# Adding 2 Sponge Filters enough to raise PH?



## Symplicity (Oct 14, 2011)

Hey All,

I added a double sponge filter driven by air pump and I think my pH is rising....
I was going to add a 2nd in my external breeder box but will it not drive it even further?

Going to retest my pH but according to my PH pen it is 6.9 .... versus the normal 6.5 ...

the ph liquid tests seem to remain the same @ 6.2ph ....

starting to think this ebay ph pen needs to be calibrated


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## getochkn (Jul 10, 2011)

A sponge filter shouldn't raise your pH unless your water is so still and devoid of O2 that it has a build up of C02 and the surface agitation is causing the CO2 to off-gas and raise the pH, but unless you are injecting CO2, have hundreds of fish, etc, the amount of CO2 in a still tank should be very, very little.

Do you stir your pH pen around and make sure it gets covered for a few mins? Do you keep your pH pen in a solution to prevent it from drying out?


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## matti2uude (Jan 10, 2009)

They are supposed to be calibrated once a month.


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## camboy012406 (Jun 11, 2010)

my ph pen gets lower compare to liquid


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## Symplicity (Oct 14, 2011)

Gonna read up on that calibration solution that came with the pen


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