# I think my kh is rising due to my gravel how can I check it?



## chris1004 (28 Jan 2009)

I have a constantly rising kh, about 3 degrees a week now I have started EI dosing, previously I was doing 2x20% water changes a week and it wasn't so noticable. I check my ph and kh regularly as a means to check the dissolved co2 in my tank which is how I came to notice it. I have no rocks in my tank only bogwood and plants and a textured jewel background (which I regret buying as the paint has almost completly flaked off in under 6 months, what a waste of Â£65). I am pretty sure that the gravel must be causing this but how can I check it cheaply? The guy at my LFS tried to sell me 'ph down' to check it!!There must be a cheaper way surely...I think I found a piece of crushed shell in there the other day as it snapped between my fingertips under pressure, the sub substrate is jbl aquabasis plus this couldn't be causing it surely? 


Although it doesn't appear to be a major problem I think it would be more benificial to try to keep stable water parameters where possible. Any and all comments would be gratefully appreciated.


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## Ed Seeley (28 Jan 2009)

pH down won't check your substrate at all.  It is a buffer to reduce the pH.  What you want to use is a strong acid.  I have used brick cleaner (hydrochloric acid) in the past and it does a good job.

You don't say how much the KH and pH are rising but if you're doing large weekly water changes and it's only rising slowly then I really wouldn't worry about it.  You'll do far more harm chasing a set level of either pH or KH than a slowly rising value of either will.


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## ceg4048 (29 Jan 2009)

chris1004 said:
			
		

> ...Although it doesn't appear to be a major problem I think it would be more benificial to try to keep stable water parameters where possible.


I'm in complete disagreement. What's infinitely more important is stable CO2, stable nutrient dosing and stable water changes. As Ed says, anything else is unimportant.

Cheers,


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## chris1004 (29 Jan 2009)

ceg4048 said:
			
		

> chris1004 said:
> 
> 
> 
> ...



Hi Clive, 

all the other elements are stable and I never implied that they weren't,I am now using full EI (50% water change, ferts and 30ppm co2) thanks in no small part to your previous advise and your article in the tutorial section. However I am keeping fish that according to popular literature prefer soft acidic water, which broadly speaking I have but I would like it a little more stable if thats possible or at least I would like to be confident that if I were to go away for a couple of weeks I wouldn't return to a tank load of dead fish due to lake Malawi conditions (ok a bit extreme but you get my drift).


I actually asked "how can I check my substrate cheaply?" or words to that effect. If I do find that it is the substrate causing my KH to rise then I will be faced with a simple decision as to what if anything I will do about it. If it is simply a case of a tank strip down and replenish the substrate with somthing more suitable when the time comes then so be it. I have never been afraid of a little hard work, in fact its a labour of love and I am fully aware that it is not an acute problem that needs immediate remedial work.


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## chris1004 (29 Jan 2009)

Ed Seeley said:
			
		

> You don't say how much the KH and pH are rising but if you're doing large weekly water changes and it's only rising slowly then I really wouldn't worry about it.  You'll do far more harm chasing a set level of either pH or KH than a slowly rising value of either will.



Hi Ed,

First line of my post mate, "kh rising 3 degrees per week". Ph is pretty stable though (between 6.6 and 6.8 ) and I am not worried about it at all anyway after our previous communications with regard to water quality, PH and KH. The only reason I am testing the PH and KH is to check the CO2 which is as stable as can be expected at between 30 and 35ppm, assuming of course that my test results are somewhere near close. I would just feel a lot better if the KH remained stable. I am prepaired to strip the tank down completly and replace the substrate and start again if I think it necessary, but may wait until the sub-substrate neads replacing in a year or so to do this as it makes more sense on more than one front.


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## Ed Seeley (29 Jan 2009)

Right I meant what is it starting at/going to as if it's really low then things dissolve easily to up the KH whereas if it's high then it changes.  However if your pH is below 7 it must be fairly low.  With large weekly water changes that kind of increase really won't be a problem and as the gravel matures the amount of calcerous material will be depleted and the rise will be much less.

Measuring KH and pH to work out CO2 levels isn't the best way as there are other factors apart from CO2 that alter the pH of the water so those tables aren't accurate in a fish tank situation.  This is why we use drop checkers with pure water adjusted to 4dKH so that nothing apart from the CO2 levels is changing the pH of the drop checker and its indicator colour.  Then any changes in the KH of your tank water will be irrelevant anyway!


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## ceg4048 (29 Jan 2009)

Exactly as Ed says. You will always calculate a higher CO2 content than is real if you use the parameters in the tank as the basis of your calculation. The real parameter you'd need to worry about for your soft water fish would be Total Dissolved Solids (TDS) because it's the conductivity of the water and the particle count that will have an effect. If it is suspected the substrate is releasing dissolved solids it can be tested cheaply by taking a sample and using a strong acid such as Hydrochloric or Nitric to test it's reaction. If the substrate grains fizzle then you know it's releasing solids...

Cheers,


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## chris1004 (30 Jan 2009)

Ed, 
the KH is starting at 4 and rising to 7 or at least it was, the PH values quoted in my last post are at the end of the co2 injection cycle. I have stopped putting in so much reminaralising agent since we spoke on the water chemestry topic with regard to the KH. I do like the info about things maybe improving with time though.

Clive,
the TDS of my tank water is 231ppm measured with a TDS meter. As I've said before I use 100% RO water all of the time for my water changes which has a TDS of less than 1ppm. A lot of the TDS that I now have is probably due to a combination of disolved reminaralising agent, ferts and waste by products I guess. Although to be absolutly honest I don't really know very much about TDS in relation to my fishtank as I only normally use my TDS meter to check the quality of my RO water so that I know when to change the DI resin in the filter.

Interestingly the barr report suggests using KH/PH measurements as a way (and I believe Tom Barrs prefered method) to determine the co2 value and I am sure that I have read elsewhere on this site that drop checkers aren't all that reliable, but without trawling back through all that I've read on this site I'm only relying on my ageing memory,which is dangerous in itself, LOL. I try to keep clutter out of my tank where possible and it is only for this simple reason that I do not use a drop checker, although after the above comments I am considering changing my mind and using one.


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## beeky (30 Jan 2009)

Drop checkers aren't fool proof and are slow to change. The colour you see is actually what the CO2 level was a couple of hours prior, so they're not fantastic but are better than using tables of pH/KH. Many acids other than carbonic exists in most fish tanks which can skew the results. This was the way people used to measure CO2 before drop checkers came about, but now most people use drop checkers. There's nothing intrinsically wrong with tables, just be aware of the limitations and don't take them as gospel.

Regarding the gravel, I understand why you want to resolve it. IME most gravels alter water chemistry. To check it, use some kettle descaler (something like KillRock) and see if it fizzes. It's generally more commonly available than pure acids.


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## chris1004 (30 Jan 2009)

With regard to TDS I have started another post under the 'water chemistry' catagory as I anticipate that a discussion/tutorial on TDS could be very interesting, it certainly would be for me. 


Oh go on Clive please spill the beans I'm practically begging you...


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## ceg4048 (1 Feb 2009)

chris1004 said:
			
		

> Ed,
> the KH is starting at 4 and rising to 7 or at least it was, the PH values quoted in my last post are at the end of the co2 injection cycle. I have stopped putting in so much reminaralising agent since we spoke on the water chemestry topic with regard to the KH. I do like the info about things maybe improving with time though.
> 
> Clive,
> ...



I can guarantee you 100% that Barr does not advocate using tank water KH/pH to calculate CO2 content. In fact it was his realization that organic and inorganic acids in the tank affect the pH of the tank water and which corrupts this calculation that later contributed to the widespread use of the dropchecker. The KH/pH/CO2 relationship in water is voided when acids other than Carbonic acid is present in that water sample. The checker is not accurate however, using tank water KH/pH is even less accurate. What he implied was that if one doesn't want to spend $1000 for an accurate CO2 meter then a dropchecker is about as good as one can do. Since he does have a CO2 meter he does not use a dropchecker.

See CO2 MEASUREMENT USING A DROP CHECKER

Cheers,


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## chris1004 (1 Feb 2009)

Thanks for that link Clive I have read it with interest and will be investing in a drop checker in the near future. 

I do feel a bit silly now after my comments on the post that you quoted but then again as I said I was relying on my memory which I for one should have known is a dodgy thing to do.Seriously though I have been on this site at nearly every opportunity since joining and I have read so much info that some of it seems to have gotten confused, sorry.


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## ceg4048 (2 Feb 2009)

No worries mate.  It's easy to get information overload while cruising the information super highway. As you gain more experience, many things which at first seemed confusing or counterintuitive will become second nature.  

Cheers,


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