My system is not using ALK [?]

[Berlibee]

Hey guys,

About a week ago I've noticed my alkalinity started to rise so I stopped dosing.
I'm not doing water changes at all. So after a week with no 2 parts dosing levels are exactly the same.
Why do you think it happened, why the system could stop using ALK ... corals are very happy with good PE and colors, but slow growing. I didn't do any changes in the system.

 

[Denisk]

Check your mag

 

[chuckfu5]

I had this happen with my calcium. It turned out that my magnesium was low. Got it back in line and everything followed.

 

[Berlibee]

Thanks guys I've checked it the first thing it's 1330.

 

[madcanary]

as said check you Mag, i just had this same issue. i didn't realise how low it was untill i realised how much Mag was needed to raise it. then your alk will drop
what kit did you use to test?

 

[Denisk]

Thanks guys I've checked it the first thing it's 1330.

That’s not bad. My only thing is to maybe double check with someone else to make sure your mag test is correct.

Can you add some more details about your system such as coral stocking level, tank size, what you were dosing before, etc....

 

[Berlibee]

My Mg. is at 1350 at this moment I've checked with a new Salifert kit there is no mistake.

 

[Randy Holmes-Farley Verified Community Expert]

Low pH will reduce demand. Did you recently close windows for the season?

What is the alk and how much was it previously declining each day? The lower the alk the lower the demand.

 

[Berlibee]

That’s not bad. My only thing is to maybe double check with someone else to make sure your mag test is correct.

Can you add some more details about your system such as coral stocking level, tank size, what you were dosing before, etc....

Sure, it's a Reefer 250 with 55g NET water volume. A new system - 4 months old, stocked with only sps frags and zoas. Good stocked. It was using 0.3 per day before.

 

[Berlibee]

Alk. 8.0
Ca. 430
Mg. 1350

 

[Randy Holmes-Farley Verified Community Expert]

Alk. 8.0
Ca. 430
Mg. 1350

How much was it previously dropping?

 

[Berlibee]

Low pH will reduce demand. Did you recently close windows for the season?

What is the alk and how much was it previously declining each day? The lower the alk the lower the demand.

Minimum pH 7.8, Maximum 7.95. Average 7.86
No didn't close anything and I have CO2 monitor in the room with the tank and I open windows if the levels get too high.

 

[Berlibee]

How much was it previously dropping?

It was using 0.3 per day before.

 

[Randy Holmes-Farley Verified Community Expert]

0.3 dKH per day is not very much, but if it really has dropped, either coral calcification or abiotic precipitation has been reduced, and those most often get reduced by lower pH, alk, and calcium, and typically, higher magnesium, phosphate, and organics.

It could be a nonchemical reason too, like flow or lighting changes.

 

[Berlibee]

Ok thanks, but no ... nothing was changed.