remove hardness but I microwave/warm it up to make it dissolve the crystals quicker. I am using Pot Nitrate, Pot Phosphate and Mag Sulphate.

I get the bit about removing mgs04 to stop a reaction but what is "urea" replacement for the no3 all about please???


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## Ed.Junior (10 Apr 2017)

Do not go beyond 50°C for the micros. EDTA is the most common chelate for micros, and is temperature sensitive: lasts months at 4°C but hours at 150°C

Sent from my SM-G920F using Tapatalk


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## Daveslaney (10 Apr 2017)

Just move the mag sulphate from your macro mix and add it into your micro mix with your chelated traces, This should solve your solution problem. I do my micro mix like this with no issues.
Urea is a stronger N (x3)source than no3 alone.So it would alow you to reduce the dry salts in your macro mix to aid solubility.
But as its a ammonia based source of N there is a limit to the amount you can use to replace some of the no3 in your mix. Only just started using it in my EI mix so still trying to get my head around some of the implications of using it. The results are looking good,It isnt without risksBut it is ok used in
low quantitys.


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## papa_c (10 Apr 2017)

re solubility level, i've cut this info from James Planted Tank, hopefully this helps...

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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## Weslp00 (10 Apr 2017)

Wow thanks guys ! Great forum great advice ! I will start the experiments


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## Weslp00 (13 Apr 2017)

Oh well so much for using more water to make up the same concentration of Macro mix. It just took longer for the white compound to drop out and fall to the bottom of the storage vessel! Blast ...
 What is this reaction ?
Is it harmful? Is it spoiling the nutritional value of the macro fert ?
As suggested it looks like its the Mag Sulphate and im liking the idea of mixing it with the micro chelated fert or will it spoil that too?
Any more ideas guys or shall I just ignore it and clean out the storage vessel more often??  :0)


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## papa_c (13 Apr 2017)

for comparison i mix the follow quantities with 1000ml water and don't have any issues

120g mgso4
35g kno3
15g kh2po4

micros are mixed in a separate container, also i dissolve these in warm water, enough mix to last 3 weeks

what quantities are you using?


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## Weslp00 (13 Apr 2017)

Yes I am using the same Macro chems but I measure in tablespoons.
Its a 1000 litre tank so use..
3 TABLESPOON KN03
1TABLESPOON KH2P04
5 TABLESPOON MGS04

Mixed with 1000ml of RO water

So not sure what the weights are  but that amount seems to work well and the plants are doing well.

But something in the mix is reacting and leaving a white residue in the dosing storage container.. and I am not sure what it is and how to stop it ??


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## dw1305 (13 Apr 2017)

Hi all,





Weslp00 said:


> Is it harmful? Is it spoiling the nutritional value of the macro fert ?


Yes it will, whatever the compound is that has formed it will mean that either less (or none) of that element is present as an ion and plant available.





Weslp00 said:


> As suggested it looks like its the Mag Sulphate


It could be, all nitrate compounds are highly soluble, so you can discount them, same applies to potassium compounds, they are highly soluble. Magnesium phosphate compounds are "sparingly soluble" in water, but more soluble in acids. 

That is probably the likeliest option.

I'd try adding some white vinegar and see if the precipitate goes back into solution.

cheers Darrel


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## Daveslaney (13 Apr 2017)

I have no problems mixing the mg in with the traces in the micro mix. Have done it for weeks.


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## ian_m (13 Apr 2017)

Where did you get your salts from ?

Normally you will not have any solubility issues at ei mixture levels.

Could be that you have been ripped off over the potassium nitrate and have been supplied the cheaper less soluble  calcium nitrate, which can also precipitate out as insoluble calcium phosphate. Also heard of internet supplied salts being bulked out with chalk.


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## Ed.Junior (14 Apr 2017)

ian_m said:


> Normally you will not have any solubility issues at ei mixture levels.



EI aims at tank concentration, not your solution. You are right when we consider that people are making "standard" solutions, as indicated by the seller (e.g. NiloCG, etc.)

I see many people getting issues when they have a big tank and plan to use a small daily dose (100g Tank and 5ml dose). As a starting point, I advise people to keep a 3000:1 ratio between tank size and dose (e.g. 300 liters tank and 100 mililiters dose).


This gets worse when people think of solubility as something isolated per salt, and mix K2SO4, KNO3 and KH2PO4 and then wonder why something is precipitating: it is a lot of K. If you warm your water before mixing, this could also happen as it cools down.

For people that would like to avoid the math/chemistry calculation, I really suggest using rotalabutterfly.com

Sent from my SM-G920F using Tapatalk


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## Weslp00 (14 Apr 2017)

Thanks for the information  guys. The other day I made up a macro mix in 1000ml RO water with no mag suphate and hey presto its still clear after 2 days....so it is deffo a  solubility issue with the mag sulph as pointed out by Darrel. So how much white vinegar shall I add to the mix bearing  in mind the large quantities of the 3 compounds quoted  above. I believe this will lower the ph and help the mag suph dissolve ?
By the way I am getting my ferts from APF so I doubt if here is anything fishy there..no pun intended !


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## Weslp00 (15 Apr 2017)

I've got another idea re the Mag Sulphate solubility problem. How about I dose it separately.

I have a 3 head Kamoer Doser so could put the Chelated Micros on pump head 1 as it is now and the KNO3/KH2PO4 mix on pump head 2 (I don't have problems with those mixing) Then put the Mag Sulphate on pump head 3.
Only thing is how much RO water do I dilute it with? When I mix all 3 compounds together I use 1 litre of RO water... would I do the same if I split them up and use 1 ltr for the KNo3/KH2PO4 mix and 1 litre for the lone Mag Sulphate?


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## Daveslaney (15 Apr 2017)

Yes you would use the same dilution ratio for each.
I take it you are wanting to follow APFUKs EI mix?
If so the amounts you are using are recomended to be mixed with 500ml of water in the dosing containers.
As you are using 1000ml of water to mix your solutions. You are in fact only doing 50% of thier recomended EI dose.Unless you are dosing 20ml per 50lrs of your solution?. Which asks the question why should you have solubility issues? As you are using double the amount of water.


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## Weslp00 (15 Apr 2017)

Thanks for the answer re the dilution ratio.. that should stop it reacting as it would in fact mix in the tank and end all the problems hopefully !

As for the APFUK EI mix recipe ..yes I am following it and yes I do use 1000ml of water per mix not 500ml. APFUK use teaspoons measures of fert per 500ml of water to make their mix. The reason I do it differently ( and use tablespoons) is the size of the tank that I am dosing... I am dosing at least 1000 litres of tank water as per the picture at the beginning of the thread.The tank is 7 feet long.
So I was getting through a lot of fert. solution.
That gave me the idea of just doubling up on everything per mix session to make more and converting from teaspoons to tablespoons at the same time.. less counting that way!

Looks like I better get another storage bin/ pump going for separate Mag Sulphate solution now..thanks for the info guys!!


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## Daveslaney (15 Apr 2017)

Ok i see. You can do it with the mg sererate or the mg in with the micros. Makes no odds really.
I mix mg in my micro mix as there is only one spoon of trace powder in it. With no solubility issues at all.


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## Weslp00 (15 Apr 2017)

Mg sererate?   is this different to mag sulphate.. Wish I was a chemist


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## Daveslaney (15 Apr 2017)

Lol its a typo always happens when on my phone.
I am old my eyes arnt what they used to be.


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## Weslp00 (15 Apr 2017)

Lol!    me to ..its not only my eyes... It all the rest thays going wrong !
 I thought that you had invented a new fert. I will let you know how it goes


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