Problem with too much CO2

[pairustwo]

I have been trying to tweak my DIY CO2 system because I can't get consistent and or good levels of CO2 out of it.

Last night I ditched Champagne yeast and tried regular bread yeast. I was getting 30 bubbles per minute within a couple of hours and today I came home and am getting more bubbles than I can count pouring through my bubble counter. Great.

However my drop checker is yellow so I checked my pH and Kh. My pH is yellow, like 6.0 yellow. I don't know what color it would be if it were lower than 6.0 (this is an AP test kit). My kh is 5 degrees. Which is weird for two reasons. One is that my kh is usually 3 degrees and second that looks like 150 ppm of CO2 according to Chucks Calculator.

I checked my kh in a 5mil tube (3 drops to change to yellow) and in a 10 mil beaker (10 drops to change to yellow).

Oh yeah, and none of my fish are dead.
I turned my reactor to face the surface so hopefully most CO2 will bubble to the top until I can figure out what is happening.

What on earth would make my kh rise like that? And I didn't add any baking soda!!!

Please help.
Pairustwo
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[hashbaz]

What kind of rocks and substrate do you have?

Sometimes the the acid formed by CO2 will disolve calcium carbonate (or something like that?) that is already in your tank.

 

[pairustwo]

I have flourite substrate.

But I did add some crushed coral some time ago hoping to stabilize my pH. At the time my Ph was sinking really low for some unknown reason (this was before I added CO2) and my kh was 1 so I was trying to make the water harder. It rose to 2 degrees kh. I also took out a piece of driftwood (1 of 2 pieces) and the pH seem to stabilize at 7.

Now you think that the carbonite is dissolving off the coral?

In any event I am getting way to much CO2. now the water in my tank is close to the water in my drop checker and they both say I'm off the chart with CO2

At what level do fish start dying? My fish aren't even gasping for air.

 

[Purrbox]

High levels of CO2 would cause the Crushed Coral to dissolve faster raising your KH.

Normally it's somewhere above 100ppm of CO2 that your fish are in danger. I'd recommend running a quick double check on your water to ensure that nothing has been introduced to the tank to throw off the pH/KH relationship. Take a sample of tank water and either let it sit for 24hrs or aerate it for an hour with an airstone to allow all the CO2 to gas off. Test the sample for KH and pH. You should get results of approximately 3ppm. If not this could explain why your fish are not acting stressed. The fact that your fish aren't acting stressed yet is a good indication that your CO2 levels aren't quite as high as they appear.