issue with maintaining calcium

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02tts

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Jul 18, 2008
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folks, need some help please...I have a 265G tank in which I dose kalk using a drip system of about 2 drops per second, this maintains my pH at around 8.15 (night) to 8.20 (day) but it seems I'm not able to raise my calcium levels past 370-380, I have checked my magnesium levels and they were low, 960, so I raised it over a week to 1320 but I'm still having issues maintaining high calcium: with 1320 mag and 3.75meq/l or 10.5dkh I still can not seem to raise it over 370, even if I put in something like turbo calcium, which not only lowers my alk, but also lowers my calcium to 320!?!?!?

BTW, I use a Salifert test to test magnesium, an instant ocean and natureef to measure alkalinity.


So:

1. does magnesium go down overnight/weekly - is this something that I should be testing daily and/or dosing daily/weekly?

2. am I not dripping enough kalk (when I meausure the saturated solution it measures at 1500+ on the calcium and 12.89 in pH - I have digital meters for both, they are new and calibrated - chemical tests show the same results)....? should I be dosing more?

3. if I were dosing too much kalk, which I don't think based on the size of tank and drip speed, but if I were, would that bring my calcium and magnesium down?


other values:

phosphates - 0
temperature - 79 degrees
salinity 1.021 - measured using refratometer and digital meter
nitrites - 0 - measured used nutrfin kit and also instant ocean
nitrates 10 - measured using nutrafin kit and also have digital meter
lights on for 8 hours a day

any help would be immensly appreciated!

also, there is currently NO live rock or corals in the tank, only fish and a dry aragonite substrate, before anyone asks, reason for calcium concern is because I want to grow the coraline algae as this is a fish only tank.

last but not least, I have some of the hairline algea growing in the glass and overflows....which I can't seem to understand how given the water chemistry, specially dosing kalk which neutralizes phosphates and also doing protein skimming (and I'm not using any phosphate sponges or the sort).
 

Amphiprion

Contain the Excitement...
Feb 14, 2007
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Mobile, Alabama
Real Name
Andrew
folks, need some help please...I have a 265G tank in which I dose kalk using a drip system of about 2 drops per second, this maintains my pH at around 8.15 (night) to 8.20 (day) but it seems I'm not able to raise my calcium levels past 370-380, I have checked my magnesium levels and they were low, 960, so I raised it over a week to 1320 but I'm still having issues maintaining high calcium: with 1320 mag and 3.75meq/l or 10.5dkh I still can not seem to raise it over 370, even if I put in something like turbo calcium, which not only lowers my alk, but also lowers my calcium to 320!?!?!?

You are experiencing a precipitation reaction. It isn't the gigantic snowglobe effect, but by adding more to an already supersaturated solution (for that particular Mg concentration and salinity), you simply make everything drop out.

BTW, I use a Salifert test to test magnesium, an instant ocean and natureef to measure alkalinity.

Okay.


So:

1. does magnesium go down overnight/weekly - is this something that I should be testing daily and/or dosing daily/weekly?

It only drops quickly/significantly when there is precipitation. Kalkwasser also results in a net drop in magnesium as calcium and alkalinity ions are used for calcification.

2. am I not dripping enough kalk (when I meausure the saturated solution it measures at 1500+ on the calcium and 12.89 in pH - I have digital meters for both, they are new and calibrated - chemical tests show the same results)....? should I be dosing more?

No. Right now, you have reached an "unbalanced" state in which, while completely supersaturated, you have relatively low levels of calcium and relatively high alkalinity.

3. if I were dosing too much kalk, which I don't think based on the size of tank and drip speed, but if I were, would that bring my calcium and magnesium down?

See all of the above.


other values:

phosphates - 0 Good
temperature - 79 degrees Okay
salinity 1.021 - measured using refratometer and digital meter (This value is too low to get maximum calcium and alkalinity solubility and may be part or all of the problem, . If you are aiming for NSW levels of both, get that specific gravity up to NSW levels, as well--1.0264 @77 Fahrenheit, or ~35ppt.)
nitrites - 0 - measured used nutrfin kit and also instant ocean
nitrates 10 - measured using nutrafin kit and also have digital meter
lights on for 8 hours a day

any help would be immensly appreciated!

also, there is currently NO live rock or corals in the tank, only fish and a dry aragonite substrate, before anyone asks, reason for calcium concern is because I want to grow the coraline algae as this is a fish only tank.

last but not least, I have some of the hairline algea growing in the glass and overflows....which I can't seem to understand how given the water chemistry, specially dosing kalk which neutralizes phosphates and also doing protein skimming (and I'm not using any phosphate sponges or the sort).

You will still have phosphate (and you obviously have some nitrate) regardless of what a test reads. That is enough to let algae grow. You will always have some algae somewhere, whether that is the glass or elsewhere.

See my reply in red.
 

fsn77

AC Moderators
Staff member
Feb 22, 2006
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SC
Well... I started this a bit ago, but I now see Amphiprion jumped in before I hit submit... I didn't see his comments before making my own.

I apologize for not having real specific answers for you, but I'll share my thoughts...

1) Magnesium should not fluxuate that much on a daily time scale. Low magnesium does not develop overnight or generally even over several days. Magnesium tends to deplete over the course of weeks, not days.

2) You may not be dripping enough kalk... but I can't say for sure either way on this one.

3) If you were dosing too much kalk, I would expect to see your alkalinity drop. Are you noticing any white, milky precipitate anywhere?

Having any issues with calcification on any of the impellars in your pumps / powerheads?

As for the algae, it's possible to have nuissance algae despite the test results showing 0 or near 0. Test kits only measure available nutrient concentrations in the water, without providing any indication as to how much has been processed by the algae. It takes very little phosphate (relative to nitrate) to satisfy algae. And, at this point, since the algae is already present, it's likely taking up the nutrients as fast as you are putting them into the tank, which is why you get readings at or near 0 for your nutrient tests. This is why the best method of algae control is physical removal. By removing the algae all together, the algae itself is obviously gone, but so are all the nutrients the algae processed, with no chance of the algae breaking down in the tank and releasing those nutrients back into the water.
 

02tts

AC Members
Jul 18, 2008
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thank you both for the insight...I'm going to try to raise the salinity to 1.024 as I believe this will (hopefully) solve my issue while keeping an alk of 3 - 3.25 meq/l.
 

snailrider

AC Members
Oct 30, 2007
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davesbmw.com
I am slightly puzzled No rock? Dry sand? This is just water sand 1.021 salinity?

What is causing your ph alk fluctuations in the first place? How much coraline is there now? What would happen if you quit dosing for a week?

So I tested my 55 for calcium today, (I like my snails and such) and mine was at 460. I use the seachem #28 and the one was dissolved so I figured I was ready for another. Evidently not.

Is your sandbed getting crusted or solid in spots? Dig around and see what your sand feels like. If your not consuming the calcium it has to be going somewhere. What water changes? If it settles into the sandbed and hardens it, that will only add to the buffer troubles.

Are you sugar or alcohol dosing? These can mess with ph alk. I accidentally (well not really) sugar dosed and it took quite awhile to get everything back stable. (don't give your fish tums)

For a tank of this size 265 gallons, if you are going to grow lots of calcium rich things, you probably should be looking into a calcium reactor. I hear nothing but good about them.

Good luck, and after you raise the salinity, consider just letting things settle down for awhile. Maybe throw #28 in.

Good luck
 
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