Alkalinity Spike

[bertoni]

Some alkalinity supplements will raise the pH temporarily by consuming carbon dioxide from the water column. Kalk is best at that, but it's still hard to drive the pH up that much with Kalk. The difference in pH due to alkalinity alone is very small in the 7-11 dKH range. This article has a couple of charts:

http://reefkeeping.com/issues/2004-09/rhf/index.htm

Even 14-19 dKH should be lower than 9.

[Potatohead]

Originally Posted by ssick92

Won't a tank with extremely high alk typically have extremely high pH also? I was always under the impression it was best to dose alk at night to not raise the pH too much...

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Depends on what you're dosing. Sodium bicarbonate will raise ph but you would have to dose a lot. Sodium carbonate will actually lower it... Both are widely used.

[bertoni]

Actually, it's the other way around. Sodium bicarbonate will lower the pH very slightly when added. Sodium carbonate will raise the pH.

[Mghanayem]

Originally Posted by ssick92

Strange...

You said the tank has been up and running for 6 years. Was anything changed prior to this or have you always had high alk? Have you tested your ATO water just to double check it isn't something with your RO system?

As weird as it is, you could even try to test your vibrance supplement mixed with RO water. Not sure if it will read accurately whatsoever, but could lend some insight I suppose...

Keep testing on a daily basis to see how quickly it goes up. Temporarily stop dosing aqua vitro and continue to test, see if you can find any correlation.

I think mixing the additive to the RO is genius! Thank you, and yes the tank has been up for 6 years, but it was always a FOWLR system, so I never cared to test the ALK

[ssick92]

Originally Posted by bertoni

Actually, it's the other way around. Sodium bicarbonate will lower the pH very slightly when added. Sodium carbonate will raise the pH.

Ahh, good to know. Thanks!