PH question

[duanes]

If any of the rocks is limestone, that rock can raise pH.
If the sand was mined at a place containing dolomite rock, or limestone, pH can rise.
When I was a water plant chemist, the pH of our influent would rise during lake turnover, or during a storm, and raise the tap water pH a bit. Tap water pH can fluctuate with the seasons.
I would also check the expiration dates on your test reagents, a nitrate reading of 0.00 is uncommon, unless you're overgrown with plants. And if you are overgrown with plants, your pH should be lower in the morning, and higher in the evening.

 

[Lark]

If it helps any, it's a newish (as in, straight from the pet store), two month old tank that is undercrowded. Sand is silica based. The expiration date on the test solutions is 09/2017. The tank has two modified overhead Aqueon 55/75 filters, with the modified bits being a prefilter and a chamber big enough to include bio balls. The river rocks were the pre-bagged stuff that can also be found at any pet store.

When I last took that 0.00 rating it was around 5pm, which was yesterday.

 

[erk419]

If it helps any, it's a newish (as in, straight from the pet store), two month old tank that is undercrowded. Sand is silica based. The expiration date on the test solutions is 09/2017. The tank has two modified overhead Aqueon 55/75 filters, with the modified bits being a prefilter and a chamber big enough to include bio balls. The river rocks were the pre-bagged stuff that can also be found at any pet store.

When I last took that 0.00 rating it was around 5pm, which was yesterday.

What test kit are you using.

 

[Lark]

API Freshwater Master Test Kit

Just tested the Nitrate again, 9pm and 2 hours after feeding fish, and if I squinted real hard I got a rating of 5.0ppm. Both Nitrite and Ammonia still at 0. pH was still 8.0

Good news for me I guess is that if I get some bogwood to hopefully lower the pH I'd have the ideal tank for discus.

 

[duanes]

Have you been doing partial water changes, or just adding water to replace evaporation loss?

 

[Lark]

I've been doing both, actually. 30% water change per week, along with vacuuming the gravel, then at least once in the middle of the week I'll top off the water. The water level is usually right at the level where the glass meets the top frame, so its more noticeable when I get a lot of evaporation; I do it this way to give the bichir in the tank some surface breathing space.

Somebody at another forum suggested that the reason why there is such a difference in pH between my tap water and tank water is because I hadn't let the tap water sit in the test tube long enough before putting in the test solution. Something the little instructional booklet that comes with the test kit failed to mention.

I left the tap water in a test tube for a couple hours, tested it again, and now the difference is just around a 0.2, basically hovering around 7.8 - 8.0. So, there's that.

 

[erk419]

I've never heard about letting it sat in the tube for awhile before adding the chemical, makes since though gonna try that and see what readings I get.


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[duanes]

You do not want to let in sit in the tube more time than it takes to read the pH reaction. pH in brief, is measuring the hydrogen ion content in water, and this changes as water sits, and would give a false reading. Acids ..ie sufuric acid, H2SO4. 2 Hydrogen atoms in combination with 4 sulfate
Another suggestion...
If you add more water than you change (as in a top off the middle of the week), the mineral content of the water can build up, this buildup can raise your pH, and be one of the reasons the tap is lower than the tank water.

 

[duanes]

You do not want to let in sit in the tube more time than it takes to read the pH reaction. pH in brief, is measuring the hydrogen ion content in water, and this changes as water sits, and would give a false reading. Acids ..ie sulfuric acid, H2SO4. 2 Hydrogen atoms in combination with a sulfate ion.
Another suggestion...
If you add more water than you change (as in a top off the middle of the week), the mineral content of the water can build up, this buildup can raise your pH, and be one of the reasons the tap is lower than the tank water.

 

[Drstrangelove]

Is this article correct? http://www.ratemyfishtank.com/articles/107

The pH from the tap is actually higher than it says if you test it immediately out of the tap. The 'sitting' issue is that tap water often has dissolved CO2 which lowers pH readings, so the 'true' pH goes up as the CO2 is released during gas exchanges. This article suggests using an air stone to aerate the water awhile before taking the reading (in the tube.) That may be the 'sitting' part.

Either way, at such high pH's, some chemicals effects are amplified at pH readings above 7.0. Driftwood in the tank may lower the pH over time, but if water changes are being made with water that has a very different pH than the water that is in the tank, there are some people that think it can cause stress on the fish. That combined with normally higher pH readings and chemicals can be fairly much a concern.

For example, I thought that copper based medicines are dramatically more potent at higher pHs.

http://guppyplace.tripod.com/WaterQuality.html Second article