Hardness readings don't make sense

[sinibotia]

I just tested the hardness of my water, and the results seem impossible- it's claiming both my tank and the tap have KH 3 degrees and GH 53.7 ppm. But all the tap water in the surrounding area is hard (or so I've been told by the nearest petsmart and my aquaculture professor a town over), and the water leaves hard water stains where it dries. I also ran a test on my shelldweller tank, which has aragonite sand to buffer the water. The KH of that tank is 6 degrees, but the GH is still allegedly 53.7 ppm.

Do these results make any sense? I think the test kit is fairly old; how would an expired test kit behave, though? I just find it really hard to believe these results.

 

[sinibotia]

And the pH of the tank is 7.6, which seems unlikely with low hardness.

 

[Delapool]

Could be possible. Tap ph here is around 8, kh is 4 to 6 and gh around 5 from memory. Varies a bit between winter and summer. Can you take a water sample into a lfs to get it checked?

 

[sinibotia]

Well, I used a very sensitive, high quality KH test kit at the aquactulture research center at my university to test the water there. Got a KH of 12 degrees. Brought home some water to test and got 4 degrees. Gonna have to say that that calls it- my KH test kit is borked. I'm taking a water sample from the tap here to the ARC tomorrow to test it using the better test kit.

 

[ScotJudd]

Hi. For the cost involved I would buy a new test kit. As for the evidence of hard water (scale deposits on evaporation) a high Gh would explain that. If your Kh is indeed above 10 then a Ph of 7.6 is quite likely. Over the last year I have settled on a Kh of 6 to give the best Ph balance. Hovers around 7 depending on the time of day as I use Co2 which drags it down a little. When the Kh was at 0-1 the Ph tended to crash.


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[sinibotia]

Hi. For the cost involved I would buy a new test kit. As for the evidence of hard water (scale deposits on evaporation) a high Gh would explain that. If your Kh is indeed above 10 then a Ph of 7.6 is quite likely. Over the last year I have settled on a Kh of 6 to give the best Ph balance. Hovers around 7 depending on the time of day as I use Co2 which drags it down a little. When the Kh was at 0-1 the Ph tended to crash.


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Yeah, the plan is to buy a new test kit. I would have checked GH as well, but shockingly enough I'm not sure there was one in the ARC... if there was, i couldn't find it.

Any recommendation on a hardness test? I was going to get API but I have a 20% off coupon on tetra test kits.

 

[Delapool]

Well, I used a very sensitive, high quality KH test kit at the aquactulture research center at my university to test the water there. Got a KH of 12 degrees. Brought home some water to test and got 4 degrees. Gonna have to say that that calls it- my KH test kit is borked. I'm taking a water sample from the tap here to the ARC tomorrow to test it using the better test kit.

Yikes, always thought kh would be a simple test. Which home test kit was that out of interest?

 

[ScotJudd]

I can't comment on other brands but I use the API liquid test kit for all my water testing. The hardness test kit contains both Kh and Gh test bottles and is not expensive. Personally I would save the 20% voucher for another purchase and get the API off the Internet.
Does anyone really still pay the inflated prices at fish shops for their branded goods? Even with postage I save loads using the Net.


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[Delapool]

I use API test kit as well.

 

[sinibotia]

API was what I was using but allegedly my test kit expired in 2009 or so. Never bothered using it ever because I could tell just by water pH behavior what my home KH was and I never kept anything that cared much about high hardness (mostly SA stuff that enjoyed my 6.0 pH and aparently low hardness out of the tap).It hadn't even been opened until I used it last week.

Tomorrow, I'm going to bring in my own test kit and see if I have time for the penultimate test- side by side comparisons of tests the EXACT same water (out of the exact same hose in the exact same building). Also going to adjust my methodology with the more precise test kit as I can think of where I could have made mistakes.

 

[Delapool]

API was what I was using but allegedly my test kit expired in 2009 or so. Never bothered using it ever because I could tell just by water pH behavior what my home KH was and I never kept anything that cared much about high hardness (mostly SA stuff that enjoyed my 6.0 pH and aparently low hardness out of the tap).It hadn't even been opened until I used it last week.

Ah thanks for the post back. I have compared the liquid and strip API kh test and got a good comparison but never tested with another brand.

 

[sinibotia]

The brand I used for the "advanced test" was for reef tanks and measured to the .1 degree. I really don't understand how a sealed bottle of reagent "goes bad" but.... I'm not sure what else to say. I have a hard time believing anywhere around here has water as soft as 3 or 4 degrees.

 

[Delapool]

Odd, you would think a reef test would be the bees knees. Just too old do you think?

 

[sinibotia]

Odd, you would think a reef test would be the bees knees. Just too old do you think?

The reef test is the one I used at the aquaculture research center, I'm pretty sure it was accurate.

 

[sinibotia]

The saga continues: Picked up a new KH test kit and I'm getting the same readings as the "expired" test kit. Also found out that the water I thought was from the same source was a different source, so it would seem the local water really is 3 degrees KH. But I have no way of knowing the total hardness. How much does total hardness matter though, particularly for breeding ram cichlids? And is it likely that total hardness is significantly higher than KH? From what I've read theyre usually pretty similar.

On an slightly related note, is there anything useful I can determine with a calcium test kit in freshwater?

 

[sinibotia]

Shockingly enough, it seems the water here actually really is fairly soft. I picked up an electronic TDS meter for my discus project, and tested my South American tank fresh after a ~50% water change. Got around 110 ppm, which means the maximum possible GH is about 6 degrees- not all that hard after all. In fact, I could probably breed my rams in that without changing anything.

Now if only my male would get well enough to spawn....

 

[Delapool]

How does that work to convert tds to gh out of interest? I've looked at getting a tds meter and getting a better gh test (use strips) but never really worried as I'm mainly interested in kh.

 

[ScotJudd]

Hi. I use a TDS meter but it cannot tell you the Gh only the Total dissolved solids. Adding buffers increases TDS. Adding liquid ferts increases TDS.
What I check is how the TDS is reading compared to the TDS of the water added at water changes. If the TDS in the tank is in the range of 70-110 above the water added at water changes (my base level) then fine but if it creeps higher then I use that as an indication that dissolved solids are on the rise and I need to do a WC.
Having said that, this nearly always coincides with a rise in Nitrates, so a water change is needed anyway. The TDS meter just gives me an easy way of checking the water daily, rather than doing a daily nitrate test which is a bit over the top.
A TDS meter in my mind is a convenient way of tracking the water quality but not an essential tool.


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[Delapool]

I think you sold me when you said easy . I can never figure out the colours.

So TDS is just an indirect measure as the link has below? I assume then gh couldn't read higher than TDS?


http://www.theaquariumsolution.com/tds-what-does-it-mean-and-why-should-i-test

 

[ScotJudd]

No - TDS is the combination of Gh, Kh and other dissolved solids. So Gh can't be higher than TDS.


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