Water Change pH

OgreMkV

Father of Earth's Next Emperor
Apr 26, 2007
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Port Arthur, TX
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How do you get the new salt water to the correct pH? My tap water is only slightly alkaline (7.2 - 7.4). My tank needs to be 8.2 - 8.4. Will just the process of mixing the salt water do that or do I have to add a buffer?

Thanks
 
The pH should be correct after the salt is dissolved. The tap water has very little buffering ability. If the pH isn't in an acceptable range after adding the salt, you should look into buying another brand of salt...
 
Most mixes, after settling for a while, will come to a pH within the range of 7.8-8.4, which is fine. I wouldn't bother trying to tweak pH, since it is too variable. The 8.2-8.4 range is unrealistically narrow for the vast majority of tanks. Besides, so long as the water isn't drastically different and the change quantity isn't terribly large, it shouldn't matter much.
 
i use red sea salt which brings my water from roughly a ph of 7.0.to 8.3....but i have to buffer my top up water.

Don't buffer the top off water. Fresh water has virtually no buffering ability itself (especially if it is RO/DI), so even it says it has a pH of 7.0, it won't affect your tank pH, as all the buffer salts in the tank will immediately compensate when you add the top off water.. The buffer salts that you're adding to the topoff water will remain behind as the water evaporates, so you're slowly increasing the concentration of these in your tank, and your SG will slowly climb.
 
Don't buffer the top off water. Fresh water has virtually no buffering ability itself (especially if it is RO/DI), so even it says it has a pH of 7.0, it won't affect your tank pH, as all the buffer salts in the tank will immediately compensate when you add the top off water.. The buffer salts that you're adding to the topoff water will remain behind as the water evaporates, so you're slowly increasing the concentration of these in your tank, and your SG will slowly climb.

Actually, if you measure RO/DI water, it is usually on the acidic side (usually in the 6s) due to absorption of atmospheric CO2. That is easily gassed off when added to the tank. I do agree, however, that it won't interfere with buffering capacity unless you add a lot of it at one time and dilute it.

I should also point out that one should consider the accuracy of pH test kits, as well. I wouldn't use anything other than a frequently recalibrated pH meter or some reliable kit, like Elos.
 
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