Alk concerns

[Aveadonat]

I've had my tank running for roughly a month and the alkalinity has always been subpar, and I've noticed it decrease over time. No corals, just clownfish, and I'm not sure if they consume alkalinity, but when I first started the tank my alk was roughly 140 ppm (7.8 dKH) and now over the past 3 days I've measured its been sitting around 120-126 ppm (6.7-7 dKH).

The weird part is my pH has been completely fine, and it's been sitting at 8-8.1 since the tank was set up. I use the Hanna alkalinity colorimeter to check for alk, and for pH, I've been using the Hanna HALO. I'm going to test pH and alk tonight, as well as test the saltwater I have from my LFS which is what I use in the tank.

I haven't done a water change yet and it's probably the main culprit, so I plan on doing one this weekend. However, if my alk levels are still low after the water change, should I consider dosing with ash soda or anything else that would bring my alk up?

 

[ptrusk]

Accumulating nitrate depletes alkalinity. Water change will probably be fine.

 

[Aveadonat]

Accumulating nitrate depletes alkalinity.

Using hanna LR nitrate test kit the most amount of nitrate I've seen is 2.1, and I also have an API stick test kit that's been showing less than 25 nitrates. The API test kit likely could be inaccurate, but as for the hanna one, I have a lot of trust in its accuracy.

 

[Aveadonat]

When I text pH/Alk tonight I’ll also test nitrate and phosphate

 

[ptrusk]

Double check salinity also.

 

[Aveadonat]

Double check salinity also.

Will do. It’s been at 1.025 using a refractometer but I haven’t calibrated it in a month, should I recalibrate?

 

[Aveadonat]

Just checked alk, salinity, pH, and the basic nitrate test

Alk 128 ppm
Salinity 1.025
pH 8.1
Nitrates <20

I’m going to do phosphate and the digital nitrate test tomorrow since i’m tired lol, and i’ll also test my LFS’ alk tomorrow and send those numbers.

 

[ptrusk]

Those levels are fine for fish. Yeah alk is a little on the low side but regular water changes should handle that for now. Not really an issue with no coral. Water changes will also lower your nitrate which again isn’t too bad but keep an eye on it.

You never said what size tank or if you use a skimmer.

 

[Aveadonat]

Those levels are fine for fish. Yeah alk is a little on the low side but regular water changes should handle that for now. Not really an issue with no coral. Water changes will also lower your nitrate which again isn’t too bad but keep an eye on it.

You never said what size tank or if you use a skimmer.

20 Cube, I have a miniq bubble magus nano skimmer. I plan on adding corals eventually so if I don't see an increase in alk levels from water changes I might dose the ash soda, or something equivalent.

 

[EeyoreIsMySpiritAnimal]

I've had my tank running for roughly a month and the alkalinity has always been subpar, and I've noticed it decrease over time. No corals, just clownfish, and I'm not sure if they consume alkalinity, but when I first started the tank my alk was roughly 140 ppm (7.8 dKH) and now over the past 3 days I've measured its been sitting around 120-126 ppm (6.7-7 dKH).

The weird part is my pH has been completely fine, and it's been sitting at 8-8.1 since the tank was set up. I use the Hanna alkalinity colorimeter to check for alk, and for pH, I've been using the Hanna HALO. I'm going to test pH and alk tonight, as well as test the saltwater I have from my LFS which is what I use in the tank.

I haven't done a water change yet and it's probably the main culprit, so I plan on doing one this weekend. However, if my alk levels are still low after the water change, should I consider dosing with ash soda or anything else that would bring my alk up?

Your tank is only a month old! It is still very unstable and, while you've established a nitrifying bacterial colony capable of keeping up with the bioload (aka "cycled the tank"), the system will go through many other cycles before it reaches its "normal" state.

Yes, do regular water changes. Do not start dosing alk (or anything else) until your water changes can't replenish what is used... And aside from any shelled animals, nothing in the tank is consuming a significant amount of calcium, magnesium, or alkalinity.

Please go to the main page of this ("New to saltwater...") forum and read some of the sticky threads. They will help you a lot

Good luck and welcome to the hobby!

 

[EeyoreIsMySpiritAnimal]

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[EeyoreIsMySpiritAnimal]

*Find out what salt mix your LFS uses, and ask if they always use the same kind for the saltwater they sell. Different salts have different levels of various elements and you want to be sure you know what you're putting in your tank. It might even be best (and cheaper) for you to buy your own salt and mix your water at home... that way you know it's consistent. If you have the space, filtering your own water with an RODI will also pay off in the long run.