# [Wet Thumb Forum]-Dropping a bomb on KH test kit



## scalare (Feb 18, 2003)

Okay, now I may be just overly confusing myself with the jargon.. This Test Kit for carbonate hardness, does it actually test for the KH or is it actually testing for the alkalinity of the water sample? I am a little thrown off by this. I am using water from an R.O. unit that has been recently tested by an Aqua System's employee. I watched and he found the KH to be 0...precisely what is it supposed to be after running through a R.O. unit. I pulled out this kit (I know it is a cheapy) and it read 11 deg.dKH or roughly 197 ppm... he looked at the pamplet and was discussing with me why this test turned out this way and he told me that to him it seemed as though the kit was not truly testing for KH, but rather, the alkalinity of the water. Can anyone give me sound definitions of each for I thought previously that they were roughly the same. All imput greatly appreciated. P.S. - he said the unit was operating perfectly. HELP


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## scalare (Feb 18, 2003)

Okay, now I may be just overly confusing myself with the jargon.. This Test Kit for carbonate hardness, does it actually test for the KH or is it actually testing for the alkalinity of the water sample? I am a little thrown off by this. I am using water from an R.O. unit that has been recently tested by an Aqua System's employee. I watched and he found the KH to be 0...precisely what is it supposed to be after running through a R.O. unit. I pulled out this kit (I know it is a cheapy) and it read 11 deg.dKH or roughly 197 ppm... he looked at the pamplet and was discussing with me why this test turned out this way and he told me that to him it seemed as though the kit was not truly testing for KH, but rather, the alkalinity of the water. Can anyone give me sound definitions of each for I thought previously that they were roughly the same. All imput greatly appreciated. P.S. - he said the unit was operating perfectly. HELP


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## Rex Grigg (Jan 22, 2004)

The bigger question is why are using RO water?

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## Roger Miller (Jun 19, 2004)

All KH and/or alkalinity and/or carbonte hardness test kits measure alkalinity. Period. It's that simple. Don't let anyone confuse you.

Of course, that doesn't mean they all work right. If you are reading 11 dKH and he is reading nothing then clearly one test or the other is incorrect.

As an aside, there's no way to measure a concentration of 0 anything. The only things you can say is "at or below detection limit."

Roger Miller


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## farm41 (Feb 1, 2003)

I use RO too, for breeding apisto's and Rams. Not in my planted tanks though. They just get tap. RO in a planted tank is counter productive.

Matt
If you're not making any mistakes, you're not doing anything


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## imported_aspen (Feb 20, 2003)

mixing water to get the 'right' parms seems to me, to be dependant on what parms are coming from your tapwater. cutting tapwater with parms of gh 25 kh 18 ph 8.4 f/i, with r/o does not seem to be counter productive. i guess the question is, what are the ideal parms for a planted tank. i think that it would depend on what species you are keeping. i mix my tap (gh 8, kh 4, ph 7.8) 50/50 with r/o. all of the fish are softwater species.

if all test kits measure alkilinity, then why is the alkalinity tested with one kit, so different from another? fwiw, i use the AP kit to measure my kh.

nice to see you here, matt.

rick


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## scalare (Feb 18, 2003)

I am not using RO exclusively, the water here out of the tap (well water) is 9.6 Ph, off the charts on the KH and GH, phosphates off the chart. SO I mix a little with RO to help me out. Still having a hard time keeping apistos, rams, checkerboard cichlids (not the barbs), and of all things, discus.







. any suggestions?


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## imported_aspen (Feb 20, 2003)

water that is gh8, kh 4, ph 7.8, (my water) if changed regularly, will cause discus to eat and grow like crazy. i am following others' advice and cutting this 50/50 for my apistos. everything is going pretty good these days.

mind you, there is a lot more to keeping all of those species you mentioned, than just getting the water parms right. but that probably isn't a bad start.

rick


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## wetmanNY (Feb 1, 2003)

> quote:
> 
> Originally posted by scalare:
> ... the water here out of the tap (well water) is 9.6 Ph, off the charts on the KH and GH, phosphates off the chart. SO I mix a little with RO to help me out.


Phosphates off the chart? Doesn't the PO4 get measured as if it were carbonate in alkalinity tests? Could this PO4 be the "hidden" KH?


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## Rex Grigg (Jan 22, 2004)

I think you are confusing buffering ability there wetmanNY. Besides RO should remove the PO4 also. I would not mind having water that was gH 8, kH 4, and pH of 7.8. That's darn good plant water. Just use CO2 to lower the pH to around 6.8-7.0 and you would be off to the races. My water here is 7.0 gH and kH less than one.

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## CoralSea (Feb 7, 2003)

> quote:
> 
> Originally posted by wetmanNYhosphates off the chart? Doesn't the PO4 get measured as if it were carbonate in alkalinity tests? Could this PO4 be the "hidden" KH?


I believe both the phosphate and silicate test are skewed when the KH is 20+. I also remember reading that phosphate/silicate test are are effected by the present of the other. (i.e., the phosphate test may be off by the presence of silicate). Problem is I can't find the article, so take it with a grain of salt.


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