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Where can i get a big bottle of drop checker solution??

GHNelson

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100ml CO2 drop checker test solution - monitor levels of CO2 in your Aquarium | eBay
Aqua Rebell - CO2 Check - 30 mg/l - 250 ml - Aquasabi
1607122979724.png
 
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Yeah that's weird, I haven't dosed co2 for some time but when I did dc solution in big bottles was in abundance but now all the usual suppliers seem to be only doing 10ml bottles.
 

Witcher

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1.2 g of bicarbonate soda (available probably anywhere in food shops etc.) dissolved in 1000ml of deionised water will give you 40 dKH solution. Then mix 100 ml of that water with 900ml of pure DI water - it will give you roughly 4dKH solution for the fraction of "official" price.

This may help as well:
4dKH Solution
 

Sammy Islam

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I got my drop checker solution from ebay, the one you have to mix. The instructions say put 2ml of 4dk water in to drop checker and add 3 or 4 drops of bromo blue. Am i looking for a dark blue? Does it matter if its 3 or 4 drops?

Can i not just add it to the whole bottle instead of measuring out a little bit at a time?
 

Sammy Islam

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Yes, from what I've read adding too much changes the dkh of the solution, affecting how it works.

I filled up drop checker just over half way and put in 4 drops which gave me a bright blue. Today at lights on it was green but nearly clear, so i'm guessing i have to put in a couple more drops to get it to the colour of the premade solutions (a lot darker)
 

Sammy Islam

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I was wondering why my drop checker wouldnt go limegreen/yellow like it use to with the old solution. Turns out the 4dkh solution i ordered from ebay is actually 5dkh after testing with kh test, makes sense why my drop checker is darker green. 🙈

Found some bicarbonate of soda hidden at the back of the cupboard so will try mix my own tomorrow. Easiest way seems to be 0.3g to 500ml DI Water. Seeing as i have accurate scales does that mean i can half that 0.15g to 250ml DI to make a smaller batch of 4dkh water?
 
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dw1305

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Hi all,
Turns out the 4dkh solution i ordered from ebay is actually 5dkh after testing with kh test
There is no way of knowing, but my guess is that this is the wrong way around, and that your test kit is reading 5 dKH in a 4 dKH solution.

I'd think of it this way. You give me a £1 coin, and rather than accepting it is £1, I weigh it, and say "it weighs as much as £2, so it is actually £2" and give you a pound back. What is more likely? That the coin is counterfeit? or that the scales are wrong?
Found some bicarbonate of soda hidden at the back of the cupboard so will try mix my own tomorrow. Easiest way seems to be 0.3g to 500ml DI Water. Seeing as i have accurate scales does that mean i can half that 0.15g to 250ml DI to make a smaller batch of 4dkh water?
You can, but even with accurate scales you are likely to get a more accurate result using <"serial dilution">. I also think it should be 0.03g NaHCO3, it is really easy to get lost in the powers of 10, but @Manuel Arias breaks down the maths in thread linked below.

Because NaHCO3 is really cheap to buy I would start with <"3g of NaHCO3 made up to 500 mL with DI water"> to give you a 400 dKH stock solution, and dilute from there.

cheers Darrel
 

Sammy Islam

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Hi all,

There is no way of knowing, but my guess is that this is the wrong way around, and that your test kit is reading 5 dKH in a 4 dKH solution.

I'd think of it this way. You give me a £1 coin, and rather than accepting it is £1, I weigh it, and say "it weighs as much as £2, so it is actually £2" and give you a pound back. What is more likely? That the coin is counterfeit? or that the scales are wrong?

You can, but even with accurate scales you are likely to get a more accurate result using <"serial dilution">. I also think it should be 0.03g NaHCO3, it is really easy to get lost in the powers of 10, but @Manuel Arias breaks down the maths in thread linked below.

Because NaHCO3 is really cheap to buy I would start with <"3g of NaHCO3 made up to 500 mL with DI water"> to give you a 400 dKH stock solution, and dilute from there.

cheers Darrel
Thanks Darrel, makes sense but doesn't explain why the drop checker is dark green rather than verging yellow, so that's why i would like to make my own solution to test.

I can make a bigger batch, but the problem i have is mesuring out the water precisely. How do i do that? I only have general containers with 1/4L, 1/2L and 1L marks.
 

dw1305

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Hi all,
but the problem i have is mesuring out the water precisely.
Just by weight. Because water has a density of one, a kilogram of water has a volume of one litre and one gram = one millilitre.

Even in the lab. I use the scientific balances, rather <"than volumetric flasks">, for most things. I only use a pipette now for very small volumes
so that's why i would like to make my own solution to test.
That should tell you. You will have made <"a standard"> that you can use for calibration.

cheers Darrel
 

Oldguy

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measuring out the water precisely.
If you have accurate scales/balance then you can weigh the water. Assume 1.00 gram per ml/cc. I have calibrated glass ware in the past working to three decimal places. B@ll breakingly tedious.

As @dw1305 says serial dilution is the best way as it reduces errors and simplifies measurements. Evan though I have 2 lire measuring cylinders I use 5litre plastic bottles and 500ml drink bottles for serial dilutions of factors of ten.

Measuring cylinders are cheap thanks to eBay should you feel the need.
 

Sammy Islam

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Hi all,

Just by weight. Because water has a density of one, a kilogram of water has a volume of one litre and one gram = one millilitre.

Even in the lab. I use the scientific balances, rather <"than volumetric flasks">, for most things. I only use a pipette now for very small volumes

That should tell you. You will have made <"a standard"> that you can use for calibration.

cheers Darrel
Thanks, I have successfully made 4dkh water, i tested it a few times to make sure. I also doubled the amount of test fluid to 10ml so every drop of indicator is for 0.5dkh.

Might test 20ml of it and increase the accuracy more, but i'm pretty happy with it.
Might test 10ml of the ebay fluid to find out if it is 4.5 or 5dkh aswell.
 

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