alk consumption..

[J Rog]

So I have been keeping my alk between 8-8.5dhk by doing a 10 gallon water change once a week (on a 70 gallon tank) and dosing 2 part via doser (Neptune DOS) 4ml equal parts of alk and CA. But all of a sudden I caught my alk dropping to 6.5 3 or 4 days ago. So I upped the dosage to 6ml of both Alk and CA. And have been adding extra alk by hand hand. First night I dosed an extra 10ml of alk. The next day the alk level dropped to 6dhk. So I added another 15ml extra alk on top of the daily dose of 6ml. That got it back to 6.5 DHK. So over the course of a couple of days I have been trying to get it back to 8dhk. But my main question here is it normal for a tank to all of a sudden uptake a lot of alk? I haven’t added a bunch of new coral all at once or anything like that..

 

[Coronus]

Are you running gfo?

 

[Aaron-A2]

Do you have a lot of coralline algae? The amount of alk it consumes can be significant.

 

[J Rog]

Are you running gfo?

Nope

 

[J Rog]

Do you have a lot of coralline algae? The amount of alk it consumes can be significant.

Yes, my tank is 9 months old and over the past 2 or 3 months the coralline has really taken off.

 

[Coronus]

So to me it appears that you need to test alk daily for a few days to know what your daily consumption rate is. Use the BRS Calculator to set up daily dosing. Sounds like your consumption is higher than your dosage.
Bring it inline with what you want it to be. Then dose accordingly. I dont believe coraline algae will not effect it that much. JME

 

[Aaron-A2]

So to me it appears that you need to test alk daily for a few days to know what your daily consumption rate is. Use the BRS Calculator to set up daily dosing. Sounds like your consumption is higher than your dosage.
Bring it inline with what you want it to be. Then dose accordingly. I dont believe coraline algae will not effect it that much. JME

Good to know. Question! How much alk do you dose per day? I'm guessing something like (1) 55 gallon brutes worth

 

[FugeTown]

Just out of curiosity what is your Magnesium at?

 

[Coronus]

I currently only dose 132 ml a day of alk and 132 ml of cal in my big tank. I recently removed about 10 large acropora colonies for my DT so it dropped from 193.
I keep my magnesium at 1350-1400.

 

[Randy Holmes-Farley Verified Community Expert]

Bring it inline with what you want it to be. Then dose accordingly. I dont believe coraline algae will not effect it that much. JME

Coralline algae uses a lot of calcium and alk and is the biggest user in many tanks with mostly soft corals.

 

[Coronus]

Coralline algae uses a lot of calcium and alk and is the biggest user in many tanks with mostly soft corals.

Right! My systems are all acroporas. I scrape all coraline weekly off the back glass. It def grows, but maybe a few spots a week. My consumption comes from coral growth.

 

[J Rog]

Thanks guys! I’m working on bringing it where I want it.

 

[Martin Kuhn]

Maybe your tanks biology has simply improved resulting in better coral growth.
Maybe you reached a better nutrient level than before and or have better light/spectrum than before. Also stability of the values helps a lot as corals get used to.

As a result corals grow better, demanding for more Ca / Alk.

Should be a good sign and requires elevated 2 part dosing amounts.