Why is my alkalinity going up? From what?

sanzz18 · Jul 11, 2021

So my alkalinity has been creeping up a bit over the last couple months. Tank is about 7 months old. I do not dose alkalinity or calcium, do not need to yet. I used Tropic Marin Pro Reef. A few months back my alkalinity was hanging out in the low 7s. Today it is 9.8. These are obtained by a Hannah Alkalinity checker. I haven't even been doing consistent water changes lately either because I was battling low nutrients/dinos a few months back (resolved).

I cannot begin to think of a reason why it keep creeping up. I want to keep it around 8-8.5.

Randy Holmes-Farley · Jul 12, 2021

Is nitrate declining or are you dosing it? (that adds alk)

Are you using artificial rack that may not be fully cured?

Are you topping off with tap water?

sanzz18 · Jul 12, 2021

Nitrate has stayed the same at around 8-10. The last time I dosed nitrates was over 3-4 months ago when I was fighting dinos.

All my rock I used was marco dry rock.

I have a 5 stage RODI unit, so no tap water top offs.

Randy Holmes-Farley · Jul 12, 2021

It might be the marco rock, test error, or an additive that you do not know contains alkalinity.

In any case, I'd do regular water changes with a lower alk mix (you can drop the alk in a salt mix as low as you want) to keep it from going up, if it continues.

sanzz18 · Jul 23, 2021

Randy Holmes-Farley said:
It might be the marco rock, test error, or an additive that you do not know contains alkalinity.

In any case, I'd do regular water changes with a lower alk mix (you can drop the alk in a salt mix as low as you want) to keep it from going up, if it continues.

Sorry to respond to your post so late. My new level last night was 10.1. I do not add any additives at the moment.

The salt I use is Tropic Marin Pro Reef. I tested the new saltwater batch and it was 7.0. I have been doing daily AWCs with my dos which equates to 10% weekly. I also tested my RODI water for alkalinity and got a reading of 0.1. So i checked my TDS output on my 5 stage and it says 1, so I got to change some filters. I do not necessarily believe that is the cause because the last time I checked it was 0, but who knows.

I am at a loss on how to proceed forward, especially with the strong desire to start adding SPS as my coraline is starting to take off.

BoriReefer · Jul 23, 2021

I experienced the same issue when i set up my current tank. I also run the same salt mix and was not adding/dosing anything. From what I read and gathered, it was from the dry/uncured rock I started the system with.

Grey Guy · Jul 23, 2021

Randy Holmes-Farley said:
It might be the marco rock, test error, or an additive that you do not know contains alkalinity.

In any case, I'd do regular water changes with a lower alk mix (you can drop the alk in a salt mix as low as you want) to keep it from going up, if it continues.

Are you saying there are ways to lower perimeters in an existing salt mix or just to use a different one. In other words, how would I lower the alkalinity in a commercial salt mix. It sounds awesome. If that is the case, please explain.

Nick Steele · Jul 23, 2021

sanzz18 said:
So my alkalinity has been creeping up a bit over the last couple months. Tank is about 7 months old. I do not dose alkalinity or calcium, do not need to yet. I used Tropic Marin Pro Reef. A few months back my alkalinity was hanging out in the low 7s. Today it is 9.8. These are obtained by a Hannah Alkalinity checker. I haven't even been doing consistent water changes lately either because I was battling low nutrients/dinos a few months back (resolved).

I cannot begin to think of a reason why it keep creeping up. I want to keep it around 8-8.5.

I experienced this with a different brand of salt. I had a bad batch of salt and every water change was a different alk. I never noticed this as at the time I didn’t test new salt water. I believe it slowly over time got bond up in my sand bed and possibly rocks. I switched salts and did a rip clean on my tank (also to help with Dino’s) I got rid of my sand and went bare bottom and never had an issue again.

So check that your sand isn’t hardened at all.