[nchmi28]

My filtered tap water has a pH of 7.6. & GH of 150ppm. When put in my tank with Eco-complete, Silica sand, drift wood, 1 large black rock and a few dozen black river rocks the pH went up to 8.4 and the GH is at 300ppm (using strips for GH, 300 is the highest they test to). I decided to test the large rock, river rocks, and sand separately. I let them sit in new water over night and tested them in the morning. Large rock: pH 8.2, GH 150ppm; River rock: pH 8.4, Gh 300ppm; Sand pH 8.2, GH slightly lower than 300ppm.
I am very confused. I thought that silica sand is supposed to be inert. I asked my father in law (who is a retired chemist, but knows nothing of fish keeping) and he said there must be something, possibly calcium, in the sand. Does this sound right to anyone else? Has anyone else experienced silica sand raising their pH?
In this tank I'm hoping to keep kuhli loaches and a pea puffer. "Seriously Fish" says the pH for kuhli loaches should be 3.5 – 7.0 and 6.8 – 8.0. for the pea puffer. I'm actually more concerned about the pea puffer, since I've never kept them before and they seem to be more sensitive. Do you think the fish will be okay in the higher pH? I don't want to do anything, beyond the initial setup, to continuously alter the ph (like adding peat, or chemical pH down).

 

[Nordic]

Puffers need a pristine matured tank. Don't rush into it

 

[nchmi28]

Puffers need a pristine matured tank. Don't rush into it

I'm planning on waiting a few weeks minimum before adding any fish. When the tank is ready I'm going to get the kuhli loaches first, then let them have the tank to themselves for awhile. This will let them settle in and learn all of the tanks hiding spots before the puffer moves in.
Right now I'm just trying to get the tank set up the best way possible.

 

[thedood]

Ive used silica sand in tanks and ph was never an issue but we have rock hard water from the tap. It is possible I guess since sand comes from the ground that there is some of base substance like calcium that was inadvertently mixed in. Was this some sort of concrete sand or something?

 

[nchmi28]

Ive used silica sand in tanks and ph was never an issue but we have rock hard water from the tap. It is possible I guess since sand comes from the ground that there is some of base substance like calcium that was inadvertently mixed in. Was this some sort of concrete sand or something?

It's called "Handy Sand" It says Multi purpose crushed silica sand.

 

[thedood]

I looked at the analysis sheet on that sand it is 99%+ of silicon dioxide. No measurable carbonates to speak of. I dont think thats the source of your ph rise. Have you left plain tap water sit for a day or two and tested it?

 

[nchmi28]

Have you left plain tap water sit for a day or two and tested it?

Now that you mention it, I've never done that. I don't know why I didn't think to, Now that you say it, it is such an obvious first step in figuring this out.:redface: I put some water in a glass bowl, I'll test it in the morning.

 

[thedood]

They put all kinds of anti-corrosives (think Flint Mi.) and other chemicals into the water and who knows how the water reacts when those chemicals break down.

 

[nchmi28]

I tested the water from the fridge filter overnight and the pH was 8.2, GH slightly lower than 300ppm. So it was the water.

 

[WaterLife]

Yeah, it's not the silica sand (I use that myself) unless it contains additional minerals or contaminants.

Could be the rocks.

When filters are spent/exhausted/used up, they lose their filtering abilities, so it makes sense that minerals/ions would then no longer be filtered out (hence needing filter replacement).

Happen to know you KH/buffering capacity?

EDIT: Just read some more of the thread. Disregard

 

[thedood]

@nchmi28 Thanks for posting this question and providing your results. ASAP I will be building a water aging system. I was listening to a radio show that was talking about water systems in regard to whats happening to those folks in Flint and what types of chemicals are used and how they interact. You pretty much confirmed with your post a lot of what they said. I think I will do the same experiment with my own tap water.

 

[WaterLife]

@thedood sorry wasn't following along. I haven't heard about Flint, MI either. But what experiment will you be trying and what chemical reactions are you referring to?

 

[thedood]

Flint Mi was buying water from Detroit. In an effort to save money they started processing water taken from the polluted river, I believe the Flint river but I dont remember for sure. Anyway they stopped using anti-corrosives and the pollutants in the water corroded the lead pipes making polluted water pretty much poison not even safe to shower in. It is a huge problem for those folks. Anyway they were talking about the anti-corrosives and other protectants they use and how they react with the water, pipes, etc. It makes sense any chemicals added to the water are going to change the water chemistry ie ph etc. Those chemicals breakdown and voila you have a ph change.

I am just going to do the same thing as the op. I am going to let water sit and test it daily for ph, gh, and kh changes.