SongCloud

I have 2 different indicators, one is from RedSea and the other 2 are from Azoo. Both state in their directions to use tank water in the units and add the reagent to it. I have done it this way the entire time that I have had them and I have found them both to be very reliable. For the most part, the reagent reacts for anywhere from 1-2 months for me, but I usually like to clean out the indicators every other month or so or else I find they can build up with slime or other stuff. Just adding my 2 cents to the thread.

Muirner

Ok, since you have 2 from Azoo, how bout you set up one of each, one with tank water and one with knowen KH solution. I dont get how putting tank water in would make it show you the co2? Do you put tank water in and then keep an air bubble trapped in the horn of the unit? Can you show me your setup? Hopefully tomorow i'll have time to rescape and scrape the glass and i'll take a few pictures of the way i have mine set up.

turbomkt

I can see how tank water will give you your pH, which you can couple with KH (not an exact measurement like known KH solution) but I doubt that it's anywhere close to as helpful as the known KH method. Known KH is literally "read the color and know your CO2 level as low, high or just right".

Squawkbert

^^Guys - Read #42 above.^^

Turbomkt - Right. pH/KH charts are not as accurate because KH is a measure of (just) carbonate hardness. Your tank has sources other than carbonate contributing to hardness, but your test kit for hardness can't discern carbonate hardness from all other possible sources of hardness, so it's not that accurate. Even if it were accurate, all you get is a point in time reading. You can't spot trends without a lot more testing. Drop checkers may be a little behind in terms of time, but where things have been vs. where they're going is quite valuable information (and they're more accurate than charts unless you have aquarium water that is unusually devoid of ion sources).

Blacksunshine

Best way is to use a soloution of known kH. using tank water introduces alot of variables to the soloution that won't read in the expected range properly.
I make ready to go regent as well as Drop checkers. And I've found in my testing of these things that using the known stable soloution is much more accurate and easier then trying to use tank water.

Dutch-AquaDesign

I have read this topic with much interest.
But I do have some questions...

1) Is the KH of 4 depended of my pH
So yes, what will it be for by example a pH of 7

2) How must be the KH when I want 25 ppm in my water?

3) Can someone explain me the calculations?

4) What are the exact ingrediënt of dKH water?

turbomkt

KH depends on your water source.

The goal here is to find a particular KH, that will indicate a particular color with the pH test agent (bromothymol blue). Targets are based on info like this.

4 and 5 dKH solutions give good targets for CO2 levels based on Estimative Index, etc. They are a combination of RO water and a reference solution to create the target of 4 or 5 dKH.

Dutch-AquaDesign

On this moment the pH=7 and the dKH=8 of my fish tank water (CO2=24 ppm)
Remark: My dKH is this high because I don’t use RO water in my fish tank.

When I understand this well, I still measure the pH value.
And the RO solution with pH reagent has a turning point of color at pH=6.6, no matter what.

So:
I need a RO solution with a dKH=4 to get a CO2=30 ppm, and do I need a RO solution with a dKH=3.6 to get a CO2= 27 ppm, no matter what.

Is this correct?


So the pH value of my fish tank has to drop to pH=6.6 directed by CO2 and will change my dKH automatic to dKH=3.6. Or is there more I need to do to get the right values?

Will this only work at a pH=6.6 or will this also work at an different pH value?
Do I need an other dKH of my RO solution when I have an different pH value?

Dutch-AquaDesign

I read a lot about a dKH=4

Is it necessary to use RO water (not pure) in my fish tank?
In my fish tank the dKH=8.

Can I use this test to see my co2 value is right?
Do I need an other dKH value in my tester?

Bert H

The drop checker needs kh4 water NOT tank water to do its job properly. If you're going to use tank water, you'll still be subjected to the same errors you had when you were just measuring kh/pH from the tank directly.

No. Unless you want to completely control the kh of your system and/or need softer water to grow the few 'soft water' plants.

Nothing wrong with that.

You can use the drop checker to measure your CO2 values, IF you use kh4 water in your drop checker.

You need water with kh4 for your drop checker.