# Kh / Gh understanding



## nqsc (Jan 4, 2019)

Hey guys. So, I'm currently fishless cycling a 75g peacock tank (I'm new to this). I'm about a week in, but I just got an api kh/Gh test kit. At the tap, my kh is at 35.8 ppm & Gh is at 53.7ppm. pH is 7.4. At the tank currently, kh is at 89.5 & Gh is at 107.4. I just purchased some seachem lake salt as well as Malawi buffer. Also my ph at the tank is 8.0. I have holey rock and Carib sea cichlid substrate in the tank. With all that said, what do I need to do or add to the tank before adding fish and I'm assuming I should add these supplements during water changes?


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## DJRansome (Oct 29, 2005)

If your tank is 8.0 and stable without adding anything, I would not add a thing.


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## nqsc (Jan 4, 2019)

Ok, thanks. Based off my parameters though, when I do a water change, should I worry about adding anything to the new water before it goes in? Tia!


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## zimmy (Aug 13, 2010)

If you're doing large water changes you could add some of the products you've purchased. BTW a much more cost effective approach is to use baking soda and epsom salt. They'll cost a fraction of what you paid for those products and do the same thing.

The use of baking soda will keep your pH stable at around 8.2. Read this article from the library for details.


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## DJRansome (Oct 29, 2005)

One last thing to try before additives. Test the water from your tap after having it sit on the counter for 24 hours.


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## nqsc (Jan 4, 2019)

Will do, thank you!


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## nqsc (Jan 4, 2019)

DJRansome said:


> One last thing to try before additives. Test the water from your tap after having it sit on the counter for 24 hours.


So after 24hrs, my tap parameters are: pH-7.8, gh-53.7ppm, kh-71.6ppm or 4°kh. Thoughts?


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## DJRansome (Oct 29, 2005)

4 drops KH should work but it is marginal.

For that would try crushed coral in the filters and see if you can boost the KH without altering pH.

They might all go up a little, but that would be OK too.


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## nqsc (Jan 4, 2019)

DJRansome said:


> 4 drops KH should work but it is marginal.
> 
> For that would try crushed coral in the filters and see if you can boost the KH without altering pH.
> 
> They might all go up a little, but that would be OK too.


Ok, so just bag some coral and place in either filter? I have a hob and a cannister. Fyi, I just checked the tank kh and it's currently at 5°kh.


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## DJRansome (Oct 29, 2005)

But the tank has all the "stuff" in it. The idea here is to just do PWC with tap water and overtime your pH will be 7.8.

The only reason to bump the KH a little is to keep the pH stable at 7.8.

Yes, I would put crushed coral in one tray of the canister. Instead of whatever media you have now. Rinse it for like an hour (literally). It is VERY dusty and very hard to get clean.

Realize that when you remove one tray of existing media, you remove beneficial bacteria. I would bag the old media you are removing and float that in the tank for 2 weeks to ensure you don't have a mini cycle.


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## nqsc (Jan 4, 2019)

DJRansome said:


> But the tank has all the "stuff" in it. The idea here is to just do PWC with tap water and overtime your pH will be 7.8.
> 
> The only reason to bump the KH a little is to keep the pH stable at 7.8.
> 
> ...


Ok, I just ordered the coral. Last 2 questions, how much of this stuff do you think I should bag? Maybe 1 cup, or more? And how long does it last; will need to replace it at some point? Thanks for all the help!


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## DJRansome (Oct 29, 2005)

I would fill up one tray in your canister. I assume you have at least three trays...one sponges, one fine filter and one "other biomedia".

I would swap out the "other biomedia" and fill that tray with crushed coral. Mine has lasted almost 10 years.


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## nqsc (Jan 4, 2019)

Got it, thx


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## doosty (Feb 22, 2019)

To buffer pH while raising kH, I second what DJ said about using crushed coral in your filter (preferably in media bag because it will leech even if rinsed".

You might want to try a nice big piece of Texas Holey Rock in the tank too.

I have a 40lb Rock in my 55gal and it really cuts down on how much baking soda/epsom salt I need to add to balance kh and gh respectively. Fish love it for hiding and resting as well.

When carbonate hardness reaches 7-13 dkh, pH usually becomes most stable.

I am looking to keep my tanks at 7dgh and 7dkh.


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## nqsc (Jan 4, 2019)

doosty said:


> To buffer pH while raising kH, I second what DJ said about using crushed coral in your filter (preferably in media bag because it will leech even if rinsed".
> 
> You might want to try a nice big piece of Texas Holey Rock in the tank too.
> 
> ...


Thanks, I have about 40lbs of holey in there now. Everything seems to be doing well so far


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## Methodical2 (Feb 11, 2019)

Question. How long does it take for the crushed coral to start affecting the water? Does the crushed coral eventually have the same/similar biological affect for the tank?

Thanks...


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