In order to get my water ready for my new tank, i bought crushed coral to put in the filter.. I tested it out in a bowl to see its effects on the water. The PH raised to about 8.9, which is perfect! The GH and KH stayed the same however. So i added epsom salt (i heard this is good for increasing hardness), but it only increased the GH, and not KH. Can anyone help me on this?
PH and GH are rising, but KH isn't!
- Thread starter mercsoulja
- Start date
Epsom salts will add magnesium which will increase GH but will have no effect on Kh or pH. GH is general hardness and the two primary elements the test picks up on are calcium and magnesium. Kh is a measure of Carbonate hardness which directly correlates with pH. The higher the Kh the higher the pH.
How long did you let the water sit before testing. It's quite possible that the change in pH you saw was a result of Co2 gassing off. Most tap water contains elevated Co2 levels and pH will increase after it sits out a while.
Crushed coral does not dissolve quickly at higher pH levels. it will take several days to see any real result from it. additionally it does not dissolve for me at all at pH higher than 7.6-7.8.
Dave
How long did you let the water sit before testing. It's quite possible that the change in pH you saw was a result of Co2 gassing off. Most tap water contains elevated Co2 levels and pH will increase after it sits out a while.
Crushed coral does not dissolve quickly at higher pH levels. it will take several days to see any real result from it. additionally it does not dissolve for me at all at pH higher than 7.6-7.8.
Dave
I agree with everything daveedka said. I may be wrong and if someone knows for sure that I am, please correct me, but I have figured that Gh is a measure of calcium/magnesium hardness and carbonate hardness. While calcium hardness is fairly permanent unless flora or fauna (duckweed, coral) absorbs it, carbonate is considerred a temporary source of hardness and that is why there is a Kh test. When you combine the two you can determine your stable hardness. So crushed coral is a good high pH/hardness buffer because it is mostly calcium?
GH is calcium and magnesium hardness (divalent cations), the mineral ions which make it difficult to create a foam with soap. Carbonate has nothing whatsoever to do with that and bicarbonate (HCO3-) and carbonate (CO3--) are monovalent and divalent anions, respectively. They are totally differnt ions from the Ca++/MG++ group. Daveedka is correct.
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epsom salt is magnesium sulfate. the magnesium will elevate the gH but sulfate has nothing to do with kH which is carbonate hardness.
I add baking soda to my Tang tanks to raise the KH and a combination of epsom salts and a little sea salt to raise the GH.
*EDIT* correction... I add it to the change water which mixes and filters for a week or so between water changes on the critter tanks. This allows me to get the water stable and to temp.
*EDIT* correction... I add it to the change water which mixes and filters for a week or so between water changes on the critter tanks. This allows me to get the water stable and to temp.
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So the crushed coral should have an effect on the carbonate hardness (KH)? I should probably just put it in my filter and see how it works, instead of testing in the cup.
Are there other ways to increase KH without changing PH?
Are there other ways to increase KH without changing PH?
KH and pH are directly correlated. If you increase KH you will see an increase in pH.
aside from Coral, there are many other forms of Calcim Carbonate that can be used. some dissolve faster than coral some slower. Either way coral will do the job it just does so slowly.
With the fish you are planning to keep Coral in the filter will provide a good stable environmentbecause it will replenish KH as it is consumed. Then if you add additional Calcium and Magnesium to harden the water GH wise your fish will be happy. To make this easiest on yourself and your fish, forget the pH number altogether, Find a number you like and can maintain for KH and GH and as long as those two are where you want them you'll be fine
Dave