# raising kh/gh



## fishman8888 (Mar 22, 2014)

Hi...i'm looking for the most natural and most stable way to raise kh and gh in my tank...

I've read you can put crushed corals in your tank/filter ..

Then alkaline buffers/equilibrium ...

Or calcium carbonate/magnesium sulphate/baking soda....

I have a 125 gallon tank...with a kh/gh of 0... i want to get my kh up to around 5 or 6.. asap

My tank has been in operation for 10 months
Ammonia: 0
Nitrate: 5ppm
Nitrite 0
Ph: 6.5-7ish (borderline on liquid test chart)
Gh: <20
Kh:0

Any advice is much appreciated, thanks everyone


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## fishman8888 (Mar 22, 2014)

Also....maybe opinions for optimal kh/gh based on stock would be a good idea

1 black angel
4 ctenopoma leopards
5 blue three spot gouramis
9 bosemani rainbows
1 driftwood catfish

What would be a good kh to aim for?
Is there any need to rehome?

Additional info: ctenos & angel have been with me since the beginning


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## Rockman (May 19, 2013)

It's all very doable.

Crushed coral is probably the cheapest, simpliest and "most natural"; but it's also the least controllable. I'm using crushed dolomite (a mix of calcium and magnesium carbonate. It's slightly less soluble than CC; so the final pH/GH/KH is lower) in my big tank right now; which has been working pretty well for the last few years. It's not the best method if you plan on doing lots of large water changes though; as you'd end up with constantly changing water chemistry.

Lots of people use pre-mixed commercial products. They work pretty well and there are instructions right on the box; so it's still fairly easy. You'd dose everytime you did a water change; so you wouldn't have to worry about shocking the fish. The downside is they're fairly expensive, and some of them use compounds that you might not necessarily like if you're the nitpicky sort (they use a lot of sodium and chloride salts; which are cheap and easily dissolved. But sodium and chloride are kind of junk ions; they don't do much besides drive up the TDS). 

The DIY option is the most difficult for the chemistry-disinclined; but also the most flexible (you can dose exactly what you think you need). The bulk chemicals are pretty cheap; which is nice in a larger tank. I tend to prefer this method for most of my tanks. I use a mix of calcium chloride (I use the stuff they sell for pools at the hardware store), magnesium sulphate (epsom salt), potassium bicarbonate, and sulphuric acid. I've done up a spreadsheet that lets me tailor my water to whatever I want (figures out how much stuff to add to get a given GH, KH, pH and TDS).


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## Rockman (May 19, 2013)

fishman8888 said:


> Also....maybe opinions for optimal kh/gh based on stock would be a good idea
> 
> 1 black angel
> 4 ctenopoma leopards
> ...


Well... the rainbows would like harder water (probably starting from GH 10, KH 5 or so) whereas all the others are more softwater fish (although I don't know about the driftwood catfish... there are lots of different 'driftwood catfishes' that come from different parts of the world). There is probably a happy medium in there though (the softwater guys are all fairly adaptable).


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## boyboykoi (Aug 22, 2013)

I'm doing the crush coral route I just started today but I don't know if it will even move my ph it's a 160g someone said online you should get pound for gallon but I think he's false but I don't know maybe someone here can answer that


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## fishman8888 (Mar 22, 2014)

Thank you all for the responses,

Think ill try the DIY method, seems like an interesting project.... is calcium chloride the same as calcium carbonate? ...

Do you know what store would have all those chemicals?/best prices?

Also....i was thinking a kh of around 5-6 would be the happy medium....but im open to suggestions if you think otherwise


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## 2wheelsx2 (Apr 21, 2010)

Crushed coral would dissolve faster and raise your KH more than you GH (and only Ca not Mg). Do like Rockman does and use dolomite. It will have both Mg and Ca and thus dissolve slower and maintain a more stable balance.


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## fishman8888 (Mar 22, 2014)

Where can you buy dolomite around here? Do you have to order it online? 

Would you put it in the tank? Filter? Or both?


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## 2wheelsx2 (Apr 21, 2010)

Any place that sell horticulture stuff, but you have to make sure it's pure dolomite with no other additives. I personally like to put my coral in my filter (I buffer GH with a GH booster and only use Coral for KH/pH). You can also put it in the bottom of whatever other substrate you want to use.


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## Rockman (May 19, 2013)

fishman8888 said:


> Where can you buy dolomite around here? Do you have to order it online?


It's not hard to find. The stuff I bought is Garden Pro Dolomite lime; which I believe came from one of the local nursaries. My 2 kg tub ($10) is probably a few years supply.

I put mine in my filter. You do have to replace it every so often; so putting in the tank is less useful.


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## fishman8888 (Mar 22, 2014)

Does that stuff not have binding agents in it? 
I saw that stuff at home depot...

Went to petland poco and theyre gunna order it for me


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## Rockman (May 19, 2013)

Nope... it's chipped, not granulated. Shouldn't have any binding agents.


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## 2wheelsx2 (Apr 21, 2010)

Rockman said:


> Nope... it's chipped, not granulated. Shouldn't have any binding agents.


Yep, dolomite is a rock. So just broken up rock. Even the rounded Dolopril stuff is just ground to round the sharpness off I believe.


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## Fish rookie (May 21, 2012)

Putting dolomite/crushed coral in the filter will work much better than just leaving in the tank.
I have seen oyster shells being used, they can be free. 
I buy my gH booster from Pat(mykiss) of Canadian Aquatic. He was nice enough to tailor it with the chemicals I wanted.
Calcium chloride is not the same as calcium carbonate. 
I am not 100% sure but I read that chloride ion can reduce the harmful effect of excess nitrite (may be nitrate but not sure). I cannot remember now but it has something to do with the oxygen absorbtion ability in the blood stream of the fish or something like that.
Calcium carbonate will probably increase your pH/kH. It will both give you a higher gH because of the Ca ion. 
Can you use calcium carbonate to increase both gH and kH, sort of killing two birds with one stone...has anyone tried it?
You can buy a bottle of Calcium Carbonate in the vitamin section for $2 at dollarama and just grind it with a coffee grinder may be...I would like to know what others think about that.


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## Rockman (May 19, 2013)

2wheelsx2 said:


> Yep, dolomite is a rock. So just broken up rock. Even the rounded Dolopril stuff is just ground to round the sharpness off I believe.


You'd think. Sometimes they powder it down though and make it into little pellets with a binding agent. I think the idea is to make it more soluble and faster acting as a lawn additive. I don't think the binders are toxic (although I'm not sure about that); but it's not really what you want.



Fish rookie said:


> Calcium chloride is not the same as calcium carbonate.


Correct. Calcium chloride doesn't have any effect on KH (since it contains chloride rather than carbonate), but will boost GH. Calcium carbonate raises both KH and GH. Calcium chloride (or sometimes calcium sulphate) is the calcium source for pretty much all commercial mineral additives; because it's cheap and easily dissolved.



Fish rookie said:


> I am not 100% sure but I read that chloride ion can reduce the harmful effect of excess nitrite (may be nitrate but not sure). I cannot remember now but it has something to do with the oxygen absorbtion ability in the blood stream of the fish or something like that.


Yep... chloride is good for nitrite posioning. The reason is that nitrite is absorbed in the same way as chloride. The nitrite and chloride compete with each other for uptake; so if you have lots of chloride in the water the nitrite isn't absorbed as much. The oxygen absorbtion bit has to do with what nitrite does in the bloodstream; it binds with hemoglobin and prevents it from binding with oxygen. In some ways it's similar to carbon monoxide posioning in humans.



Fish rookie said:


> Calcium carbonate will probably increase your pH/kH. It will both give you a higher gH because of the Ca ion.
> Can you use calcium carbonate to increase both gH and kH, sort of killing two birds with one stone...has anyone tried it?
> You can buy a bottle of Calcium Carbonate in the vitamin section for $2 at dollarama and just grind it with a coffee grinder may be...I would like to know what others think about that.


I've tried using powdered limestone (calcium carbonate) as a mineral additive. Problem is it doesn't dissolve at all compared to something like calcium chloride. Most if it sits at the bottom of whatever container you're mixing it in and you don't get much above a degree or two of hardness. It's not really practical to add it to replacement water. The best way to use calcium carbonate is as crushed coral in a filter (where the low solubility is an advantage).


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## 2wheelsx2 (Apr 21, 2010)

I use CaCO3 but the problem is that it's not readily soluble in water. CaCl dissolves much more readily. It's the carbonate component which makes it less readily soluble. Otherwise all the shells of the shell fish will just dissolve. 

Shells are usually not in the form of calcite, but in the form of aragonite, which has lower solubility.

As for working "better" it depends on your objective. If you are trying to achieve stable pH/KH/GH, I might disagree since forcing more water past it would cause faster changes in parameters which may not be better. Leaving it in the substrate would lead to slower dissolution, which may be better for growing plants and having greater stability, but may be worse if you're trying to keep Africans.

Edit: Got ninja'd by Rockman. As for the dolomite, anything they call "dolomite" would be rock. Even dolopril (tm) is just dolomite. I believe they can't call it dolomite if they use binders (or they have to qualify it) but then I'm not a gardening expert.


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## 2wheelsx2 (Apr 21, 2010)

Rockman said:


> Yep... chloride is good for nitrite posioning. The reason is that nitrite is absorbed in the same way as chloride. The nitrite and chloride compete with each other for uptake; so if you have lots of chloride in the water the nitrite isn't absorbed as much. The oxygen absorbtion bit has to do with what nitrite does in the bloodstream; it binds with hemoglobin and prevents it from binding with oxygen. In some ways it's similar to carbon monoxide posioning in humans.
> 
> I've tried using powdered limestone (calcium carbonate) as a mineral additive. Problem is it doesn't dissolve at all compared to something like calcium chloride. Most if it sits at the bottom of whatever container you're mixing it in and you don't get much above a degree or two of hardness. It's not really practical to add it to replacement water. The best way to use calcium carbonate is as crushed coral in a filter (where the low solubility is an advantage).


Nitrite poisoning would be fairly uncommon in the aquarium since it's usually a transition product between ammonia and nitrate. But for the reason that you describe, salt (NaCl) is used to relieve ammonia/nitrite poisoning during tank cycling. That's really the only time nitrite would be present in any amount in a tank (or maybe I spoke too soon since I see those cycling threads on here sometimes).

I use powdered calcium carbonate (chicken feed actually) regularly in my bare bottomed tank which has cherry shrimp (for obvious reasons) in my pleco growout tanks and they dissolve in a reasonable amount of time to achieve the TDS I need (100 ppm +/-). But you're right, if you throw a whole pile in there it'll just site there. After all, it's limestone.  If you throw a big block of limestone in a tank it's not going to dissolve away in days months or even years, depending on the size. Crushing it just increases the available surface area.

Edit: Oh I forgot to add that if you're having trouble dissolving calcium carbonate use cold water. Solubility of CaCO3 rises inversely with temperature. So throwing the CaCO3 into a tank of warm water would not dissolve it very quickly.


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## fishman8888 (Mar 22, 2014)

I do (2) 50% water changes every week 
.....would it be wiser to do daily 10-15% water changes with the crushed coral in my filters? Would that help in stabilizing the kh more efficiently? Or would you keep the two 50%'er schedule

Note: i dont mind the daily work....i love spending time with my little aquatic family

...also i have 3 hob filters on my tank...would you put it in all 3? Would that drastically affect the spike in kh/gh and the time it takes for it to occur?


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## 2wheelsx2 (Apr 21, 2010)

Doing smaller daily changes would certainly keep things more stable, but I don't think it would be effort effective for the small gains you would get.

I also do 2x50+% wc a week in some of my tanks (3x75% in my discus tank. The reason being to keep to organic wastes down. 10% every day over 7 days would net you a dilution rate of 7x10% cumulative over the week which, to use an example of 10 ppm nitrate a week would be 0.9^7 which would net you a total dilution rate of only 53% (simplified immensely assuming no introduction of new nitrate). Of course, it counteracts your nitrate gain daily, whereas 2x50% would net you a 75% dilution rate (again, simplified).

I think the answer depends on what GH/KH you are trying to achieve for which species. For discus and soft water species, then I would go for bigger wc with not so much buffering, but just enough to prevent pH crashes. If you are keeping Africans I would not do so many wc at all if you're trying to get the GH/KH up.


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