KH is 21

[KatieJ]

I just got done doing a water test, and my KH came out as 21 - I was using the API test kit. It literally took that many drops for the color to change and I've been getting similar results over the last couple of months, regardless of the pH/CO2/etc. With the GH, it took like, a drop before the water started turning green.

Everything else reads out as good - ammo's 0, trites are 0 and trates are below 5. The pH is at around 7.5ish and I just got done with a water change. I'm thinking there's definitely something in the university's water; I heard they've had problems with hard water a lot. Copper levels are about 450 ppb here; could that be the cause?

I suppose I could do a half-and-half of RO/DI water if you guys think it's needed, but it would be difficult (and irritating) to trudge gallons of water home on my bike each week from the lfs. I have had a couple of shrimp deaths here and there, but I don't know if that was from the KH or something else.

So, what should I do about it? Or should I leave it be since I've gotten these results before? (KH was 20 drops last time I checked, and GH was almost 0)

 

[Terrance]

Have you seen your nitrate level above 5ppm in the past few weeks?

Yes copper does lead to those mysterious shrimp deaths.

 

[KatieJ]

No, no nitrate spikes. I'm going to take a sample of water to the lfs this weekend to be sure I just don't have a faulty test kit or something.

 

[Terrance]

If you've never seen your nitrate above 5ppm or its undetectable, then it could be that all your bacteria died from the low buffer. Just add some crushed coral to your filter to increase the kH. Do you have plants in the tank?

 

[aqua_chem]

Just to confirm, this is 21 dKH and not 21 ppm, right? And you also know that you have to shake the nitrate test kit thoroughly before using it?

You might also try testing water directly from the tap to see if you have something leeching in your tank.

 

[KatieJ]

I'm not sure what it converts to - all I know is that it took 21 drops for the solution to turn yellow.

And yeah, I'll try that.

 

[blert]

I'm not sure what it converts to - all I know is that it took 21 drops for the solution to turn yellow.

And yeah, I'll try that.

What brand test are you using?
Are you using 5 or 10 ml of water when you test?

 

[KatieJ]

API; 5 ml.

 

[blert]

I'm not an expert here but I'd say 60% RO/DI, 40% tap and mix in 'RO Right' to bring the GH up a tad. That should bring the KH down to about 8? Other than that I'll bow out to Aqua_Chem, he's good at this stuff.

Just a thought, do you have access to a well?

 

[aqua_chem]

I would implicate the copper in the water before the hardness in the shrimp deaths. Are you seeing any other problems caused by the hard water?

 

[blert]

I would implicate the copper in the water before the hardness in the shrimp deaths. Are you seeing any other problems caused by the hard water?

But isn't a good water conditioner supposed to neutralize (or bind to) copper and allow it to precipitate out?

 

[aqua_chem]

It should, but if you occasionally have more of it than normal or you don't have enough conditioner, you might occasionally see an issue. 500 ppb seems awfully high to me. I wouldn't be particularly worried about either if you're not seeing issues.