How to make a reference KH solution for CO2 measurement

[7Enigma]

Just wanted to ask how the indicator works as a function of air gap. I normally try to fill up the Red Sea unit with my 4 degree KH solution and 6 drops of pH indicator leaving as little air as possible. Would it react faster if I had less liquid and more air? I also remove most of the air underneath the Red Sea unit by tilting it sideways to let the large bubble out.

[dapellegrini]

I have heard that putting LESS kH solution in the drop checker will help it equalize faster. So instead of filling it all the way, fill it like half way. Reducing the air gap may also help, but I think the biggest savings is in reducing the quantity of liquid in the drop checker.

I will let someone else perhaps reply with more details on why this is so.

[7Enigma]

Originally Posted by dapellegrini

I have heard that putting LESS kH solution in the drop checker will help it equalize faster. So instead of filling it all the way, fill it like half way. Reducing the air gap may also help, but I think the biggest savings is in reducing the quantity of liquid in the drop checker.

I will let someone else perhaps reply with more details on why this is so.

Thanks for the reply. I think I'll be trying this out in the near future. Right now it seems to take FOREVER to get a change and it isn't always back to "normal" in the morning even though the CO2 has been off since 11pm the night before (7-8hours).

[dapellegrini]

I have also heard that some non-glass drop checkers can leak tank water into the test solution. The one-piece glass ones will definitely not do this to you.

[rkilling1]

Originally Posted by 7Enigma

Thanks for the reply. I think I'll be trying this out in the near future. Right now it seems to take FOREVER to get a change and it isn't always back to "normal" in the morning even though the CO2 has been off since 11pm the night before (7-8hours).

Mine do the same thing, but how do you know that the fish tank is really at it's 'normal' CO2 level in the morning?

During PWC's, my drop checkers go blue and within an hour of refilling the tanks, the solution is back to green. This indicates to me that the drop checker (rea sea one) is working properly and has a reaction time of about an hour. And just like yours, mine remain green all night long.

I would have to say that my CO2 is staying around 30 PPM during the night cycle. We (planted guys) have a lot of plants in our tanks adding CO2 to the water column at night (let alone the fish). How much CO2 is added by plants? I have no idea, but I do know that my CO2 system is off and I can maintain ~30PPM CO2 during the night.

[brutus]

if drop checker changes colour from blue to green when co2 at right level in tank why put 4 kh souluton in it if tank water is 5 kh ? wont that give me false reading?

[Purrbox]

The point of the drop checker is to remove the variables of aquarium water. While your tank water may be 5 dKH, what if there are other variables that throw off the pH/KH relationship? Further what if something happens that slowly changes your pH/KH other than the CO2 injection that you don't notice? Further many people don't have water with dKH within the range that allows green to be an indication of 30ppm of CO2. With a KH of 5 dKH your indicator is actually showing higher than 30ppm CO2 when it turns green. While it's still a good number and not so high as to cause problems, it isn't 30ppm. By using the reference solution you remove these variables.

[brutus]

tnks purrbox i think i finally understand will try and make some to use also ..I just checked my ph and kh and showed around 15 ppm but drop checker shows very light green colour almost yellow.