Making 4dkh Reference Solution

[montyII]

I stumbled across a recipe to make up your own 4dhk solution for a drop checker using bi-carb soda and distilled water. It suggests using a teaspoon to measure out 6 grams of bi-carb into 100ml, then diluting it further.

Will using the teaspoon give an exact enough 4dkh refernce solution to give an accurate CO2 level? Or is it essential to weight the bicarb? (Me no have scales).

Are there any other methods people use to make the reference solution?

Cheers,

Nick.

P.S: Sorry if this topic has already been done to death, I couldn't find it anywhere.

 

[Underwurlde]

There are many threads on this subject on the internet, but they stem from the barreport (I think).

The method for making a home made reference solution has 'progressed' shall we say, & unravelling those threads is a bit of a nightmare, so the correct answer to this may be interesting.

Formermally, to make a ref solution you took some bicarb, baked it for 1/2 hr in the oven (at various temperatures dep on which thread you were reading and the date), and then measured 4.99g of it and added this to 5 Litres of water to make your reference solution. Now, you had to bake it first to expell any water that would otherwise make the dry weight heavier and as a result the solution inaccurate, however it was then pointed out that taking baking power above 60 deg C would change it chemically and therefore you could not bake it, therefore could not dry it, therefore could not weigh it accurately.

I think that you now take 6g and add that to 5L of water... or measure it by volume. I got a bit lost in the threads and various people's opinions and who to trust etc. so it would be good if someone came in with a definative answer to this. (Personally, I can't see why putting some Bicarb in the airing cupboard would'nt work to dry it out and yet keep it's chemical compound stable).

Andy

 

[montyII]

Ta for reply, underwerlde.

(Personally, I can't see why putting some Bicarb in the airing cupboard would'nt work to dry it out and yet keep it's chemical compound stable)

Hmmm... I don't have an airing cupboard. In fact I don't think I even know what one is......?

All sounds a bit complex.

These are the two methods I've found:

From aquariumlife.com.au:

1. Dissolve 1 tsp (6 grams) of sodium bi-carb into 1 litre of distilled water.
2. Take 10mL of this solution and disolve it further into 490mL of distilled water.

and from plantgeek.net:

First we will need to create a saturated baking soda solution. Get a cup and put a tablespoon or two of baking soda in it. Then fill the cup with distilled water, stir and let it sit for about an hour. The solution will reach equilibrium and no mater how much solid there is in the bottom, the liquid will have 7.8g/100mL sodium bicarbonate at 20 degrees Celsius.

Next using a dropper, fill a 5mL vial with the solution making sure not to stir up the contents on the bottom. You should now have .39 grams of baking soda. Add this to 3,250 mL of distilled water and that will give you a 4dKH solution.

Note: Sodium Bicarbonate's solubility changes with temperature so you might need to add a little more water if your temperature is higher.

Will have a look at the barrrepot too and see if I can make sense.

For now I might just use the teaspoon method, must give you a rough idea, surely.

Any other advice appreciated.

 

[Underwurlde]

The first method I have heard about but did not ring true, because before that, people were saying things like: Take 4.9932g, measured using very accurate weighing scales and dissolve that into exactly 5Litres of water..... And then it was: Oh, take about 6grams into 1 Litre of water... And I thought, hold on, isn't the idea of this method is to be bang-on accurate with thing? People were actually going out & buying accurate digital weighing scales from ebay

I have not heard about that last method from the plantgeek. Sounds well cunning and the thing to do to get an accurate 4dKH solution... I would try that one, but like I said, I have not heard of it & I don't know what the feedback is on this method.

Andy

 

[montyII]

Yeah, I thought the teaspoon method might be a bit innacurate.

I'm starting to think that buying some could be the best option, but I might try the saturated solution method until I can find some. It has to be better than using tank water.

Cheers.

 

[xxBarneyxx]

I looked into a lot of different ways of making it. In the end I just bought a bottle from AE and had done with it

 

[Themuleous]

Yeh, to be honest for the sake of 8quid or whatever it is save yourself the hassle and buy some, the bottle from AE will last you ages.

 

[montyII]

Will see if I can find some. AE not an option, I'm in Australia, but I should be able to find some somewhere.

Cheers.

 

[Themuleous]

AE will ship to Australia