# KH and GH question



## kkau1 (Jun 22, 2006)

Hi,

I have a 20 Gallon planted tank. I recently added a lot of plants and a DIY Co2 system, as well as some lava rock. Before this change my water parameters were:

Ph: 8.5
Kh: 6 dh
Gh: 9 dh

But now after a week with new plants and co2 my tank water is:

Ph: 6.5
Kh: 14
Gh: 19

I really don't know what's going on. I think i may have gotten a little too zealous with my Co2 ( 2 diffusers with 2 2L bottles each). But what could cause my Kh and Gh to double? Think it could be my testing kit? Or does the lava rock raise both Kh and Gh this dramatically.

Also, I've been using only RO water when i do weekly water changes and not my tap water, which is closer to the first set. The reason i used RO water was to help in bringing down the PH a little.

Any help would be really appreciated. 


Kkau1

Edit: I guess i should also say that there's about 2-3 weeks between the first set and second set of data. During this time i've only really been measuring PH, and the few times i measured KH during this time it was hanging around 9 ish. This setup has become a problem just these last few days. My Amano shrimps started to die off. I was able to save 2 though and moved them to a holding tank.


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## hoppycalif (Apr 7, 2005)

Try taking one of the rocks out and dripping some muriatic acid (swimming pool acid) on it. If it fizzes the rock contains carbonates, probably calcium carbonate which raises both KH and GH.


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## kkau1 (Jun 22, 2006)

dripped some Muriatic acid on a few of the rocks. Funny thing is out of 5, 1 fizzled a little. All these lava rocks came out of the same bag I got from a garden center though.


This poses a big problem. The tank that this is all happening in is only temporary while i gather a few last things for a bigger tank. In this new tank i made a background by silicon-ing a bunch of lava rocks together on the glass.

Will dissolving rocks pose a serious threat to a planted tank? Will this problem go away once the carbonates are done dissolving?


Thanks~


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## Laith (Sep 4, 2004)

Yes, it does sound like the lava rock could be affecting your water parameters. And the addition of CO2 will increase the "leaching" rate of the rock due to the carbonic acid that is created. However that's a pretty big jump in Kh and GH for a couple of weeks, especially as you've been adding RO water which should have a KH and GH of 0.

This may be a stupid question but I've seen it happen... are you sure you're not collecting your RO water from the wrong, "reject" water output of your RO unit? This would be water high in KH and GH...

Your tap water pH is probably closer to around 7.8 or so (given that the KH is 6). Let your tap water stand in a glass or something for 24 hours before measuring the pH. From what I can see, there is nothing wrong with just using your tap water for water changes. The addition of CO2 will bring the pH down anyway and in any case don't worry too much about pH levels; they're not as important as one would think...

If you do want to continue to use RO water for your water changes (once this is sorted out), you normally need to add back in some of the minerals the RO unit takes out. Pure RO water is not good for your fish life or your plants. One product that is commonly used for this purpose is Seachem's Equilibrium (along with some baking soda to raise the KH) or you can get Greg Watson's GH Booster (www.gregwatson.com).

But in your case something is influencing the KH and GH in the tank anyway...

And IF your KH and pH readings are correct, you may have too much CO2 going into the tank. I ask because Amano shrimp shouldn't have a problem in a KH of 14 and a GH of 19 (I have them in a KH of 15 and GH of 18 ). Are there any other fish in there and if so, are they "gasping" at the surface (usually a sign of too high CO2)?


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## kkau1 (Jun 22, 2006)

Thanks for the replies~

I tested the RO water i have and KH and GH are basically 0. I do believe that my problems with the amano's are from injecting too much co2. This is frustrating though, i thought Lava rock would be safe.

Don't see my fish gasping at the surface, however they've been acting very strange as of late. I have a few Neon tetras and two SAE's. Usually the tetras would be schooling and the SAE's would be doing their thing, but before my Amano's started to die off the tetras seemed to scatter and hide on their own, and the SAE's seemed like they were hiding too. Very strange. Also, the tetras seem to be fighting a lot more between themselves. 


My question is, will this leaching be very harmful for a planted tank? And will it go away after it's done leaching? Or will GH and KH just keep skyrocketing?


Thanks~


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## Bert H (Mar 2, 2004)

What is your substrate, and how old is it? Some substrates like Eco, and Onyx, will cause temporary kh/gh spikes. If you're using RO water, you must be adding back some Ca and Mg, any chance you've over done that?


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## kkau1 (Jun 22, 2006)

My susbtrate is Eco Complete, it's probably about a little over a year old by now. I havne't been adding anything back into the RO water thus far, just ordered the Seachem Equilibrium so next water change will hopefully be using that. 

So are you saying that RO water and Eco will raise KH/GH? 


Thanks~


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## Bert H (Mar 2, 2004)

> So are you saying that RO water and Eco will raise KH/GH?


No. My point was in case it was a new batch of Eco, it could explain the increase in gh/kh.


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## kkau1 (Jun 22, 2006)

Ah gotcha.

I guess my final question is this: How will a high/climbing KH/GH affect a planted aquarium?


Thanks for all the responses and help so far~

Kkau1


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