Big Alk and Cal drop during cycle

[Aquajan]

Hi,

I've just meshured my new tank witch is running for 1 month now.
And I noticed my alkalinity and calcium are way off while magnesium is as it should be..

The meshurement results are:

Kh 7.5 rs pro salif hanna
Ca 350 rs pro salif
Mag 1440 rs pro
No3 10 rs pro
Po4 0.067 hanna
Salinity 35 ppt refracto
Ph 8.15 probe
Temp 25°c probe

I have done multiple meshurements with similar results.

I have used red sea coral pro salt at 35 ppt.
I do 10% pw AWC for 1 week now and the container is filled with salt water for 2 weeks now and the water in the container has an Alk of 10.9 and ca of 450.
The tank is 90g total water volume.
I have 20 kg artificial rock of aquaforest 1 kg of maxpect spheres and 1 brick of marine pure.
I have an auto feeder that's feed some flakes every day.
I run a Skimmer and all the pumps no light (had carton board around the tank until yesterday to keep ambient light out).
I have dosed bacteria of fauna marine and the nyos balls.

Now I have read that nitrification takes up Alk but that's about 2.3 Alk for 50 ppm no3....
I only have 10 ppm no3 that can't be happening here.

Could it be participation somehow?
I have mixed the water in a container and followed red sea's mixing instructions.

 

[Randy Holmes-Farley Verified Community Expert]

I don’t believe the calcium dropped that much unless you have been adding alkalinity (the alk did not drop nearly enough to account for a 100 ppm calcium drop), but it is certainly possible there has been a small amount of calcium carbonate precipitation, along with a possible drop in alk due to cycling and production of nitrate.

 

[Aquajan]

Thanks for the reply.

I didn't add Alk to the tank only a 10%wc over the past week.

I measured the tank water ca 4 times with 2 test sets witch are both new and Alk 5 times with 3 test sets.
I tested the container water 2 times on ca and Alk and that salt is from the same bucket as the tank.

Could it be possible that the calcium is absorbed somehow by the rock/marine pure/maxpect spheres?

 

[Aquajan]

Here is a photo of the rock and glass bothom.
There is some white stuff on the glass what appeared after filling the tank.
I've brushed most of it off the glass the day after filling the tank.
It is probably on the rock to bud this hard to see/tell.
Could this be a layer of 100ppm calcium?

 

[ScottR]

I wouldn’t be concerned about this during a cycle. There are all sorts of fluctuations happening during a cycle. Just worry about the nitrogen cycle first.

 

[Aquajan]

Yea I'm not gonna dose anything in this stage and just gonna let it run as it is for another month.

But it's still strange that ca dropped at least 90 points..
I have brushed some of the white stuff away, waited till the water was 100% clear and meshured ca 3 hours later with no diffrance so that can't be it..
Unless that ca can't be mixed up with the water again..


When I'm adding fish can I correct the Alk and ca with the red sea foundation?

Or is this gonna create a inbalance? (as there is also strontium and barium in it)

Getting the calcium up to 450 with wc would be a pain

 

[ScottR]

Yea I'm not gonna dose anything in this stage and just gonna let it run as it is for another month.

But it's still strange that ca dropped at least 90 points..
I have brushed some of the white stuff away, waited till the water was 100% clear and meshured ca 3 hours later with no diffrance so that can't be it..
Unless that ca can't be mixed up with the water again..


When I'm adding fish can I correct the Alk and ca with the red sea foundation?

Or is this gonna create a inbalance? (as there is also strontium and barium in it)

Getting the calcium up to 450 with wc would be a pain

I highly recommend getting through the cycle and then start keeping track of elements and alk. It’s pointless to check them at this stage (unless you have coralline encrusted dry rock and hitchhiker inverts you want to keep healthy). And even then, it shouldn’t be a big deal. Assuming you’re using a good salt for mixing, you shouldn’t have crazy swings.

Are you testing for ammonia, nitrite and nitrate?

 

[Randy Holmes-Farley Verified Community Expert]

Thanks for the reply.

I didn't add Alk to the tank only a 10%wc over the past week.

I measured the tank water ca 4 times with 2 test sets witch are both new and Alk 5 times with 3 test sets.
I tested the container water 2 times on ca and Alk and that salt is from the same bucket as the tank.

Could it be possible that the calcium is absorbed somehow by the rock/marine pure/maxpect spheres?

No, there isn't any substantial sink for calcium that does not take up alkalinity in a ratio of about 2.8 dKH for each 18-20 ppm of calcium. So for a 100 ppm drop in calcium, alk would need to decline more than 10 dKH.

 

[Randy Holmes-Farley Verified Community Expert]

Yea I'm not gonna dose anything in this stage and just gonna let it run as it is for another month.

But it's still strange that ca dropped at least 90 points..
I have brushed some of the white stuff away, waited till the water was 100% clear and meshured ca 3 hours later with no diffrance so that can't be it..
Unless that ca can't be mixed up with the water again..


When I'm adding fish can I correct the Alk and ca with the red sea foundation?

Or is this gonna create a inbalance? (as there is also strontium and barium in it)

Getting the calcium up to 450 with wc would be a pain

It will be fine, although I can't imagine the reason they add barium. It has no known biological role in any organism anywhere.

 

[Randy Holmes-Farley Verified Community Expert]

Here is a photo of the rock and glass bothom.
There is some white stuff on the glass what appeared after filling the tank.
I've brushed most of it off the glass the day after filling the tank.
It is probably on the rock to bud this hard to see/tell.
Could this be a layer of 100ppm calcium?

Not if alk didn't drop a ton, but it certainly might be some precipitated calcium carbonate. Just not that much. Red Sea Coral pro is known for having some precipitation much of the time, and its no big deal since the values start high.

 

[Aquajan]

I highly recommend getting through the cycle and then start keeping track of elements and alk. It’s pointless to check them at this stage (unless you have coralline encrusted dry rock and hitchhiker inverts you want to keep healthy). And even then, it shouldn’t be a big deal. Assuming you’re using a good salt for mixing, you shouldn’t have crazy swings.

Are you testing for ammonia, nitrite and nitrate?

Im starting with artificial rock and media only with bacteria out of a bottle so no need to check elements for life stock.
NH4 is 0.15 to 0
No2 is 0.1 to 0.25
No3 is 10
Po4 is 0.067

 

[W1ngz]

I see one rock that has a distinct pink/purple colour to it. Is that artificial rock with artificial colouring, or is that the beginning of coraline algae?

Double check your testing procedure and follow it closely step by step. It could be a mistake.

Like above, I really wouldn't worry about dosing with a goal of correcting it during the cycle, but since you can't do much else with the tank the other worthwhile goal is to get some practice with testing and dosing. I would take the learning opportunity and get some simple dry alkalinity (baking soda would be perfect, cheap and easy) and calcium additives and start learning that part of managing a reef.

 

[Aquajan]

Well.. red sea foundation Ca+ is Ca Sr and Ba so I just assume that it's strontium and barium..

So I assume that somehow the start value of the calcium in the fresh salt water was not nearly 450ppm as it seems impossible it dropped 90 points.

Maby the 2 hours of mixing unheated and than heat it up to 25°c like red sea instructs is not the way to go.. As the wc container has been mixed for two weeks witch of 3 days heated and those parameters are good and do not drop.

I used to always mix the water for 24h without any problems but I wanted to do it by the book for a change.

My mistake for not meshured the water other than salinity

Im just gonna let it run for now and meshured every weekend to see if it drops any more.
I assume the alkalinity must be above 6.5 even when cyceling the tank?

 

[Aquajan]

I see one rock that has a distinct pink/purple colour to it. Is that artificial rock with artificial colouring, or is that the beginning of coraline algae?

Double check your testing procedure and follow it closely step by step. It could be a mistake.

Like above, I really wouldn't worry about dosing with a goal of correcting it during the cycle, but since you can't do much else with the tank the other worthwhile goal is to get some practice with testing and dosing. I would take the learning opportunity and get some simple dry alkalinity (baking soda would be perfect, cheap and easy) and calcium additives and start learning that part of managing a reef.

The color on the rock is artificial.
I checked the testing multiple times on new tank, old tank and fresh salt water and I get consistent readings.

I have stared my first tank with rscp salt and CA and Alk did not drop nearly as mutch..
I even filled the tank with RO and mixed the salt in the tank back than

It is my second tank btw so I know how to meshure, but the dosing or beter said the chemesty is still a challenge.
In my old tank I never could sustain sps coral for longer than 6 months..
But that's probably becous I did a lot of changing things like changing from balling to triton adding fuge stop wc remove fuge ad ats.
Not the best way to start I guess.
All that remains of the tank are the fish a bunch of softys and a lot of aptasia.

So this time I want to keep it simple and comid to 1 method from the start witch is the red sea ccp and stick with it.
The only thing I'm gonna do different is I'm gonna use a fuge in stead of carbon dosing.
And I do awc so it will always happen in time without a skip.