Calcium & Alkalinity Issues

[dava6711]

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.

 

[dubmaneh]

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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[dava6711]

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.

 

[hegeh]

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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[bertoni]

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.

 

[dava6711]

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, I'd never heard of that. It's been running for around 6 months so your theory does sound like a possibility.

I'm gonna stop using Kalk and continue using bicarbonate & calcium chloride then as I don't like the mess the Kalk has been making in my sump.

 

[bertoni]

Maybe a fair amount of the Kalk is precipitating?

 

[dava6711]

Maybe a fair amount of the Kalk is precipitating?

Only in the fresh water reservoir & on the float valve.

Note, I wasn't using kalk at first. I've only been using it about a month or so in an attempt to prevent my alkalinity swings. This has been an ongoing issue.

I'm 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.

 

[bertoni]

Okay, that seems reasonable. Good luck!

 

[Uncle99]

I just don't understand why you dose anything if you have nothing that uses it?

Notwithstanding, your likely getting a false reading as your MG is too low.

Not that you need too but if you want to maintain Stoney coral water chemistry, I would increase your MG to 1260-1360 ppm, otherwise the Alk ion and the CA ion will come together to fast. Your a bit to low in my mind. MG purpose is to make both those calcification ions less attracted to each other and stay in the solution to be used by Stoneys.

Otherwise they just come together quickly and precipitate out leaving a low level when testing.

 

[dava6711]

I just don't understand why you dose anything if you have nothing that uses it?

Notwithstanding, your likely getting a false reading as your MG is too low.

Not that you need too but if you want to maintain Stoney coral water chemistry, I would increase your MG to 1260-1360 ppm, otherwise the Alk ion and the CA ion will come together to fast. Your a bit to low in my mind. MG purpose is to make both those calcification ions less attracted to each other and stay in the solution to be used by Stoneys.

Otherwise they just come together quickly and precipitate out leaving a low level when testing.

I'm dosing to replicate their environmental conditions.

I realise my magnesium is low but never realised it was as important as it obviously is to manitain a stable calcium and alkalinity.

In order to get my magnesium to the ideal level, I need to dose approximately 450 grams, dosing that much absolutely can't be good for my water chemistry, it's surely gonna increase my salinity significantly! I guess I could increase it extremely gradually.

 

[bertoni]

Magnesium at 1080 ppm is a bit low, but not that bad. I ran tanks at that level for years because IO came at that level for a long time. The low magnesium level will not affect test kit results.

 

[Uncle99]

I’m dosing to replicate their environmental conditions.

I realise my magnesium is low but never realised it was as important as it obviously is to manitain a stable calcium and alkalinity.

In order to get my magnesium to the ideal level, I need to dose approximately 450 grams, dosing that much absolutely can’t be good for my water chemistry, it’s surely gonna increase my salinity significantly! I guess I could increase it extremely gradually.

I struggled with maintaining CA and Alk for quite some time until a member guided me on the keeping MG on point. Since I followed this direction, CA and Alk have been easy to maintain.

For me, anything below 1100 ppm seemed to bring varied testing results for Alk.

I maintain 1320-1360 ppm for 28 months now, and with hourly dosing of Alk, the flux is 10ppm at any time.

Slow increase.....absolutely....and that applies to everything.....say 20-30ppm every other day is fine.....

While levels are important.....consistency is everything

 

[hkgar]

I would raise mag to at least 1250. I like to keep mine at 1400+

 

[dava6711]

Update

After slowly increasing magnesium to 1320mg/L using magnesium chloride, and calcium to 420ppm using anhydrous calcium chloride my alkalinity has remained rock solid at 8.3dKH.

So it appears that all the suggestions on this thread recommending I increase magnesium were indeed correct.

My parameters have been absolutely rock solid & stable.

Nitrate: trace.
Magnesium: 1320mg/L.
Calcium: 420ppm.
Alkalinity: 8.3dKH.

I want to thank all the members who posted in this thread.

 

[Uncle99]

And that is excellent news!
Thanks for keeping us in the loop.

 

[dava6711]

And that is excellent news!
Thanks for keeping us in the loop.

That's why I updated, I've seen so many threads created with no updates or any sign of closure from the OP.

I'm slightly embarrassed that I had to create a thread about my issues maintaining a stable alkalinity when the resolution was so simple!

 

[TwoShoesOrOne]

Hi,
My dkh is way too high ( 13.4 in my opinion). First I thought about the salt mixture I am using (IO) which is supposed to make 11 dkh. What is making it more in my tank and how can I fix it.

Thank you

 

[TwoShoesOrOne]

Sorry should have been new thread

 

[dava6711]

Hi,
My dkh is way too high ( 13.4 in my opinion). First I thought about the salt mixture I am using (IO) which is supposed to make 11 dkh. What is making it more in my tank and how can I fix it.

Thank you

Your fix is an easy one.

If your calcium and magnesium are both at the correct parameters, and your elevated alkalinity isn't causing any problems to your livestock, I'd simply leave it to come down on its own over time.