Importance of GH over pH in Freshwater Fish Aquaria

[ClownLurch]

Ooooh so X-ray tetras could be ok in my liquid rock?

 

[StevenF]

We need to keep in mind there is a difference between the KH boosters we buy and the KH naturally pressent in a stream.

THe majority of KH in most streams is from calcium (Ca) carbonate and magnesium (Mg) .The calcium and magnesium boost GH while the carbonate boost KH. carbonate. The KH you buy is sodium Na) bicarbonate or potassium (K) bicarbonate. they are very different . Why don't we use what Calcium carbonate and magnesium carbonat in KH booster? Simple calcium carbonate and magnesium carbonate have zero solubility at PH of 7 or higher. They only desolve in water with a PH of less than 7. Sodium and potassium bicarbonates in comparison will resolve at all PH levels.

These KH compounds also have a vey different affect on PH.

• Ca / Mg carbonate neutralize acids which will push the PH below 7. At A PH above 7 these compounds become insoluble dust floatinginthe water. So at a PH of 7 to 12 they will not push the PH Up. So ideally pure fresh water the PH with Ca / Mg carbonate the PH will stay at very close to 7. Other elements the water like sodiium potassium chloride salts can however change the solubility of Ca /Mg carbonate which will change the PH. For example, sea water has a PH of 8.
• Na / K bicarbonates however are soluble at all PH levels in water so they can push the PH uneven if thePH states at 8 before the bicarbonates are added. they will also alter the balance of sodium and potassium in the water. Boosting any aquaium KH by 3 degrees will push sodium levels up to 24 PPM and has no effect on GH.

So IF you adjust KH in an aquarium with Na / K carbonates you hold have very high levels of Na or K and a sever Na / K imbalance. These imbalances can seriously impact osmotic ballance of the fluids in the fish which does affect Kidney function. Using Ca / Mg carbonates however does not effect sodium and potassium .

Also it should be noted that none of the compound listed above will prevent PH from going up in an aquarium. Theyohlly prevent it from going down.

In my aquarium with RO water I have added s sea shell (solid carbonate) in my aquarium filter. The Ca / Mg in the shell will dissolve when PH drops. As a result my PH is stable at 7.

Also note that GH booster are typically made from a mix of Ca / Mg sulfate or Ca / Mg chlorides. These compounds by themselves do not affect PH. But plants need a lot of Ca Mg but very low levels of sulfur and chloride. So as plants consume Ca and Mg from the water excess sulfates and chlorides will build up on the water and those will push the PH down. If no action is taken in my RO tank the PH would drop gradually to a PH of 5. The seashell I put in my prevents the buildup of sulfates and chlorides.

When you try to match PH GH and KH values of a stream or lake Don't use commercial PH KH and PH products to do it. In the end you might match the paragmeters of the original water source but the water chemistry will be very different. You are better off getting ICP-OES water test on the original Waterloo get the levels 33 elements that are typically found i water and then add elements as necessary to RO to match the measured ICP / OES levels of the original water. The results will likely not be a perfect match but it would be much closer than trying to match P GH and KH with commercial products.