# RedSea Co2 Indicator Question



## FreakIndeed (Jun 17, 2007)

Can I prepare water with a KH of 4 and use it with the RedSea Indicator's solution or should I only use the RedSea's container and instead use Aquarium Pharmaceuticals PH test solution?

Thanks!


----------



## hoppycalif (Apr 7, 2005)

I know that API's test kit uses bromothymol blue as the indicator dye. I don't know for sure what the Red Sea indicator dye is, so I prefer to use the API solution. You can prepare a 4 dKH solution, but you have to use distilled or deionized water when you do that. It won't work if you use tap water.


----------



## FreakIndeed (Jun 17, 2007)

Thanks Hoppy, I bought two testers so I guess I'll do a little test, one with the Red Sea and one with API PH solution. I did see another post by you when I searched, explaining how to create the KH=4 water. Very insightful. Thanks again.


----------



## Left C (Jun 14, 2005)

I've used the API pH indicator fluid, the Sera CO2 indicator fluid and the Red Sea CO2 indicator fluid. They work fine. They all use Bromothymol Blue as the CO2/pH indicator fluid.


----------



## FreakIndeed (Jun 17, 2007)

Thanks Left C, that's good to know!


----------



## Left C (Jun 14, 2005)

You're very welcome, FreakIndeed

You can purchase a known 4 dKH from: http://liquidarthome.net/khstandard

I made my own using these instructions:



billionzz said:


> KH standards
> 
> Here is the information needed to make a KH standard. When I started using the drop checker method for measuring CO2 there was a lot of confusion as to the proper way to make a KH standard. After a lot of searching and asking questions I found the correct way to make a good KH standard.
> 
> ...


This is from: http://www.plantedtank.net/forums/newreply.php?do=newreply&p=374058


----------



## FreakIndeed (Jun 17, 2007)

I got setup today. I'm getting my distilled water tonight for my drop checker. However, I've got the Co2 up and running. Does anyone know of a general ballpark on what I should be aiming for as far as bubbles per second here? It's a 90 gallon with a 250 watt Metal Halide light. I have swords, crypts, anubias, sags, and vals.

How quickly should I see my PH dropping on the PH meter? It's been about 30 minutes and it's dropped from 8.0 to 7.7. I've got my Co2 going into the intake on my Rena XP3. I'm currently at about 5 bubbles per second.

Thanks!


----------



## hoppycalif (Apr 7, 2005)

If the pH drops by 1.0 from what a sample of tap water has, after it sits around for a couple of days, you will be unlikely to have too much CO2 in the tank. How fast it drops on the pH meter depends mostly on how you are introducing it to the tank, how much surface water disturbance you have, how much water circulation you have in the tank, and, the bubble rate.


----------

