Low Ph

Rorie · Sep 6, 2011

I have tested my PH in my show tank and posted my shock at the result before. But i alway thought it was due to my CO2. But now there is no CO2 connected (i ran out!). I have done a 50% water change as i do every week. Just checked the PH and its 3.9!

I know the first question....is my digital PH reader calibrated? Yup. Just calibrated it with PH 4 and PH 7.

My tnak has ADA substrate which i know is designed to lower the PH a bit...but surely not this amount?! I dont have any peat or anything in the water, i dont use buffers, nothing. My tap water is soft, but not this soft!

So, any ideas what could be causing it?

TwoTankAmin · Sep 6, 2011

What is your KH? Low KH will allow the pH to drop easily and quickly.

StandbySetting · Sep 7, 2011

Digital pH reader? Try testing with a liquid test kit instead, my money would be on the digital pH reader being out.

Rorie · Sep 7, 2011

yeh KH 2. How can i raise this?

The digital PH meter is accurate - test it often with buffer, and all my other tanks which have a much more predictable ph.

So, any suggestions?

TwoTankAmin · Sep 9, 2011

To raise both GH and KH simultaneously, add calcium carbonate (CaCO[sub]3[/sub]). 1/2 teaspoon per 100 liters of water will increase both the KH and GH by about 1-2 dH. Alternatively, add some sea shells, coral, limestone, marble chips, etc. to your filter. To raise the KH without raising the GH, add sodium bicarbonate (NaHCO[sub]3[/sub]), commonly known as baking soda. 1/2 teaspoon per 100 Liters raises the KH by about 1 dH. Sodium bicarbonate drives the pH towards an equilibrium value of 8.2.

I have used both. The baking soda will definitely effect pH. You can try adding a bag of crushed coral to a filter. For a 40-50 gal tank the amount to try is between 1/2 and 1 cup of coral. It will take some time for it ti have an effect. You will have to test to see how much gets you to where you want to be. Over time the coral will dissolve and you will need to replenish it.