Water Hardness - and pH/CO2 struggle

[Batt4Christ]

My new GH & KH test kit came in today... and boy were my eyes opened!

TAP WATER:
GH = 1 degree
KH = 1 degree (17.9 ppm or less)

29g TANK:
GH = 6 degrees (107.4ppm)
KH = 5 degrees (89.5ppm)

55g TANK:
GH = 21 degrees (off the chart included in the kit) - I tested 2X to be sure!
KH = 6 degrees

So... I think I now understand why I can't get my pH down as much as I believe it should running pressurized CO2. It also explains why, over the space of a week, pH creeps back up, despite constant CO2 injection. Soon after a water change, pH comes down a bit easier. But after a week, it starts the creep back up.

So - time to investigate the rocks in my tank. My substrate is pfs, so I'm pretty confident in that. BUT I have a large pile of rocks in one end of the tank of collected rocks. I really would prefer not to have to take them out... But... add to it - what minerals are raising the GH so much?

Let the investigation begin...

 

[fish tips shaun]

I think

I think you should test the water your putting into the tank see what reading that gives u it could be the water u put in that the gh is high other then that did u boil the rocks befor u put them in that could be a part of the reason we talking about a fresh water if salt water sorry to wast your time I only know fresh water

 

[mfdrookie516]

Are you not using a drop checker? That would have no effect on its measurement. Sounds like doing a kh/ph comparison is out of the question though.

 

[Batt4Christ]

OK - to address the first question about the water I'm putting in the tanks:

My starting post indicated my tap water's hardness results - both GH and KH took one drop to see the color change - which according to the instructions = 1 degree of hardness. Since the test is no no more precise, we just know that my tap water has something less than 17.9ppm. I guess one might could use a larger test tube and use 10cc instead of the 5 normally called for - would that make the test exactly 2X more "specific"?

2nd Question - Yes - I boiled my rocks for several hours before they every got near my tank (also boiled my big chunk of wood).

I do have a drop checker. it is somewhat blue-green even without CO2 going.

I think the only real question is - what in my tank (especially the 55g) is adding minerals to the water? The rocks are locally collected. I guess I'm going to have to consult my cousin who is a geologist and see if he can identify the rocks - that ID might be enough to fully explain the significant rise in hardness.

 

[Batt4Christ]

Here is a pic of my drop checker as soon as I put it in my tank after changing the water in it (4dKH solution).

 

[ejaramillo01]

OK - to address the first question about the water I'm putting in the tanks:

My starting post indicated my tap water's hardness results - both GH and KH took one drop to see the color change - which according to the instructions = 1 degree of hardness. Since the test is no no more precise, we just know that my tap water has something less than 17.9ppm. I guess one might could use a larger test tube and use 10cc instead of the 5 normally called for - would that make the test exactly 2X more "specific"?

2nd Question - Yes - I boiled my rocks for several hours before they every got near my tank (also boiled my big chunk of wood).

I do have a drop checker. it is somewhat blue-green even without CO2 going.

I think the only real question is - what in my tank (especially the 55g) is adding minerals to the water? The rocks are locally collected. I guess I'm going to have to consult my cousin who is a geologist and see if he can identify the rocks - that ID might be enough to fully explain the significant rise in hardness.

I agree, the only possible source of the increase in the water hardness will be the rocks. Assuming that the substrate (pool filter sand) is ok....

 

[Batt4Christ]

A better angle, maybe:






And the rocks:

 

[Batt4Christ]

I agree, the only possible source of the increase in the water hardness will be the rocks. Assuming that the substrate (pool filter sand) is ok....

Yep. The area the rocks were collected from has a wide assortment of types. It came from a river bed (South Fork, Little Red River, Arkansas). The river has several varieties of sandstone, some limestone (which I am careful to not collect for aquarium use!) There is also some quartz and various other minerals in the area (as well as a rather extensive shale formation). Another stone common is Noviculite. The rocks in my tank, though eroded into these unusual round disks, I thought was Noviculite...

 

[Batt4Christ]

Oh - and as an addendum - I had heard many years ago (and see from a Google search that it is still fairly commonly said) that you can put a few drops of vinegar on a stone and let it sit - if no "fizz" or other reaction, it supposedly is "safe" (from a mineral point of view - bacteria, viruses, and parasites are another question all together).

None of my rocks had any sort of reaction back when they went in the tank.

 

[smileyface9]

What kind of fish is hidden underneath your rock? I really like it.

 

[Batt4Christ]

What kind of fish is hidden underneath your rock? I really like it.

View attachment 97029

Rhino, our albino bristlenose plecostomous.

 

[mfdrookie516]

Sorry if I'm not addressing the 'real' question (the kh weirdness)... just not real sure what to say about that part since I am far from a chemist.

As far as your drop checker though, that I know a tiny bit of info on. Are you using 4dkh solution and bromethyl blue (or standard pH reagent)? Just making sure you aren't using any ready made stuff out of a bottle since that stuff is usually junk.

 

[Batt4Christ]

Sorry if I'm not addressing the 'real' question (the kh weirdness)... just not real sure what to say about that part since I am far from a chemist.

As far as your drop checker though, that I know a tiny bit of info on. Are you using 4dkh solution and bromethyl blue (or standard pH reagent)? Just making sure you aren't using any ready made stuff out of a bottle since that stuff is usually junk.

4dKH made and according to directions I found (and double-checked).

API pH reagent

 

[aqua_chem]

Where did you buy your pfs?

Here's something to try. Put a smaller rock in a jar and add water to it. If you have another jar, add boiling water to it. Let it sit for a week and test it. If the KH goes up, then we have a winner.

 

[Batt4Christ]

Where did you buy your pfs?

Here's something to try. Put a smaller rock in a jar and add water to it. If you have another jar, add boiling water to it. Let it sit for a week and test it. If the KH goes up, then we have a winner.

pfs purchased at Lowes- Quikrete brand. Don't believe that is the issue. Both tanks have the same pfs from same lot. 29g tank, though seeing a rise in hardness, it was nowhere near the insane increase in the 54g. What's the difference? The rocks I have put in. My next step planned is to pull one and put in a non-reactive container with water of a measured pH and test over time.

 

[aqua_chem]

Are there rocks in your 29 as well?

 

[Batt4Christ]

Are there rocks in your 29 as well?

Yes, but not the same rocks, nor as many

 

[rkilling1]

4dKH made and according to directions I found (and double-checked).

API pH reagent

Your drop checker should not be green until it is in a tank that has CO2 around 30ppm. If the solution is really 4 dKH, then it is impossible for it to be green other then being in the tank for several hours.

My point, you should purchase a calibrated 4 dKH solution for your drop checker. It only costs a couple of bucks and can be found on several websites along with ebay.

 

[blert]

Test your 4dKH solution with your KH test kit.

 

[aqua_chem]

Did you use tap/drinking or distilled water to make the 4 dkh?