Alk up to 16, but corals are doing fine, should I just leave it?

Tayreef93 · Sep 4, 2023

My tank is a 20 gallon and its about 15 months old. My alk is 16, ph 8.4-8.5, calcium around 460, mag 1500. Nitrate is 6, and phos is .3. Im working on getting the phos down with water changes and brightwell phos e. Im just wondering because most people keep there alk around 8-10. But mines never hone below 12, i dose kalk to maintain high ph and water evap. Im wondering since my corals dont seem bothered by my alk being on the extreme side of high. If I wanted to add new corals what would be the best way to acclimate them? Thanks for any suggestions!

Spare time · Sep 4, 2023

Eh id just leave it.

Tuan’s Reef · Sep 4, 2023

Is kalk the only thing you dose? What salt mix? RODI water?

what test kits used? 16 is pretty high

Stevorino · Sep 4, 2023

I'd triple check the alk is really that high before doing anything. I can't tell you how many decisions I've made over the years because of a bad test kit (or two).

I personally wouldn't keep a tank that high... whenever my alk has gotten higher than ~10 it just feels like corals are in fast-forward mode, making them more sensitive to everything, both good and bad. But that's just my experience.

If you decide to make an adjustment, I'd just do it slowly over the course of weeks by slowing down kalk and/or water changes.

Tayreef93 · Sep 4, 2023

Tuan’s Reef said:
Is kalk the only thing you dose? What salt mix? RODI water?

what test kits used? 16 is pretty high

Ya thats all i dose, i use mainly hanna checkers for alk, phos, nitrate, and ph. Red sea for calcium, and aqua forest for mag. I use brightwell neomarine salt, ro water. It was 16 yesterday and today is 14.1, weird how it dropped. It goes up about 1 dkh per day till i do my weekly water change

Tayreef93 · Sep 4, 2023

Stevorino said:
I'd triple check the alk is really that high before doing anything. I can't tell you how many decisions I've made over the years because of a bad test kit (or two).

I personally wouldn't keep a tank that high... whenever my alk has gotten higher than ~10 it just feels like corals are in fast-forward mode, making them more sensitive to everything, both good and bad. But that's just my experience.

If you decide to make an adjustment, I'd just do it slowly over the course of weeks by slowing down kalk and/or water changes.

Ya its not consistently that high, it fluctuates between 12-16 over the past year. Ive tried turning the kalk down or off and surprisingly the corals respond badly. Im just wondering because ive been told not to chase numbers and to just leave things alone if your corals are fine. But everyone else keeps it less than 12. But maybe my tank is just different idk!

Tuan’s Reef · Sep 4, 2023

The Hanna Alk gives false readings when the bottle gets low. I use salifert for Alk as it’s cheaper and more consistent

Lavey29 · Sep 4, 2023

I'm guessing bad test results. Get second opinion.

Tayreef93 · Sep 4, 2023

Its a fresh bottle, i back checked it with my red sea alk kit and its the correct number, i think my alk is just high

Tayreef93 · Sep 4, 2023

Lavey29 said:
I'm guessing bad test results. Get second opinion.

It’s been consistently going up and I checked it with my red sea kit and it says the same thing,

Lavey29 · Sep 4, 2023

Tayreef93 said:
Its a fresh bottle, i back checked it with my red sea alk kit and its the correct number, i think my alk is just high

With your low nutrients levels and that high of alk your corals should be toast but hey every tank is unique. I'd still have my LFS run your numbers.

o2manyfish · Sep 4, 2023

What kind of corals do you have, how big and how many?

If you have a bunch of Softies and Slow growing SPS then you're adding kalkwasser for pH and alkalinity but there is nothing consuming the alkalinity. Pointless to add something if your system isn't using it.

You haven't given enough information to give you an answer to help you decide which direction you should go if any.

Dave B

dschuffert · Sep 4, 2023

As others have said, I would validate that the reading is really that high. If so, and the corals are doing well, I would leave it and let it fall naturally a little over time.

Stevorino · Sep 5, 2023

Tayreef93 said:
Ya thats all i dose, i use mainly hanna checkers for alk, phos, nitrate, and ph. Red sea for calcium, and aqua forest for mag. I use brightwell neomarine salt, ro water. It was 16 yesterday and today is 14.1, weird how it dropped. It goes up about 1 dkh per day till i do my weekly water change

Just my 2 cents, but I would try to decrease kalk to the point where it's not increasing daily but staying in the same ballpark day over day. This reads as if you are overdosing kalk and then the water changes bring it back down to planet earth.

While the corals may be surviving in this environment, but they could be doing even better with more stability.

Whatever you do or don't do, I would just go slowly. Sudden changes, like turning off kalk altogether, is almost always more damaging than a parameter that creeps over time.