Calcium not being uptaken by corals

[ZaydRossi]

Hey Guys,

My calcium has been sitting at 470 for the past 5 weeks and doesnt seem to be lowering at all. Previous to that my Ca was needing to be topped regularly to maintain.
Im thinking this is due to the Ca being too high? Usually i shoot for 450-470.

Current Perimeters
Temp: 25 Degrees C
Salinity. 1.025SG
Nitrate: 3.40 ppm
PH: 8ph
Ca: 470
Alk: 11
Phos: 0.21ppm

Any ideas on why this is happening are welcome. No wrong answer, just wanting to colate some different opinions.

 

[shwareefer]

What size tank, what kind of corals and how many, what do you dose, how are you measuring?

 

[nereefpat]

Any ideas on why this is happening are welcome. No wrong answer, just wanting to colate some different opinions.

Likely just limits of your test kit. Our kits are mostly about +/- 20ppm for Ca.

If you know how much your alkalinity in dKH usage is per day, Ca will be about 7 ppm per dKH of alk. So the tank would have to consume about 6 dKH before you could reliably notice that on a test kit.

470 ppm is a fine place to be.

 

[jda]

Main consumer of calcium and carbonate is coralline. Do you have a good amount? If so, has it slowed down? For me, coralline will slow down once po4 gets over .05, or so... not stop, but slow down.

 

[ZaydRossi]

What size tank, what kind of corals and how many, what do you dose, how are you measuring?

The tank is a 132 gallon (500L). Moderately stocked with LPS corals. No SPS. I dont dose daily, i prefer to dose weekly alk. will go between 11.5dkh - 9.7dkh per week. Do you think the AlK swing is too much? Corals seem to be doing fine with that and always have been. Tank is about 1.5 years old now.

 

[ZaydRossi]

Likely just limits of your test kit. Our kits are mostly about +/- 20ppm for Ca.

If you know how much your alkalinity in dKH usage is per day, Ca will be about 7 ppm per dKH of alk. So the tank would have to consume about 6 dKH before you could reliably notice that on a test kit.

470 ppm is a fine place to be.

I test Mag with Aquaforest test kit and Alk, Ca with salifert. Ive found this combination is the most accurate. Corals seem to be doing fine but just not noticing any changes in Ca measurements anymore, i use to be able to see the drop weekly with Ca but about 5 weeks ago that stopped.

 

[ZaydRossi]

Main consumer of calcium and carbonate is coralline. Do you have a good amount? If so, has it slowed down? For me, coralline will slow down once po4 gets over .05, or so... not stop, but slow down.

Coraline growth has slowed down. Im gathering that is due to the higher point of sale at 0.1-0.2

 

[bushdoc]

My theory is that your Ca consumption is low and difficult to detect with hobby test kits.
I wouldn't worry to much about it.
I would though test and dose alkalinity more often then once a week.
Once a week dosing of Alkalinity might be a bit stressful on your corals.

 

[ZaydRossi]

My theory is that your Ca consumption is low and difficult to detect with hobby test kits.
I wouldn't worry to much about it.
I would though test and dose alkalinity more often then once a week.
Once a week dosing of Alkalinity might be a bit stressful on your corals.

Might have to set up my auto doser. Never used it. Whats the best way to do so?

 

[bushdoc]

Might have to set up my auto doser. Never used it. Whats the best way to do so?

You need to establish dKH consumption by stopping any dosing and measuring alkalinity same time ot the day in two consecutive days. Then you can use BRS (or other) calculator to dose supplemenmt of your choice.Generally it's the best to dose alkalinity in several smaller aliquots spread over 24h. Calcium you can dose less frequently and Mg once a week or so.

 

[ZaydRossi]

You need to establish dKH consumption by stopping any dosing and measuring alkalinity same time ot the day in two consecutive days. Then you can use BRS (or other) calculator to dose supplemenmt of your choice.Generally it's the best to dose alkalinity in several smaller aliquots spread over 24h. Calcium you can dose less frequently and Mg once a week or so.

Thanks for that. Sounds like it would be a good idea. Spent all this money on a doser that im not using

 

[nereefpat]

If the tank consumes 11.5 - 9.7 dKH per week, that is 0.26 dKH per day.

You can easily dose that much with kalk only. I would probably start by replacing the evaporated water with 1/2 strength kalk (1 teaspoon per gallon)

 

[KStatefan]

If the tank consumes 11.5 - 9.7 dKH per week, that is 0.26 dKH per day.

You can easily dose that much with kalk only. I would probably start by replacing the evaporated water with 1/2 strength kalk (1 teaspoon per gallon)

I think that is his alk level swing during the week so 1.8dKH per week.