Alkalinity issues in old tank

MugiwaraGrape · Sep 15, 2023

Hello,

I'm having some issues with my 150g. My Alkalinity is reading in the 20s but my pH is 8.2. I've tried both red sea titration and a colorimeter and both showing in the 20s. All other levels are fine. Calcium is 450 range. I did a 30% and let it settle for a few hours. Tested again and same readings. Any help is appreciated. Thanks for reading!

T-J · Sep 15, 2023

Have you tested a fresh batch of saltwater?

MugiwaraGrape · Sep 15, 2023

T-J said:
Have you tested a fresh batch of saltwater?

Yep and it came out good.

T-J · Sep 15, 2023

MugiwaraGrape said:
Yep and it came out good.

What is "good"??

MugiwaraGrape · Sep 15, 2023

Good is alkalinity not being anywhere near what the tank is. Haha

Alkalinity was 9, pH 8.2, and calcium was ~450.

Icryhard · Sep 15, 2023

MugiwaraGrape said:
Good is alkalinity not being anywhere near what the tank is. Haha

Alkalinity was 9, pH 8.2, and calcium was ~450.

Your alk is in its 20s? Are you dosing anything ?

WhatCouldGoWrong71 · Sep 15, 2023

Take the water to a LFS or a friend and have it tested. Do you have an episode of "Dosers gone wild" going on?

MugiwaraGrape · Sep 15, 2023

WhatCouldGoWrong71 said:
Take the water to a LFS or a friend and have it tested. Do you have an episode of "Dosers gone wild" going on?

No dosing happening which is what is weird. I did however add new coral to the tank recently, but I imagine that wouldn't knock alk up that high.

MugiwaraGrape · Sep 15, 2023

Icryhard said:
Your alk is in its 20s? Are you dosing anything ?

Yeah it was around 21 a few hours AFTER a water change. I can only imagine what it was before which is even more alarming.

MugiwaraGrape · Sep 15, 2023

For more clarity on numbers and testing:

The titration red sea test was about 1.8mL which was which brought in about 20 dKH.

The Hanna Colorimeter was flashing 300 (above range) which 300 is its max and also equal to 20dKH.

Used both tests on a barrel of saltwater I had prepared for a waterchange and got my more normal numbers.

Only thing I can think to do is give it 24 hours. Do the tests again and do another 30% change. It really is such a strange thing as this tank is around 10 years old and never had such an issue. The worst that every happens is I get a pH dip and bring it right back with slow dose of sodium bicarb.

Icryhard · Sep 15, 2023

MugiwaraGrape said:
For more clarity on numbers and testing:

The titration red sea test was about 1.8mL which was which brought in about 20 dKH.

The Hanna Colorimeter was flashing 300 (above range) which 300 is its max and also equal to 20dKH.

Used both tests on a barrel of saltwater I had prepared for a waterchange and got my more normal numbers.

Only thing I can think to do is give it 24 hours. Do the tests again and do another 30% change. It really is such a strange thing as this tank is around 10 years old and never had such an issue. The worst that every happens is I get a pH dip and bring it right back with slow dose of sodium bicarb.

Your pH will recover. Do not dose anything that could bring up your alk again.

MugiwaraGrape · Sep 15, 2023

Icryhard said:
Your pH will recover. Do not dose anything that could bring up your alk again.

Really? I've always been told baking soda is perfectly fine to use in small doses. The more you know. Haha

EricR · Sep 15, 2023

Not sure if I read this correctly and don't want to jump to any conclusions but will say the following:
It's not completely unheard of for people to experience increasing alkalinity with no dosing.
*I'm having that issue in 2 year old tank that started maybe 2 months ago so, just for control, I'm doing frequent, small water changes with <0.1 dKH new saltwater (using Sodium Bisulfate mixed into new saltwater)

If you find out that may be your situation, below are a couple of threads that may be of interest:

Alkalinity Rising

Sodium Bisulfate to Reduce Alkalinity

MugiwaraGrape · Sep 15, 2023

EricR said:
Not sure if I read this correctly and don't want to jump to any conclusions but will say the following:
It's not completely unheard of for people to experience increasing alkalinity with no dosing.
*I'm having that issue in 2 year old tank that started maybe 2 months ago so, just for control, I'm doing frequent, small water changes with <0.1 dKH new saltwater (using Sodium Bisulfate mixed into new saltwater)

If you find out that may be your situation, below are a couple of threads that may be of interest:

Alkalinity Rising

Sodium Bisulfate to Reduce Alkalinity

Interesting reads for sure. Thank you for these.

Icryhard · Sep 15, 2023

MugiwaraGrape said:
Really? I've always been told baking soda is perfectly fine to use in small doses. The more you know. Haha

Yes. The problem here is that you're using baking soda, which also elevates your alk. Just make sure the surface aggitation is enough and there is enough O2 to replace the N. This will bump up your pH and it won't be fluctuating that much. For example: Let's say you need to up your alk (and just your alk) then you can use baking soda.

MugiwaraGrape · Sep 15, 2023

I haven't dosed baking soda in about 2 months now so I don't think it is that. This weird alk rise is extremely random. Nothing has been added to the tank in months except new coral a couple weeks ago. To add I also test my water weekly.

Icryhard · Sep 16, 2023

MugiwaraGrape said:
I haven't dosed baking soda in about 2 months now so I don't think it is that. This weird alk rise is extremely random. Nothing has been added to the tank in months except new coral a couple weeks ago. To add I also test my water weekly.

If you have added 0 there can be no reason for the alk to go up. What kind of water do you use?

MugiwaraGrape · Sep 16, 2023

Icryhard said:
If you have added 0 there can be no reason for the alk to go up. What kind of water do you use?

Yeah that's why this is so weird...

RO/DI which was tested both straight and a new made salt bucket like mentioned earlier. Whatever is happening is indeed happening either in the DT or sump. Even if for some reason this had been from a dose of baking soda there is no way other than dumping several cups of baking soda in to get this level of alkalinity with stable pH and calcium.

After doing some of my own reading, artificial live rock can apparently cause an all spike and a mushroom had come in attached on a fairly large rock, so wondering if maybe that can be the culprit.

Icryhard · Sep 16, 2023

MugiwaraGrape said:
Yeah that's why this is so weird...

RO/DI which was tested both straight and a new made salt bucket like mentioned earlier. Whatever is happening is indeed happening either in the DT or sump. Even if for some reason this had been from a dose of baking soda there is no way other than dumping several cups of baking soda in to get this level of alkalinity with stable pH and calcium.

After doing some of my own reading, artificial live rock can apparently cause an all spike and a mushroom had come in attached on a fairly large rock, so wondering if maybe that can be the culprit.

If you can, you could remove the rock and observe the alk during a period of time.

EricR · Sep 16, 2023

MugiwaraGrape said:
Yeah that's why this is so weird...

RO/DI which was tested both straight and a new made salt bucket like mentioned earlier. Whatever is happening is indeed happening either in the DT or sump. Even if for some reason this had been from a dose of baking soda there is no way other than dumping several cups of baking soda in to get this level of alkalinity with stable pH and calcium.

After doing some of my own reading, artificial live rock can apparently cause an all spike and a mushroom had come in attached on a fairly large rock, so wondering if maybe that can be the culprit.

Sorry,,, but I'm ridiculously confused here:

Are you using baking soda as an additive? If so,,, uhhh,,, that will obviously increase alkalinity.
*I think I mis-read that you weren't dosing anything so probably assumed wrongly that you weren't purposely adding anything that would increase alk