# low KH



## nickyc (27 Apr 2008)

It's been a long long time since I took out my dusty test kits, but for one reason and another, I tested KH and GH today.  While the GH is around 8-9, the KH is 0!     pH is 6.5.  Before I started using CO2 (currently just the Nutrafin kits) both KH and GH were quite high, and pH hovered around the 7.2-7.5 mark.  Low KH has never been a problem I've had to deal with.  :?   What do I do?!  All advice gratefully received as ever!


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## Ed Seeley (27 Apr 2008)

Leave it.

I run all my tanks at home with pure RO and all have 0dKH.  The fish are fine.

You can use Sodium bicarbonate to raise the KH but you really don't need to unless you have fish that need alkaline water.  Or, with our tap water, just up the water changes and your KH will soon be back up!!!


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## nickyc (27 Apr 2008)

Thanks Ed. Was quite worried so that's really reassuring.  The tank has got cories, botia, a plec, some rainbows, a load of White Cloud Mountain Minnows and a few assorted refugees - none specifically liking hard water as far as I know?!  But then as you say, with our water, it's not something I've ever worried about!!  If anything it's been quite the reverse and I used to pinch my b/f's RO just to bring the hardness down from time to time.  I haven't used any for ages though so I'm quite puzzled!


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## Ed Seeley (27 Apr 2008)

I'm not trying to be critical in any way here but have you been keeping on top of the water changes or added anything new to the tank like wood recently?  KH will drop over time as the results of denitrification in the filter produce organic acids that will use it up.  This is supposedly the cause of the infamous 'pH crash' which is really a result or poor maintenance as far as I can see.

Whatever the cause a good clean of the tank and filter and upping the water changes will soon sort the problem.


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## nickyc (27 Apr 2008)

No new wood, but I did do my back in a while back so water changes have been minimal for a while.  The last few weeks have been back to normal - I do about 20%.  I guess it will return to normal after a couple more.  Thanks for putting my mind at rest!


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## nickyc (28 Apr 2008)

And it turns out that my b/f (who kindly took the strain while my back was out) filled up with pure RO!  Am slightly concerned as I usually remineralise with Nottingham tap, but what's done is done and I'm not ungrateful!  I take it a few pure tap changes will put back whatever was missing??


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## Ed Seeley (28 Apr 2008)

nickyc said:
			
		

> And it turns out that my b/f (who kindly took the strain while my back was out) filled up with pure RO!  Am slightly concerned as I usually remineralise with Nottingham tap, but what's done is done and I'm not ungrateful!  I take it a few pure tap changes will put back whatever was missing??



As long as you know what did it I wouldn't worry at all.  Your GH is still higher than I run mine after remineralising!!!!  The only thing you may be short of will be magnesium but I think you'll be fine.  Once you do your next water change things will start to return to normal.


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