Alk consumption increased
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Randy Holmes-Farley
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No, that is not exactly true.
If you lowered alkalinity by adding acid, it had no immediate impact on calcium in that water. It will reduce the likelihood of precipitating calcium carbonate in the future, which will reduce the likelihood of alkalinity and calcium dropping further.
I also do not think the difference between 470 ppm calcium and 420 ppm calcium will make any noticeable change in the demand for calcium and alkalinity going forward.
In terms of the precipitation of calcium carbonate, a change of only 0.1 pH unit has a bigger effect than a change in calcium from 520 to 420 ppm. pH is a big driver.
That said, the OP change in demand is fairly small and need not have anything unusual going on, IMO.
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reefndude
Valuable Member
PH ranges from 7.9-8.3 through out the dayNo, that is not exactly true.
If you lowered alkalinity by adding acid, it had no immediate impact on calcium in that water. It will reduce the likelihood of precipitating calcium carbonate in the future, which will reduce the likelihood of alkalinity and calcium dropping further.
I also do not think the difference between 470 ppm calcium and 420 ppm calcium will make any noticeable change in the demand for calcium and alkalinity going forward.
In terms of the precipitation of calcium carbonate, a change of only 0.1 pH unit has a bigger effect than a change in calcium from 520 to 420 ppm. pH is a big driver.
That said, the OP change in demand is fairly small and need not have anything unusual going on, IMO.
jcdeng
Valuable Member
do you run large amount of gfo on your tank? they tend to decrease alk especially when they are new. 78ml for your size tank is acceptable. I used to dose 28ml daily on my tank and didn't check alk for a good while, but when I get off my lazy butt to check it, it was at 6.2. So now I increased it to 35ml daily. I use a lot of rowa btw so that contributes to a lower than desired alk lvl.
rovster
Well-Known Member
Tread with caution. Be sure that your tester is accurate. I recently had an issue with my Hanna checker where it was reading much lower alkalinity then what was really in the tank. That led me to artificially raise the alkalinity and caused all kinds of issues. After some research and it seems that this is quite common with the alkalinity checker. It's more common as you get towards the end of the reagent bottle. My dropping of alkalinity coincided with a pretty decent growth spurt so I had no reason to doubt the results.
I'm not saying that this is the case here but I would definitely consider verifying your test results be going before going any further. Hope this helps.
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reefndude
Valuable Member
Thanks for the heads up. As far as I can tell it is accurate. I also checked new salt water and it was right on where it should be. I will also double check with my red sea kit to see if it is in the same ball park. Thanks again
rovster
Well-Known Member
No problem. I love my checker and they are incredibly consistent. I did buy myself a back up Salifert kit for verification anytime I see my alk dip going forward. In my tank it was particularly problematic because I carbon dose and run a low nutrient system.
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reefndude
Valuable Member
I love the hanna checkers as well...the alk and phosphates anyways. My tank was very low nutrients until my sand bed shifted...bone head mistake. Since that happened nitrates shot up, Phosphates went up as well. Been working on it for a month now to get it back to my liking.
