Re: Mystery Tank

> From: RicCooney at aol_com
> Date: Mon, 16 Dec 1996 12:13:24 -0500
> Hi all, hopefully you all can shed some light on this mystery. We have
> a 52g tank set up over a year. Two weeks ago we noticed that the co2
> level was 50ppm. Quite high we thought so we cut off the DIY yeast
> engine. We are doing weekly 15% water changes with DI water enhanced
> with trace elements(Electro-Right)and pH adjuster. The co2 has always
> been in the 5ppm range. This week we also added PMDD enstead of the
> Kent fertilizer we were using. Yesterday we got the following:
> CO2	>100ppm
> pH    6.7
> dKH	5
> We measured the co2 with both a LaMotte and a Tetra test kit.  Can
> anyone suggest what is going on with the CO2.
That's bizarre, all right.

Are you sure that your test results are correct?  CO2/pH/KH don't
match at all.  pH 6.7 and KH 5 indicates CO2 = 30 ppm.  What kind of
pH adjuster are you using?  What have you done recently that would
goof up the CO2 readings?  

Other strong acids or buffers in the water can affect the CO2 test kit
since it is basically titrating the sample with sodium hydroxide and
watching for a specific pH end point.  The Tetra test kit does not
return a value, does it?  Just "too low, too high"?

Put some of your tank water in a glass and shake it or aerate it for
awhile to drive out the CO2 and then test the CO2 levels.  Still high?
If yes, something is messing with the CO2 test. 

Are your fish breathing hard?  If not, I would not believe the pH
levels the tests have reported.