I recently added some local rocks to my tank, hand picked off the top of our local mountain range in the Hudson Valley, the Shawangunk Mountains. The type of rock is a quartz conglomerate. Ive made some awesome caves with them and I'm very excited with the new addition to the tank. Of course I was very weary with using them as I really don't want to mess with my tank parameters, its a new tank probably 4 weeks into the cycle.
I asked my geologist friend if they might alter my ph. He said its mostly quartz and has very little carbonate in it, so it shouldn't. He also added that the water from my tap is run off from these exact rocks so the ph should match. I've been testing my ph daily to watch for changes from the rock but I've recently realized that the test kit is hard to read.
I'm using the liquid API kit.
My tap water is already high, Around 7.4 (on the regular ph test the color turns out to be blue with a slight tint of green).
My tank water is a clear blue on the regular ph test. (7.6+)
On the high ph test:
The tap water is a light brown, im guessing between 7.4 and 7.8.
The tank water is a darker brown than the tap, but its hard to tell exactly how brown, but has NO purple-ish tint. Its stayed consistent for the past 3 days, and I'm still monitoring. Somewhere around 8.0
The high range test is the only test where the color gradient isnt a smooth gradient, which is throwing me off.
My questions are:
Could an addition of rocks like this increase the ph to a point then level off?
What do you think of my ph currently, is it too high, and should I lower it, or will the effort to lower it be lost if I decide to keep these rocks in there? (I understand this depends what types of fish I want to stock. answer: general community fish)
Any comments on the API ph test kit?