Extremely low DkH on a new tank

[mercurialchen]

So I have a new tank which has been cycled for 2 weeks with one torch only, I added a rock with GSP and a rock with Zoas yesterday. Today I checked the alkalinity with Salifert test kit and the result was 4.5dkh. It was so low that I had to test again to be sure but the result was still the same. I cannot understand how the alkalinity would drop so significantly even though I have so few corals. A few days ago alk was about 8dkh. What is wrong and what should I do about it? My corals are still looking healthy and happy but Im thinking about a quick water change to bring up the alk.

Salt mix: Aquaforest sea salt, which is advertised to have 8.3-8.9dkh at 1026sg. Current salinity: 1025sg

 

[csturgis1989]

Is there any coralline algae growing? That could be taking up alk. I would say if everything looks happy not to worry too much especially with it being a new tank. Just do your regular water changes and eventually things will stabilize as the tank matures.

 

[ryanjohn1]

How many times did you test?

 

[mercurialchen]

How many times did you test?

I tested twice and the results were the same. I did have some activated carbon in the filtration though, could it be the culprit of this?

 

[mercurialchen]

Is there any coralline algae growing? That could be taking up alk. I would say if everything looks happy not to worry too much especially with it being a new tank. Just do your regular water changes and eventually things will stabilize as the tank matures.

I dont think there is coraline algae anywhere in the tank

 

[ryanjohn1]

I’ve not personally seen that.

 

[ryanjohn1]

How long has the tank been running in total. You said it was cycled for 2 weeks ?

 

[mercurialchen]

Here's how my torch looking. Right now it does not look upset to me but I read online that torches require much higher alk to thrive

 

[mercurialchen]

How long has the tank been running in total. You said it was cycled for 2 weeks ?

Yes 2 weeks. I dose aquaforest bio, bios and np pro everyday for 2 weeks. Just did a 10% water change yesterday too

 

[ryanjohn1]

So the tanks been running a total of 2 weeks?

 

[csturgis1989]

The last thing you want to be doing with a new tank is chasing alk and calcium numbers. Just do 10 to 20 percent weekly water changes with 1.025 saltwater and let your tank mature.

 

[mercurialchen]

So the tanks been running a total of 2 weeks?

Yes 2 weeks in total. Alk has been low since day 1 with AF reef salt. I switched to AF sea salt because it has higher alk.
I kept salinity stable at 1025

 

[CoachRichardson]

Was the tank setup with dry rock? The rock can be taking up the Alk. I would caution on the big water change. You don't want Alk jumping. If you do a water change do a small one, test the level and keep making small ones until you bring it back where you want it.

 

[mercurialchen]

Was the tank setup with dry rock? The rock can be taking up the Alk. I would caution on the big water change. You don't want Alk jumping. If you do a water change do a small one, test the level and keep making small ones until you bring it back where you want it.

It was. I dont have any live rock in my tank. As for water changes, I only did 10% for 3 times total

 

[ryanjohn1]

like csturgis was saying probably not gonna chase numbers yet. That’s a very young tank and you’re going to have swings. Maybe wasn’t the best idea tossing coral in this early.

 

[ryanjohn1]

10% weekly’s water changes and regular maintenance probably don’t need to test daily. You’re going to see swings. Tank probably isn’t “done” cycling

 

[Randy Holmes-Farley Verified Community Expert]

Did you use that same alk test on the new salt water? It might be test error. Which kit?

Cycling depletes alkalinity. The conversion of ammonia into nitrate depletes the alk.

 

[mercurialchen]

Did you use that same alk test on the new salt water? It might be test error. Which kit?

Cycling depletes alkalinity. The conversion of ammonia into nitrate depletes the alk.

I used the same Salifert test kit. I tested alk on the newly mixed water before it going into the tank and it showed around 8dkh

 

[Randy Holmes-Farley Verified Community Expert]

I used the same Salifert test kit. I tested alk on the newly mixed water before it going into the tank and it showed around 8dkh

Then it is likely from cycling. Just boost it back with baking soda:

Reef Chemistry Calculator

 

[mercurialchen]

Then it is likely from cycling. Just boost it back with baking soda:

Reef Chemistry Calculator

Thank you sir. I bought some baking soda and will follow the instruction in the link