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Another DIY 4*dkh Solution

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Ok, so I decided to see if I could come up with another simple and somewhat accurate method to make 4* dkh for my co2 drop checker. This is what I came up with, I verified my results by duplicating the test 3 times and ending up at the same result each time.

Couple primers to start:
- I use my own RO/DI 0 tds water for the solution
- I use a calibrated HM Digital TDS meter
- I use API's Kh test kit
- I have used both Seachems Alkaline Buffer and Baking Soda and both test out the same
- I used everyday CLEAN containers and measuring cups/spoons that are used only for my tanks use and cleaned/rinsed with RO/DI water
- I do have lab testing background and have made very accurate 4* solutions but wanted to come up with another A.S. version for the casual hobbyist.
- No it will not be "laboratory" grade/accuracy but in my experience it is close enough for the casual hobbyist.
- I have been in the hobby for over 20 years but new to the forum

1. Start with 6 cups of 0 TDS water in a clean measuring container
2. Add 1/8 tspn Sodium Bicarbonate to the 6 cups of water and mix
3. Pour out 3 cups of this mix and discard
4. Add back 3 cups of 0 TDS water and mix
5. Pour out 3 cups of this mix and discard
6. Add back 3 cups of 0 TDS water and mix
7. Pour out 1 cup of this mix and discard
8. Add back 1 cup of 0 TDS water and mix
7. Water comes out to +/- 70 ppm TDS and will test @ 4* DKh solution

Any questions or comments welcomed. And if someone has the same basic matierals, I would like to hear if you were able to duplicate my results :)

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That is a very good method, even though I didn't try to check to see if it should be accurate. The good part is that everything is measured in large enough quantities to do accurately, and then it is just dilute, dilute, dilute. Lots of waste, but baking soda is cheap.

May I copy and paste this in the sticky in the fertilizing forum?
 

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Discussion Starter · #7 ·
Go right ahead Hoppy

And yes, quite a bit of waste water and overall solution when completed. But to err on the more accurate side is why I went with the amounts I did. One could half all these measurements and end up with less waste/product, but as mentioned I prefer to work in larger quantities.
 

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New guy question?? Is RO , distilled and 0 TDS water the same? Does the "quality" of distilled water vary?
If I'm totally confused please feel free to correct me. I'm confused a lot these days!!!
Love the method as it sounds so much better and more workable for me.
 

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RO/DI (reverse osmosis/deionized) water is about the same as distilled water - you probably couldn't detect the difference. Zero TDS (total dissolved solids) is a measure of what is in the water, not a method for achieving that - distilled or RO/DI will very likely be 0 TDS. The goal with making a KH standard solution is to have nothing in it that affects pH except carbonates/bicarbonates and CO2. Distilled or RO/DI would both work, assuming they were properly done. And, if they aren't perfect, the water is still good enough for what we need.
 

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For over 11 years I have worked as a lab analyst at an environmental testing lab. When I first started working at the lab we would make our own DI water, but we started having some issues (can't remember what they were) and so we started to just use store bought distilled water instead of making our own DI. We also use jugs of water that is labeled purified water as it is the same as distilled. We have used both name brand and store brand, and I have never noticed a difference in the quality.
 

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Thanks for the info. Sometimes I had assumed that to be the case but then I find I need to check things and not just take while APPEARS to be right. I think I will do this and check the two solutions against each other. My first attempt at using weight seemed to have sever choices where the best I could get was "close nuff". Don't really like to work that way even though I know that the final color answer is still just an estimate to figure in with other information.
 

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Discussion Starter · #14 ·
Glad to hear you will give it a shot!

But mind that unless you are able to verify that you are starting at 0 tds or damn close, results cannot be guaranteed. I found that if tds rose to around 74-76, it threw of the dkh slightly.

When I was working in a lake biology lab, seemed they would get lazy on the ro filter maintanance. Wonder if that's what issues your lab had also, Lol.
Sent from my Kindle Fire using Tapatalk 2
 

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Quote "results cannot be guaranteed."

I have found that in this hobby, that is part of the challenge! If I find some advise of this sort which IS guaranteed, I tend to suspect the offering!!! Waaay too many options for screwing up the process.

Thanks again and I will offer up what different results I may find.

Just one of many small decisions to think over.
 

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nice job, i have a question, is the solution that came with the drop checker is 4dKH solution?? and u suggesting us to make this solution so if the solution that came with the drop checker is done using we can use this diy solution........... or do we need to add this solution with the one that came in the package im new in drop checker, bought one last week but dont know how to use :p hope to get some suggestion
 

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I'm not sure what comes with the drop checker. Never bought one. But this is to make a solution that is 4dKH. Then we need to add the "PH indicator solution" Which comes with API test kits. That turns the solution blue. When exposed to the CO2 coming off the water, the blue will slowly turn yellow if CO2 is low or green if near the 30PPM we consider correct. There are several items here that will explain far better but it may take some searching to find them.

Any directions with the drop checker? Seems they should tell you something like that!!!
 
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