This setup has been going for over 4 years now and with a master test kit and digital pH meter I’m getting a reading between 8.3-8.4. I have a few other tanks and they read about 7.8. About 7.6 coming out of the tap.
I will admittedly say that I have unsuccessfully kept discus in this tank. I didn’t have the heart to put anything else in it until I recently had a filter leak causing me to move the whole setup and it inspired me to get something in this tank.
I need to get the pH below 8 like my other tanks and I’m confused by the huge difference. The only thing I can think of is these rocks. I got them from a rock yard labeled as river rocks.
Posted by Krg_grand
3 Comments
River rocks are usually inert, but a good way to test them, is simply make up a bucket of water and test the water parameters, then add the stones and test parameters again over time to see if any changes.
What is the substrate? substrate is often the thing that raises ph
Did you clean, rinse, repeat and soak the stones. I have used large stones from the woods behind my house. They were plain sandstone slabs, porous rock, without problems. Wood has tannin in it, which is an acid. Which is were you want to be. 0=acid. 7=neutral. 14=alkaline
Those stone don’t look like they are or have a limestone component, which would be an alkaline. You could do some home experiments with drain cleaner and see if the rocks have a reaction. I am sure
there are videos on that experiment on YouTube.
You can test the rocks to see if they are reactive. The easier but less accurate way to do it is to use white/cleaning vinegar if you notice any fizzing the rock is probably releasing calcium carbonate and bringing up your pH.
White vinegar will miss some reactive rocks and the better way to do this is to hit the rock with 10% hydrochloric or sulfuric acid and see if they will fizz (You can use solution #1 in the API nitrate test kit it has hydrochloric acid in it)
The chemical free way is set out a bucket of tap water, then put your rocks into different buckets with fresh tap water and measure the pH over a 1 -2 week period to see if any of the buckets of rocks are (edit)raising your pH.
Outside of rocks upping your pH the other common culprit is crushed coral /oyster shell in the substrate, but i think that only usually gets pH into the high 7’s.
Fresh driftwood high in tanins can be used to drop you pH down by about 0.5 units if you are trying to get the pH lower