Does anyone add a buffer to their top off water to bring the PH closer to that of the tank? If so what do you use and what could I use if I just wanted to make 1 Gallon of top off water. Thanks.
Buffering RODI Water?
- Thread starter BlazinNano
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MrZ
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I've heard many people ask that question, but there is no need. RO/DI is just about as close to pure water as we can manage. It has no PH. There needs to be something dissolved in water (impurities) for it to register anything on the PH scale. This means that RO/DI water will instantly take on the PH of whatever solution it is added to (our tank water in this case). If you measure the PH of pure RODI water it will always be a false reading. If you are curious about this and want to test it out, take a cup of RODI water and put in the smallest drop of vinegar and measure its PH. Then take a fresh cup of RODI water and put in the smallest pinch of baking soda measuring that PH. You'll see that it the first will measure an acid, (PH below 7). The second will measure a base (PH above 7). The RODI will take on the acidity or basic nature of whatever you put in it, it has no PH of its own. PH by definition is the ratio of H+ to OH- ions. Adding something to our tank water which has balanced H+ and OH- ions (like pure H2O) will not change that ratio in the slightest.
The only reason you would doctor your top off water is if you are continuously deficient in something necessary in your tank. If you added a buffer (such as sodium bicarbonate), you would end raising the PH of your tank over the long haul, and you would start tipping the ratio of carbonate versus calcium to the point of calcium deficency.
Now, one thing that might work for you is to add a very low concentration of kalkwasser (pickling lime) to your top off water. Kalkwasser will react with the CO2 dissolved in your tank water to form Calcium and Carbonate ions in the exact proportion needed for coral growth. This is something most of us can use. Because the kalkwasser will "use up" some of the CO2 in your tank water it will have the immediate effect of lowering your tanks PH (toward the alkaline side of the spectrum) if you put too much in at once. As new CO2 is dissolved in the water it would then return to normal PH. To avoid these spikes in PH you would need to have some method of slowly dripping your makeup water doctored with pickling lime rather than making up a gallon and dumping it in all at once.
So no, you should not add any buffer to your RODI water correct its PH, as it has no PH (anything you measured would be a false reading on your meter or test kit), but you might add something to your top off water as a calcium and carbonate replacement strategy.
Rob
The only reason you would doctor your top off water is if you are continuously deficient in something necessary in your tank. If you added a buffer (such as sodium bicarbonate), you would end raising the PH of your tank over the long haul, and you would start tipping the ratio of carbonate versus calcium to the point of calcium deficency.
Now, one thing that might work for you is to add a very low concentration of kalkwasser (pickling lime) to your top off water. Kalkwasser will react with the CO2 dissolved in your tank water to form Calcium and Carbonate ions in the exact proportion needed for coral growth. This is something most of us can use. Because the kalkwasser will "use up" some of the CO2 in your tank water it will have the immediate effect of lowering your tanks PH (toward the alkaline side of the spectrum) if you put too much in at once. As new CO2 is dissolved in the water it would then return to normal PH. To avoid these spikes in PH you would need to have some method of slowly dripping your makeup water doctored with pickling lime rather than making up a gallon and dumping it in all at once.
So no, you should not add any buffer to your RODI water correct its PH, as it has no PH (anything you measured would be a false reading on your meter or test kit), but you might add something to your top off water as a calcium and carbonate replacement strategy.
Rob
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