# 4KH solution. Has anyone tried to DIY



## Piece-of-fish (21 Jul 2009)

Hi, found some information on the Tom's page which says you can do your own 4kh solution (or any kh) using baking soda and distilled water plus the kh test kit. 
Has anyone tried this method. I know the test could be inaccurate but still it would be cost effective in my opinion.
Regards.


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## chump54 (21 Jul 2009)

I've been using my own diy 4dkh solution. using this. while I'm not sure mine is 100% accurate I do know that once It goes very yellow my fish start to struggle so it must be close enough. try it out, if you have RO water why not?

chris


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## JamesC (21 Jul 2009)

This is how I make mine:

Accurately weigh 6.0g of Sodium Bicarbonate and add to 5 litres of deionised water to make a 40dKH solution.
Mix 100ml of the 40dKH solution with 900ml of deionised water to give you 1 litre of 4dKH reference solution.

James


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## Piece-of-fish (21 Jul 2009)

Thank you people for replies and links. The problem is i dont have so much water nor i have scales so i am kinda thinking to try to mix it with a small amount and using a kh test to make any adjustments later.
What you think?


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## aaronnorth (21 Jul 2009)

Piece-of-fish said:
			
		

> Thank you people for replies and links. The problem is i dont have so much water nor i have scales so i am kinda thinking to try to mix it with a small amount and using a kh test to make any adjustments later.
> What you think?




it needs to be accurate. i am guessing here but a difference in say, 0.5g either way of James recipe i doubt would show a difference on the test kit, however it may be off 4degrees by quite a bit.

EDIT: forgot to say you can always scale it down, but it just makes it a bit harder to get the reference accurate.


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## GreenNeedle (21 Jul 2009)

Do you have some API test tubes or similar?  If so I shall weigh how much bicarb goes to the top of the 5ml line for you 

DI water is available in Tesco, Wilko, Boyes, Halfords.  etc

AC


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## Piece-of-fish (21 Jul 2009)

have got that API test bottle and would be greatful if you could do that for me. By the way is it 6g which makes 40dkh water cause i find some other figures as well, 4,9 lets say. 
Regards.


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## aaronnorth (21 Jul 2009)

Piece-of-fish said:
			
		

> have got that API test bottle and would be greatful if you could do that for me. By the way is it 6g which makes 40dkh water cause i find some other figures as well, 4,9 lets say.
> Regards.




it depnds how much water you use 

3g to 2.5l is the same as 6g to 5litres.

There are lots of different recipes out there but they all produce exactly the same product


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## Piece-of-fish (21 Jul 2009)

I mean i found some different figures for 5l of water to make 40dkh


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## chump54 (21 Jul 2009)

I think the difference arises because (i'm guessing) James doesn't dry his bicarb out, possibly?

Chris


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## JamesC (21 Jul 2009)

Initially somebody calculated the amount incorrectly and it was a while until is was noticed. This is why you sometimes see the wrong amount in some old posts. The 6g that I use is the correct amount.

You can use less water but the problem is that the accuracy is then reduced. If you have to but scales etc then it's probably cheaper to buy the bottled stuff. It lasts yonks anyway. Also you can't make it up using KH test kits as they just aren't accurate enough.

It's not a question of heating sodium bicarb as it decomposes to sodium carbonate and CO2. When I did it I used a fresh bottle of NaHCO3 so it would be dry. Don't use an old bottle as it absorbs moisture from the air.

James


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## GreenNeedle (21 Jul 2009)

> It's not a question of heating sodium bicarb as it decomposes to sodium carbonate and CO2. When I did it I used a fresh bottle of NaHCO3 so it would be dry. Don't use an old bottle as it absorbs moisture from the air.



I think this was the initial cause of all the disagreements.  It started off at X amount and then people started talking about moisture and someone changed it to a lesser weight and baked the Bicarb without taking into account the reaction.

I think it was 5.999 something that was eventually agreed on as good enough to take into account the moisture level.

I shall weigh out 6g later and photo the test tube 

AC

AC


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## TLH (21 Jul 2009)

JamesC said:
			
		

> You can use less water but the problem is that the accuracy is then reduced. If you have to but scales etc then it's probably cheaper to buy the bottled stuff. It lasts yonks anyway. Also you can't make it up using KH test kits as they just aren't accurate enough.



You can increase the accuracy of your test kit by using a bigger sample. If you use 20ml instead of the normal 5ml then you need to add 4 drops to get 1dkh instead of 1 drop. This would mean you can measure in 0.25dkh steps. You can go even further with it if you want and use a 40ml sample for 1/8 degree steps even.

I do agree though you need to be fairly accurate straight off the bat otherwise you'd be sitting there testing all night and you could go through alot of test kit before getting it right.


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## Piece-of-fish (22 Jul 2009)

Ok, i see now. These are very informative replies. I am really greatful for you all beeing here for us newbies. It makes it so much faster and esier to get into planted with all your support and knowledge.
Must have a look whats the price of the water tomorrow and if its worth doing. Maybe like James mentioned its better to buy a ready bottle, cause i wont trust my own creation now anyway   until  at least compare it with a ready one from the shop first. 
Correct me if i am wrong (read about this somewhere as well), one of  advantages of doing your own solution could be that you can make any kh solution so you could make your drop checker change colors at different ppm of co2 if desired.  For example if you see that your fish can cope with 40ppm you do the solution so it would go green on 40 etc.

Edward.


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## GreenNeedle (22 Jul 2009)

> one of advantages of doing your own solution could be that you can make any kh solution so you could make your drop checker change colors at different ppm of co2 if desired.



If you have doubts over your own 4dKH then making the others you would also have doubts 

This is easy to do with homemade or bought.

For example take 250ml of 4dKH (Homemade or bought)  Add another 250ml of DI.  You now have 1 litre of 2dKH which 'should' show the 'usual' green at 15ppm.

Can't really accurately go upward with the bought but the simple equation suits all dKH for the homemade.

You know the 5 litres is 40dKH so you 'cut it' to whichever KH you want.  If you want 6dKH then you would mix 10ml 40dKH with 66.66ml of DI etc.

Pretty easy with a scale, some DI and a calculator.  Whether you think you need all that amount is another issue however I tend to save 500ml of the 40dKH and use the rest to make up my fert solutions   Which I also use the scales for 

Nothing wasted in this house.

AC


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