Pure quartz (as used in a scientific lab) is innocuous, as it is but a form of glass, silicone dioxide, without certain impurities typical glass has. If I recall correctly. I can't imagine it affecting pH or TDS whatsoever.
Now if it came from the wild or other random source and has impurities that you don't know about, that could be gambling. If you suspect it has iron specks, I'd probably not use it because iron itself is a heavy metal that's toxic to living organisms, fish included and like most heavy metals has been associated with tumors. Of course, iron effect, toxic or not, depends on concentration.
Overall, your case remains an enigma to me, as the cause of the pH drift from 7.5 to 8.8 remains unknown. The causal logic says if all had been fine and dandy until you added the quartz implicates the said noble glass mineral.
BTW, 8.8 is the highest number an API f/w high range pH test can measure. So in theory, it may be even higher.
A reliable electronic TDS meter can be found for as cheap as $50, mine is anyway.
Duanes, a pH change of 2... does it not equal the factor of 100, if one chose to be a pedantic and annoying wise guy?
0 on our kits isnt truly 0. I used to have a reef and for a long period of the time on a standard test it would be 0 or the color of 0 nitrate. I found that to be extremely unhealthy for the corals 10 to 15 was a much healthier environment. As for fresh I have a friend with a tank on a drip his tests at 0 all the time on a standard test. He also is a biologist at a water treatment plant and in reality he said his 0 is more likely in the 40s. So like I said 0 really isnt 0 and if you are just changing water to get those results its more likley your BB is getting starved but if everything else checks out and contiunes to check out why worry.....as long as you keep the status quoe you will be fine.
Right. As I have been parroting after MY friend, from UK, a professor and lab head of wastewater treatment Darryl from Planet Catfish, home tests for nitrate can give a relative indication. They suffer from too many other anions badly, real badly interfering with measuring NO3-. They measure nitrate accurately in distilled water. Anything short of that - forget it. A zero can be even a 100 ppm. Good thing the nitrate toxicity is the thousands.
Good thing to have friends in the high circles of the dark underworld of wastewater treatment.