Insanely high GH and KH - The Planted Tank Forum
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post #1 of 5 (permalink) Old 04-17-2015, 06:12 PM Thread Starter
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Insanely high GH and KH

I did my first parameter check on my 2.5 month old 5 gallon tank today. I've been patiently waiting for my diatoms to disappear but have had no luck so wanted to know if I had something else going on. For now I only have test strips.
GH 120
KH 180
pH 7
NO2 ~.5
NO3 ~ 30
My first reaction is I had to have done something wrong, but this isn't my first time reading test strips by any means. Is it possible to have these readings? I have a large 'lava rock', eco complete, some small stone fragments that hold my plants down, around 5 plants, two ghost shrimp, a nerite, and a platy. Could the rocks be part of the problem? Could this be why the diatoms are thriving? I am beyond confused.
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post #2 of 5 (permalink) Old 04-17-2015, 07:35 PM
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hmmm, had the same on my 5 gallon tank, but I make my own water and was able to bring it down, and change the mix of minerals/salts I use.

My NO3 remains at about 30, seemingly no matter what i do, currently I read:
Ammonia 0, NO2 0, NO3 30, GH 100, KH 80, PH 7, Phosphate 5 PPM
Tank contains a betta, 4 cory's, and 3 snails, as well as live plants. The algae problem has been manageable, but I'd like to get the NO3 and Phosphate under control. Doing 35% water changes weekly.

Fish in seeming good health. Mr. Betta building one bubble nest after another.
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post #3 of 5 (permalink) Old 04-17-2015, 07:58 PM
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Assuming those GH and KH readings are in ppm, they're not insane..

in German degrees you have:

dGH 6.78
dKH 10.08

Neither of which is insane.. a bit on the hard side, yes.. insane, no.

If those numbers are in german degrees, well, I think you've exceeded the solubility limits for water and you should have calcium carbonate precipitating.

Check what units your test strips are reporting in...

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post #4 of 5 (permalink) Old 04-18-2015, 12:18 AM
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Test strips usually report ppm.

Test the tap water.

Take out a few of the stones holding the plants down and test them in their own jar of water. See if they are contributing to these readings.

Other than that, Platies are somewhat hard water fish. That GH is at the low end for them.

I find it odd that the pH is so low when the KH is so high. Usually I see neutral pH when the KH is about half of yours.
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post #5 of 5 (permalink) Old 04-18-2015, 01:08 AM
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I have a similar problem but have figured it out my kh was so high it took 36 drops to get my color change !
My gh was 174 ppm not bad
so I tested my tap water now that I have moved it took over 40 drops !!

After some looking around and testing some store bought water and deciding it was not my test kit

The answer seems pretty clear !

Use r/o water for you that would be inexpensive to simple buy some fow water changes !

for me I found a kit on amazon for 150 bux

Now I will have tasty clean tap water to drink and to dump in my tank !

Not sure how well that will work for you

I have read that surface agitation will help get those numbers down over time

Also boiling your water for ten minutes is supposed to drop kh by 80 ppm

Have not tried this as I am working on a 55 gal tank and my kh was closer to 700 from what I could find online

Good luck my friend !
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