# Co2 and kh issue



## Tarobot (Jun 27, 2010)

Ive recently started dosing excel and flourish in my 2g and 5g and though i read co2 will lower kh i found my kh to be higher than before. Ph is 7 and gh about 80ppm. Its hard to measure the perfect ml for dosing cause the tanks are so small so overdosing is more likely than not. Im just wondering why my kh has risen. Thanks in advance.


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## Captured Moments (Apr 22, 2010)

My understanding is that injecting Co2 into a tank does not affect KH so it doesn't lower or raise it. The Co2 does affect PH level with the result dependent on the KH level. Are you using anything to change the KH level in your tank? perhaps it is creeping up because of something else in the tank (substrate, shells).


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## Tarobot (Jun 27, 2010)

Fluval shrimp stratum. Driftwood. Java fern. I have the seachem acid buffer but havent used in since the tanks were setup over a month ago.


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## Captured Moments (Apr 22, 2010)

That's interesting then. I never tried the Fluval Shrimp stratum substrate but I highly doubt that it would be cause of it and on the contrary may help swing the KH to the lower side. What is your KH level at now? maybe your test kit is innacurate or your water supply keep changing, like everytime you change water, it is at a different KH level. In any event, I wouldn't worry too much about it as long as your PH is fine.


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## 2wheelsx2 (Apr 21, 2010)

Well it doesn't sound like it's a CO2 problem since you're not using CO2. You're dosing Excel which is a carbon source, but not a CO2 carbon source. So it's something else in your tank. You mention your readings afterwards, but what was your reading before?


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## Tarobot (Jun 27, 2010)

ph and gh has not changed from before all the dosing. only the kh has gone up, kh used to be the same as gh at around 80ppm but now it's around 120.


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## neven (May 15, 2010)

have you tried an alternate KH test to make sure your test reagent is showing you the correct result? Changes in KH result in PH changing aswell, unless you inject CO2 gas (which you do not, or acid buffer periodically). What you are seeing is a minimal shift in KH, if it keeps rising, then perhaps theres something in your filter media buffering the water up, or some stones in the tank that are doing the same. As long as your PH remains close to 7, i dont see why you should worry.

On the comment about not being able to dose accurately, I have a solution for you. If you got a spare container, you can measure out equal parts distilled water and excel/flourish and combine them in the container. This will allow you to double the volume you dose to make measuring easier.

Since you are using 2 liquids for dosing, try going to a pharmacy and buying 2 infant medicine syringes. They are 10 mL and come with a rubber stopper (save on foods/pricemart has them). You can put airline tubing in the rubber stopper's narrow side to run to the bottom of the bottles and use the rubber stopper as the cap, this way you can draw right out of the bottles without even taking the cap off or tipping the bottles.

they syringes look like this: (but the rubber stopper has a little plug to seal it)


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## 2wheelsx2 (Apr 21, 2010)

Tarobot said:


> ph and gh has not changed from before all the dosing. only the kh has gone up, kh used to be the same as gh at around 80ppm but now it's around 120.


That tells me there is some minor amount of carbonates being dissolved. 80 to 120 is not a huge increase...about 2 degrees. The fact that you're starting at 80 tells me there is already some carbonate in your system, since our water is usually at about 20 - 50 ppm TDS.


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