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Old 05/18/2019, 04:11 AM   #1
dava6711
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Calcium & Alkalinity Issues

Hi

This is making me rip my hair out in frustration.

I have a reefer 170 tank, it’s stocked with a single Macrodactyla doreensis anemone, a selection of three small fish, royal gramma, clown fish & a bangaii cardinal & a selection of macroalgae.

The display tank is lit by a single 150w metal halide (20k bulb, on for 8 hours a day).

Biological filtration is accomplished by a fluidised sand filter in the sump.

Current parameters are:-
Calcium: 320ppm.
Alkalinity: 8dKH.
Magnesium: 1080ppm.
Nitrate: trace.
(I know that calcium & magnesium are too low).

My rate of alkalinity depletion is unreal, like 1dKH a day. In an attempt to maintain my alkalinity I’m using saturated calcium hydroxide for all top off water, this is only stopping the alkalinity from being depleted as fast, calcium hydroxide alone is unable to maintain, I’m having to supplement with sodium bicarbonate alongside the calcium hydroxide.

How can other aquarists maintain their large, fully fledged reef tanks calcium and alkalinity demands using calcium hydroxide, but I can't accomplish this on a reefer 170 (approximately 43 gallons) with no hard corals or live rock?

If my calcium was super saturated I understand I’d have difficulty raising the alkalinity as I’d have a precipitation event, but I'm able to raise the alkalinity easily with my calcium being so low, testing after adding sodium bicarbonate confirms the increase in alkalinity but it still gets depleted so quickly.

I have no live rock, and no hard coral. Just 3 small fish, an anemone (very healthy) and macroalgae, that’s it.

So how is it being depleted so fast with no live rock, and no hard corals (or even soft corals for that matter), just the anemone and three fish?

Any help will be greatly appreciated.



Last edited by dava6711; 05/18/2019 at 04:33 AM.
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Old 05/18/2019, 09:00 AM   #2
dubmaneh
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You may be dosing too much alkalinity. IME dosing too much has the effect of actually lowering it because it will precipitate onto heaters, pumps etc.

How did you test your demand?


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Old 05/18/2019, 10:59 AM   #3
dava6711
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[QUOTE=dubmaneh;25590045]You may be dosing too much alkalinity. IME dosing too much has the effect of actually lowering it because it will precipitate onto heaters, pumps etc.

How did you test your demand?

Confirmed the rate of depletion by daily testing, recording the results & observing weekly trends.


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Old 05/18/2019, 12:13 PM   #4
hegeh
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Less is more. Is your solution of ALk correct? I had the same issue previously. But i learned i was mixing the wrong ratio and caused the calcium to percipitate. They chase each other as i tries to bring up the calcium. Finally i settled with Aquaforest KH buffer when my previous of DIY alk solution used up. Lesson learned is i might have my calculation wrong or i bake my sodium bicarbonate wrongly.

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Old 05/18/2019, 05:34 PM   #5
bertoni
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1 dKH per day along with Kalk topoff is credible. My soft coral tanks went through more than that due to coralline growth alone. How long has the the tank been running? Often, new sandbeds and rock seem to provide a lot of nucleation sites that encourage abiotic precipitation.


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Old 05/19/2019, 02:09 AM   #6
dava6711
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Quote:
Originally Posted by bertoni View Post
1 dKH per day along with Kalk topoff is credible. My soft coral tanks went through more than that due to coralline growth alone. How long has the the tank been running? Often, new sandbeds and rock seem to provide a lot of nucleation sites that encourage abiotic precipitation.
Interesting, Iíd never heard of that. Itís been running for around 6 months so your theory does sound like a possibility.

Iím gonna stop using Kalk and continue using bicarbonate & calcium chloride then as I donít like the mess the Kalk has been making in my sump.


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Old 05/19/2019, 04:20 PM   #7
bertoni
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Maybe a fair amount of the Kalk is precipitating?


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Old 05/19/2019, 04:37 PM   #8
dava6711
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Quote:
Originally Posted by bertoni View Post
Maybe a fair amount of the Kalk is precipitating?
Only in the fresh water reservoir & on the float valve.

Note, I wasnít using kalk at first. Iíve only been using it about a month or so in an attempt to prevent my alkalinity swings. This has been an ongoing issue.

Iím gonna try leaving the alkalinity for a few days. Refrain from both testing & supplementing and observe the tank carefully, if I remember rightly it never seemed to drop below 7.7dKH.


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Old 05/19/2019, 06:35 PM   #9
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Okay, that seems reasonable. Good luck!


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