Understanding alkalinity and ph---the easy way.
Posted 07/04/2017 at 09:11 AM by Sk8r
"In chemistry, pH (potential of hydrogen) is a numeric scale used to specify the acidity or basicity of an aqueous solution."---wiki. Ie, is your water acidic like lemon juice---or alkaline like a desert pool?
On that scale, battery acid (ph of 1) and drain cleaner (ph of 12)---both extremes can burn.
Your tank should be between 7.9 and 9 for the comfort of fishy skin and gills.
BUT--- ph in a marine tank wanders all over the map during a given day. Pretty well toss your ph meter---it's only going to tell you how it is THIS hour.
SO---in the marine hobby---we track alkalinity.
What is alkalinity?
"Alkalinity refers to the capability of water to neutralize acid."---wiki.
It is essentially its 'buffering' capacity, buffer, as in---to soften...referring to its 'carbonate hardness' or dkh.
Stay with me: this is NOT rocket science: I'll explain.
"Carbonate hardness, or carbonate alkalinity, is a measure of the alkalinity of water [caused by the presence of carbonate (CO2− 3) and bicarbonate (HCO− 3) anions"...but you don't need to know that to use it]. Just say that you want, generally, a dkh of 8.3. It's a nice number. It can be safely as low as 7.9 or as high as 9.
You can test your dkh with an Alkalinity Test. I use Salifert, quickest and dirtiest of all water tests, which is good, because it's the one you should run weekly on ALL KINDS of tanks. [unless you're running kalk, in which case you track your magnesium level, but that's a whole other kettle of fish.]
If your alk is 8.3 or slightly either side of it (7.9 to 9.0) your alk is great, your fish are not swimming either in battery acid or drain cleaner, and that is ALL you need to track because dkh actually measures how able your water is to keep the water safe and comfy. Tracking ph will drive you crazy. Track alk: it's a much more stable number, and SHOULD stay rock-steady. That's your job. To affect alk, you add buffer. Your general danger is water that's too acidic...so you just keep that buffer level right in that ballpark and you are good.
On that scale, battery acid (ph of 1) and drain cleaner (ph of 12)---both extremes can burn.
Your tank should be between 7.9 and 9 for the comfort of fishy skin and gills.
BUT--- ph in a marine tank wanders all over the map during a given day. Pretty well toss your ph meter---it's only going to tell you how it is THIS hour.
SO---in the marine hobby---we track alkalinity.
What is alkalinity?
"Alkalinity refers to the capability of water to neutralize acid."---wiki.
It is essentially its 'buffering' capacity, buffer, as in---to soften...referring to its 'carbonate hardness' or dkh.
Stay with me: this is NOT rocket science: I'll explain.
"Carbonate hardness, or carbonate alkalinity, is a measure of the alkalinity of water [caused by the presence of carbonate (CO2− 3) and bicarbonate (HCO− 3) anions"...but you don't need to know that to use it]. Just say that you want, generally, a dkh of 8.3. It's a nice number. It can be safely as low as 7.9 or as high as 9.
You can test your dkh with an Alkalinity Test. I use Salifert, quickest and dirtiest of all water tests, which is good, because it's the one you should run weekly on ALL KINDS of tanks. [unless you're running kalk, in which case you track your magnesium level, but that's a whole other kettle of fish.]
If your alk is 8.3 or slightly either side of it (7.9 to 9.0) your alk is great, your fish are not swimming either in battery acid or drain cleaner, and that is ALL you need to track because dkh actually measures how able your water is to keep the water safe and comfy. Tracking ph will drive you crazy. Track alk: it's a much more stable number, and SHOULD stay rock-steady. That's your job. To affect alk, you add buffer. Your general danger is water that's too acidic...so you just keep that buffer level right in that ballpark and you are good.
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