It's possible plants and fish don't mind a pH drop as much if it accompanied by a CO2 increase, since this is the pattern in the wild. pH drop with CO2 not real? No. Just possibly not as stressful.
If your rocks pass the acid test, I doubt they're screwing up any chemistry. They look like inert quartzite in the photos, though of course it's hard to be sure. You can try some concentrated hydrochloric acid in place of vinegar (available in any decent hardware store, often as "muriatic acid") and if that doesn't fizz they will not alter chemistry of water. The one on the left looks particularly "inert" to me; the one on the right looks like it might have some calcite crust.
Boiling them to clean is not a bad idea. This won't destroy some cysts and spores, though, so if you're really concerned about that (and I actually doubt it's a problem) then you need a sporocide. Concentrated bleach works and is (relatively) innocuous to handle.
This is reassuring, thank you. After more testing today (see below), I'm as confused as ever and may run out to get some muriatic acid. I was using phosphoric which I believe is a stronger acid than vinegar, but not as acidic as hydrochloric.
Originally Posted by Desert Pupfish
Are you able to access your water before it enters the whole house system? If so, you could test your rocks in that environment to see what happens. If you're starting with softer water, the stones may not affect it as much--provided you're doing regular water changes.
And if it does harden the water, unless you & your daughter have your hearts set on particular fish or plants that require soft water, there are still plenty of beautiful fish & plants that thrive in harder water. (As you well know if you had African cichlids) Or you can just forego the rocks, and can still create a beautiful tank with beautiful local manzanita and all the soft water-loving fish & plants you want.
Look forward to seeing what you create
Thank you for this reasonable advice. I can
bypass the acid neutralization system, and I may. Again, my big concern with adding the Calcite was to raise the pH and hardness of my 6.0 pH well water, which I was concerned would become dangerously acidic in an aquarium with increased CO2, bioload, etc (not to mention my concern for my home's metal pluimbing!). But the advice in these forums suggests to me that it's not that simple and there are many other variables to consider. And yes, I have some our local manzanita and madrone curing right now. Beautiful, indeed!
Sounds like that calcite system will add only calcium to water. You would probably be better off pulling water from before that system and using something like Seachem Equilibrium to bring GH up a bit. With only extra Ca in water the balance of other macro needed in healthy aquarium water is being ignored. Or maybe 1part calcified water to 3 parts water treated with touch of Equilibrium.
Amounts per 1 g
Soluble Potash (K2O) 23.0%
Calcium (Ca) 8.06%
Magnesium (Mg) 2.41%
Iron (Fe) 0.11%
Manganese (Mn) 0.06%
Very interesting. I had not even considered that imbalance coming out of my tap at all. Suddenly it seems an obvious oversight. Thank you! I will likely dial back the Calcite contribution a bit or entirely and/or consider a product like Equilibrium.
What is the GH KH of your well water? If you put a glass of well water on the shelf and check it 2 days later does the pH drop? Typically when you have soft acidic well water the The low PH might be due to high levels of CO2 in the water. Once the CO2 has outgassed the PH may increase. In some cases there may be too much CO2 in the water causing animals in the tank to suffocate. So you might want to put enough well water in a bucket for a water change and let it site for a week and than at the next water change use the water in from the bucket instead of straight well water. The degassed bucket water might be less strssfull to the fish than using straight well water.
I can't say that using your well water straight or degassed is better than using the water that has been through the calcite filtered water. Ideally you want a mix of magnesium and calcium in the water plants need both of these minerals for proper growth There is some information that suggests too much calcium could interfere with plant growth. You might want to consider using Dolomite instead of calcite. Domolite Is a mineral with both calcium and magnesium carbonate in it.
Calcium carbonate dissolves in acidic water but it does not dissolve in water with a PH higher than 7. This lack of solubility at a PH above 7 generally causes thePH to stabilize at 7. It should not go to 8 as you observed in the water from your boiled rocks is a little strange unless heating caused something else to dissolve that might not normally dissolve in unheated water. It is hard to say if those rocks are OK or not. Generally the safest rocks to uses are granite rock or lava rock that has been exposed to rain over many years.The rain tends to wash off any water soluble minerals making the rock mostly inert. Beach sand is also a good material to use because water exposure has also made it inert.
These is a lab test called TCP-OES that can measure 33 element in water It can measure 13 of the 14 plant nutrients in water. The 14 nutrient is nitrogen which this test cannot detect but is easily tested for in liquid test kits. This test cost $30 dollars and take a week to ge the results and can measure the consntration in the water down to 0.001ppm. You could use this test to see how there water chemistry changed when you boiled the rocks. This test can also be used to verify all nutrients plants need to grow are present. If plants are missing just one or more of the 14 needs nutrients plant goth could slow or stop growing and algae could take over the tank.
Great information. Thank you! As suggested above, I've had the two types of rock in separate room temperature water for 48 hours and I just tested them both against a tap water sample:
TAP WATER (after Calcite "filter")
ROCK 1 BUCKET
ROCK 2 BUCKET
, looking at these numbers I was beginning to suspect that yeah, maybe the rocks are just not appropriate for the aquarium. As you suggest, CaCO3 should not contribute to a pH higher than 7, and it didn't until I added either rock
. While the heating of the rocks raised it even higher, the room temperature soak, too, raised the parameters significantly. So it must be the rocks, right? For whatever reason, though, I refuse to believe it, LOL! I'm still not satisfied, at least not yet. So, I got to thinking, maybe there are undissolved solids coming out of the tap or something, that are invisible to me, but which "dissolve" if left to sit for a certain period of time, thus changing the water chemistry. And now, you suggest (which kinda blows my mind!) that high concentrations of CO2 in well water are not only potentially toxic to fish, but that degassed CO2 could/should result in a pH rise. So, is it possible that the rise in pH (and/or GH or KH) I'm seeing in my rock-filled buckets after 48 hours could be due to these factors? Degassing and/or dissolving? I was starting to think along these lines when I decided to leave a sample of tap water to sit for seven hours and tested it against a fresh tap water sample: They were pretty much identical. But maybe I just didn't let it sit long enough
...? Well, I'm going to find out. I'll let a bucket of straight tap water sit for a week and test before and after. Thanks so much for this idea!
Again, thank you all for your generous advice and for sharing your experience. I'm learning so much and am very grateful!