KH Question

[saugata]

Hi! All,

Is it possible to have the same KH value for tap water and the water in the aquarium injected with CO2?

Thanks in advance for your replies.

[vinz]

I'm not too sure what you are asking, but I'll try answering.

Injection of CO2 does not affect the KH. So it's completely possible for you tap water to have the same KH as your CO2 injected tank water.

However, if you do add supplements like baking soda to adjust your tank water's KH and yet still get the same KH as the tap water, then 2 things are possible:
1. Your KH test kit is faulty.
2. Your tap water's KH is not consistent.

[saugata]

Hi! Vinz,
Sorry for confusing you. Well, what I wanted to know is that will there be any impact on the KH incase I am adding CO2. To this you have already answered.

Now my next question is how do I get a relatively good idea of my tank pH. Currently I am using a Hanna digital pH meter but am not too sure about its reading. What I do is take some tank water in a cup and immerse the pH meter proble into it. I am getting a reading of 6. The KH is 6 thus, the tank CO2 level comes up to be 180 ppm which is impossible as the fishes are all ok without any signs of distress. Moreover, I have tried calibrating the pH meter by making fresh calibrating solutions for pH at 7 & pH at 4. Even then no change in the results. I have measured the KH using 3 different KH Test Kits viz., Azoo, Sera & Aquarium Pharmaceuticals but then again more or less the same result.

Can you give some idea as to what might eb going wrong?

[vinz]

I would trust the digital pH meter, especically since you've already calibrated it.

That leaves the KH test kits. As part of the trouble-shooting process, I will askif you are sure the kits gives readings in dKH, ppm CaCO3 or meq/L. There is a difference. You should be taking dKH readings.

You can check if they are working properly by testing a pail of water and noting it the results. Then raise the KH by a known amount by adding baking soda (or other supplment). Then test again to see if the results are as expected.

An alternative way to set your CO2 levels is to take a pH reading of your tank water at ambient CO2 levels and aim for a drop of 1.7pH to get the 30 to 40ppm CO2 level. See this thread for more details. Make sure you read the whole thread.

[saugata]

Thans a ton Vinz. Will try this out and let you know the outcome.

[saugata]

You can check if they are working properly by testing a pail of water and noting it the results. Then raise the KH by a known amount by adding baking soda (or other supplment). Then test again to see if the results are as expected.

Can you pl. explain this point a little more? How much baking soda to be put in how much water?

Looking forward to your reply.