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

Hi all,
@dw1305 Would using RO water with a TDS at ~20 be ok for making the solution or it would need to be flat 0?
It depends a little bit which ions make up the twenty mg/L TDS (~60 microS), but it should be OK. It is still a <"small amount of ions">.
If you can get pure KCl it is 0.746g KCl in one litre to give a 1411 microS solution.
Do you know how hard the water in the RO feed was? If it was slightly salty, but soft, (for this use) it is effectively 0 ppm TDS, we are only interested in bicarbonate (HCO3) ions

Even if the TDS comprise entirely Ca++ and 2HCO3- ions it is still a small difference to the dKH (it will be <"4 and a bit" rather than "4")">.

It doesn't matter if the feed water to the RO unit had been through ion exchange (a unit that uses NaCl). It will still have <"the same carbonate content"> as the original supply.

cheers Darrel
 
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Do you know how hard the water in the RO feed was?
Raw from the faucet, the API KH test kit tells me 2.5dKH. Water from my RO unit, KH test kit tells me 0dKH. So it does seem the filter is somehow filtering carbonates or am I not understanding something? The resin filter says: "filtering limestone and calcium".
I tested the RO water TDS again today and it tells me: 17 ppm(0.7) - 12 ppm(0.5) - 26 μS

IMG_6569.jpg
 
Hi all,
Raw from the faucet, the API KH test kit tells me 2.5dKH. Water from my RO unit, KH test kit tells me 0dKH. So it does seem the filter is somehow filtering carbonates or am I not understanding something? The resin filter says: "filtering limestone and calcium".
I tested the RO water TDS again today and it tells me: 17 ppm(0.7) - 12 ppm(0.5) - 26 μS
That sounds fine. There is a good explanation of <"ion exchange resins"> from Lenntech.

cheers Darrel
 
Hi all,
.......... Should I assume the ppm in the water are mainly the Sodium ions released by the resin filter?

In any case if I read you right my RO water should be fine to prepare the dKH solution.
The cation is likely to be sodium (Na+), the anion could be chloride (Cl-) etc. I would have any worries about using the water to prepare your 4 dKH solution.

cheers Darrel
 
Something just struck me. What is the need of a 4dKH solution if tank water is let's say 0dKh (at least below 0.5dKH)? Wouldn't simply using RO water at 0 dKH in the drop checker and only adding some bromo blue be more representative of the tank CO2 content? Or am I missing something?
edit: in other words matching the dkh of the tank water to the dkh of the drop checker?
 
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Something just struck me. What is the need of a 4dKH solution if tank water is let's say 0dKh (at least below 0.5dKH)? Wouldn't simply using RO water at 0 dKH in the drop checker and only adding some bromo blue be more representative of the tank CO2 content? Or am I missing something?
edit: in other words matching the dkh of the tank water to the dkh of the drop checker?

Only because most of the CO2 colour charts are created based on 30ppm CO2 in 4dKH water. If the test water is a lower KH, it will just move more towards yellow at 30ppm CO2.

You could create your own custom chart for a lower dKH solution - though I can't imagine it would work well for 0dKH water which would probably be full yellow at very low CO2 levels - but there isn't really much point, as the difference between the KH of the tank water and test water isn't really relevant to the measurement of the dissolved CO2.

The reduction is the KH of the test solution is perhaps most useful if you have a specific dissolved CO2 target in mind. For example, if you wanted to target 15ppm CO2 instead of 30ppm, you could use 2dKH solution, and then aim for the same green colour in that as you would get with 30ppm and 4dKH solution.
 
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You could create your own custom chart for a lower dKH solution - though I can't imagine it would work well for 0dKH water which would probably be full yellow at very low CO2 levels - but there isn't really much point, as the difference between the KH of the tank water and test water isn't really relevant to the measurement of the dissolved CO2.

The reduction is the KH of the test solution is perhaps most useful if you have a specific dissolved CO2 target in mind. For example, if you wanted to target 15ppm CO2 instead of 30ppm, you could use 2dKH solution, and then aim for the same green colour in that as you would get with 30ppm and 4dKH solution.
Indeed. Not sure what I was thinking. Thanks for waking me up.

The reality is that I do not use the drop checker to quantify CO2 in my tank, instead I use the PH drop. The first and only reason I still use a drop checker is to simply make sure there is CO2 in the tank. That's it, nothing more. If I see it green or blue then I know either my CO2 bottle is empty or something funky happened with the reg or tubbing.
 
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