Alkalinity is rising and I can't understand why

[Dj City]

How is your ATO working - is it compensating well for evaporation ? Has your salinity risen lately ? I also notice from your OP you dont specify where the Alk was before your rising problem started - how much has it risen ?

My ATO is working fine. No problems there.
Salinity has actually lowered but i'm using the Neptune salinity probe and that is prone to changes with water temp and whatever else makes it fluctuate.

My alk is usually about 8.2 - 8.7Dkh. It has been at about that level for over a year. Cal usually sits around 450ppm.
Ph usually sits at about 8.

 

[Dj City]

Corals still look fine but I read that they usually respond slowly to alk spikes.
What is a range that is considered a spike?
Is what i'm experiencing considered a spike? If so, how bad of a spike is it?

Most importantly, What is the cause and how do I correct this?

 

[RuuToo]

How is your ATO working - is it compensating well for evaporation ? Has your salinity risen lately ? I also notice from your OP you dont specify where the Alk was before your rising problem started - how much has it risen ?

Ive found that an auto top off failure tends to boost magnesium rather than calcium or alk in this kind of setup (trident controlled dosing). I noticed that my mag levels had been increasing for a few days, and it turned out I had unplugged my ato and forgotten about it. My calcium and alk levels remained stable thanks to their more rapid consumption and my dosing keeping up, but magnesium (and salinity, but the apex salinity probe is so twitchy I tend to ignore it) kept rising

 

[Dj City]

I'm not using the Trident controlled dosing.
My ATO is working fine and keeping my water level topped up.

 

[Deep]

Ive found that an auto top off failure tends to boost magnesium rather than calcium or alk in this kind of setup (trident controlled dosing). I noticed that my mag levels had been increasing for a few days, and it turned out I had unplugged my ato and forgotten about it. My calcium and alk levels remained stable thanks to their more rapid consumption and my dosing keeping up, but magnesium (and salinity, but the apex salinity probe is so twitchy I tend to ignore it) kept rising

Assuming consumption remains the same, evaporation will increase all levels including Alk, Ca etc. I am not very familiar with trident controlled dosing, but I am assuming if Alk reads higher the dosing will reduce due to controlled dosing ?
So unless your consumption increased proportionately just during those days when your ATO failed, all levels should increase, not just mag.

 

[RuuToo]

I'm not using the Trident controlled dosing.
My ATO is working fine and keeping my water level topped up.

Apologies, but I was mostly agreeing with you I think :). Just sharing my experience that mag tends to be the thing that increases noticeably for me with an auto top off failure, not necessarily alk. Out of interest, what is your mag looking like?

 

[RuuToo]

Assuming consumption remains the same, evaporation will increase all levels including Alk, Ca etc. I am not very familiar with trident controlled dosing, but I am assuming if Alk reads higher the dosing will reduce due to controlled dosing ?
So unless your consumption increased proportionately just during those days when your ATO failed, all levels should increase, not just mag.

yeah. That’s not what is happening in this situation, but when the Neptune is controlling dosing and no top off occurs the alk and calcium will remain stable since they are consumed fast and dosing is reduced but mag will keep increasing as salinity does

 

[Dj City]

Before starting the Trident calibration, mag was at 1398.

When the calibration has completed, I will run another test to see where things stand.

 

[Dj City]

Calibration is complete.
Trident reads the same as on the calibration solution which is...
Alk 8.25
Cal 405
Mag 1235
I am now testing the reef.
Once complete, I will post the results.

 

[Dj City]

After calibration...

Alk 9.25
cal 466
Mag 1410
Ph 7.9
salt 34.9
Temp 78.1

Neptune Dos is OFF.
I'm not dosing until levels even out.

I considered doing a water change or two but I don't know what's going on and I don't want to make matters worse by changing things without knowing what's going on.

Anyone have any idea what might be going on?

 

[Randy Holmes-Farley Verified Community Expert]

I'd keep watching the alk and track it with no dosing. I suspect the ongoing rise (if any) will be quite slow) and what you are mostly detecting is a slowdown in calcification by the aquarium for some reason.

 

[Dj City]

I'd keep watching the alk and track it with no dosing. I suspect the ongoing rise (if any) will be quite slow) and what you are mostly detecting is a slowdown in calcification by the aquarium for some reason.

That's the only thing I can think of.
I wonder if the prazipro may have something to do with what's going on?

 

[Dkmoo]

Is your CO2 concentration increasing? I think more dissolved co2 will convert to bicarbonate and increase alk but that'll be couplebwith a decrease in pH?

 

[Dj City]

So...
I removed the 5 micron filter sock and put the Clarisea SK 5000 filter roller back on.
At 6am this morning while the 5 micron filter sock was in place, my alk tested at 8.95.
I put the filter roller back on and retested.
At 10am with the filter roller, my Alk tested at 8.7

Right now....

Alk 8.7
Cal 457
mag 1415
Ph 7.91
No3 5
P04 0.16

I don't know how a filter sock could alter or raise Alk or Cal but it kinda looks like that's what happened.

Any ideas?