Drop Checkers - How They Work

[rdstars]

It's ok I bought the complete drop checker from the LFS, been checking it against my test kit and so far it's accurate.

Just need to figure out my planting next.

 

[aaronnorth]

ok, you are using 4dkh and not tank water aren't you?

Thanks, Aaron

 

[rdstars]

The instructions said use tank water so that's what I went with, started off with about PH 6.8-7. It changed colour just like doing it with the test kit and since playing with my DIY CO2 and amount of Air Stones in the tank ( as in Ive taken one away and using a single Air Pump ) it has changed in colour accordingly ( gone a lighter shade of green ), also rechecked with the test kits and seems to match the results.

 

[aaronnorth]

That means you are just testing the pH of the water.

It is important that you use 4dkh or 5dkh solution, DO NOT use aquarium water, as this contains other acidic substances, which can affect the reading (hence why the ph/ kh CO2 tables are inaccurate!)


As the CO2 gasses off from the aquarium into the drop checker, the ph lowers due to the carbonic acids formed by CO2 when it dissolves in water. When the drop checker turns from blue, to green, this indicates a pH of 6.6, and because we know the solution is 4dkh, this tells us we have approximately 30ppm of CO2 in our tank water.

Say your tank water is pH7, KH4 without injecting CO2
this would equate to 30ppm CO2, how is that possible without even injecting any CO2!?

This is why we need to have a known reference, so we can be sure of the pH change is due to the carbonic acids being formed.

Thanks, Aaron

 

[rdstars]

That was about a day after I started the CO2, not 100% on all this CO2 and plants as its all new to me but had to go along with what I could find out at the time.

Should I maybe buy some kdh4 and set the drop checker back up?


Just done a PH test and it's about 6.6

 

[Haveagojoe]

I am now confused, in the origanal post it gives a link to an ebay site (which I have bought of before) for a cheap drop checker, on there they say to add to the solution a small amount of aquarium water but in the original post it says do not do this, so which way do i go, I have ordered that drop checker with the test solution so what do I do?. I am not a chemist and am mainly going on the excellent advice that is given on here, but I am confused.

 

[rdstars]

I've been checking my drop checker colour and doing the long winded test with my original test kit and so far they are matching, I got a constant aprox 6.6 ph.

I have not checked my Nitrite, Nitrate or Amonia in ages as I have a mature tank, regular water changes and don't get problems with fish BUT thought I will test them today, they were all so low it was hard to see if they were above 0 on all of them fractional that's about it. I still remember the days of daily testing and water changes trying to get the tank stable BUT it is so nice to have it all mature now.

 

[aaronnorth]

I am now confused, in the origanal post it gives a link to an ebay site (which I have bought of before) for a cheap drop checker, on there they say to add to the solution a small amount of aquarium water but in the original post it says do not do this, so which way do i go, I have ordered that drop checker with the test solution so what do I do?. I am not a chemist and am mainly going on the excellent advice that is given on here, but I am confused.

Add 4dKH solution, I know I am going to say that as it is my guide lol so you can wait for someone else to reply if you like

Thanks, Aaron

 

[soc200]

Add 6g of pure Sodium Bicarbonate to 5l of DeIonised water (DI) to give you a solution at 40dKH.

Mix 10ml of this solution with 90ml of 'fresh' DI to give you 1l of 4dKH reference solution.

10mL + 90mL does not equal 1L. Did the original poster mean to put 100mL? I'm tempted to assume that 100mL of the 40dKH + 900mL of distilled water would make 1L of 4dKH. Am I crazy or did I miss something? I would appreciate any advise.

 

[aaronnorth]

I'm sure thats been pointed out before and I'd changed it lol? hmmm

well it is supposed to read 100ml + 900ml,
but it doesnt matter too much as it would still give you 4dkh

I've added a bit on scaling down the production too.

Thanks! Aaron.

 

[SuperColey1]

Add 4dKH solution, I know I am going to say that as it is my guide lol so you can wait for someone else to reply if you like

+1 4dKH gives you an uncontaimnated reading to register 30ppm at nice green. Tank water gives a contaminated reading as the acids in the tank water plus all sorts of other stuff will alter the Ph of the aquarium.

Think about it. what is the Ph from your tap? What is the Ph of your tank water? Is it the same? Something is altering the Ph. We don't want any reading to be altered by anything other than CO2.

AC