Alk keeps testing low 5.7 to 6.3

CaptClay

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I have had the same issue since the beginning original post is here : https://www.reef2reef.com/threads/new-tank-cycle-finished-—-trying-to-figure-out-what’s-eating-my-alk.1154168/

Tank is a Waterbox 110.4 with live sand, base rock.

Equipment: Protein skimmer with CO2 scrubber attached, UV.

Fish: Sailfin, Foxface, 2 clowns, 3 Cardinals, Goby

Corals: RBTA, Branching Hammer, 3 different types ZOA’s (not happy), Blastos, 4 Acros and encrusting monti Jedi Mind trick (looks amazing)

Salt used is Red Sea Pro. (I mix it for an hour when doing water changes)

Sump light runs at night with chaeto.

My pH peaks around 8.2 during the day and drops to 7.8 by morning

Salinity Refractometer: 1.026

Test results with Salifert Kit less than a month old:
• 09/11 6.1 DKH Cal 360 Mag 1155

• 09/16 5.7 DKH Cal 345 Mag 1155

Thought I had a salinity problem, so I had my local shop calibrate my refractometer. My fluid is 6 months old and shows 1.030 vice the 1.026 it should show.

So what could be using up all my alkalinity this fast? And is there anything else I can do to stabilize everything?
 
Last edited:
What test kit are you using?
 
It’s normal for corals to use alk and calcium as they grow and it needs to be replaced. So you will have to settle on one of the many types of dosing regimens to do that along with regular testing to keep it in check.

I personally use tropic Marin all for reef in one of my systems, and the hybrid brs tropic Marin balling method in my other. But plenty of other types work just as well once you figure them out
 
had a similar question with red sea pro; looks like the dKh of 8 on the bucket requires that you mix to 36 ppt acc to the back, whichd be about 1.027-1.028

as a sanity check id recommend testing the alk before adding it to your tank
 
It’s normal for corals to use alk and calcium as they grow and it needs to be replaced. So you will have to settle on one of the many types of dosing regimens to do that along with regular testing to keep it in check.

I personally use tropic Marin all for reef in one of my systems, and the hybrid brs tropic Marin balling method in my other. But plenty of other types work just as well once you figure them out
Yes i agree and understand, But nothing is big enough to use this much. Years back i had a 180 full of SPS and didn't loss my elements this fast.
 
had a similar question with red sea pro; looks like the dKh of 8 on the bucket requires that you mix to 36 ppt acc to the back, whichd be about 1.027-1.028

as a sanity check id recommend testing the alk before adding it to your tank
I haven't heard about the higher salinity before. This salt seems very needy, might need to go back to the old fathful instant ocean.
The ALK kit is new, I ordered it because I thought my other test kit could have been bad. (New MG and CAL)
 
The calcium and magnesium are low too. It might be worth bringing a sample to your LFS. If all 3 are low it sounds like your salt could be deficient, but it could just be that the salinity reading is off and more salt would fix the problem.
 
The calcium and magnesium are low too. It might be worth bringing a sample to your LFS. If all 3 are low it sounds like your salt could be deficient, but it could just be that the salinity reading is off and more salt would fix the problem.
Thanks. I thought about this, just to confirm. Everything keeps pointing to the salt. Its the only constant
 
Thanks. I thought about this, just to confirm. Everything keeps pointing to the salt. Its the only constant
Triple check your refractometer. Don't use distilled water, RODI water or even store bought calibration fluid to calibrate the device. Use the instructions in this article to make your own 35 ppt standard solution out of ordinary table salt and a decent kitchen scale or measuring spoons:
https://www.reef2reef.com/ams/reef-aquarium-salinity-diy-calibration-standards.956/
 
So what could be using up all my alkalinity this fast? And is there anything else I can do to stabilize everything?

I cannot tell that alkalinity is being used fast. Even if the test could distinguish 5.7 from 6.1 dKH, using less than 0.1 dKH per day is not fast.

Many things deplete it, such as accumulating nitrate or abiotic precipitation of calcium carbonate. Both could explain your values. New dry rock is very prone to getting precipitated calcium carbonate on it, especially with a high alk mix.

Unless the salinity is low, I doubt the magneisum is accurate and I no longer recommend testing it for dosing purposes since it is too often inaccurate. You cannot have consumed it down tot aht level unless you added a ton of alk and calcium that you did not mention.
 
I cannot tell that alkalinity is being used fast. Even if the test could distinguish 5.7 from 6.1 dKH, using less than 0.1 dKH per day is not fast.

Many things deplete it, such as accumulating nitrate or abiotic precipitation of calcium carbonate. Both could explain your values. New dry rock is very prone to getting precipitated calcium carbonate on it, especially with a high alk mix.

Unless the salinity is low, I doubt the magneisum is accurate and I no longer recommend testing it for dosing purposes since it is too often inaccurate. You cannot have consumed it down tot aht level unless you added a ton of alk and calcium that you did not mention.
The base rock is the same since day one (End of Feb 26).
I haven't dosed anything since last we spoke when you said stop. Only water changes.
 
The base rock is the same since day one (End of Feb 26).
I haven't dosed anything since last we spoke when you said stop. Only water changes.

I’d dose alk (baking soda) up to your preferred level.
 
Itd be the safest to tes the alk of some water you just mixed up to be sure as well as the params the bucket claims before any major changes to your tank or salt source. a 1 gallon mix should be enough to check if your salt is throwing you off; since you have ro water, if you have the time, you can also just mix some RO water and a known quantity of soda ash and see if the dkh matches what you expect as a control to see if your test is good; same for the other test kits if youve got the time
 
Itd be the safest to tes the alk of some water you just mixed up to be sure as well as the params the bucket claims before any major changes to your tank or salt source. a 1 gallon mix should be enough to check if your salt is throwing you off; since you have ro water, if you have the time, you can also just mix some RO water and a known quantity of soda ash and see if the dkh matches what you expect as a control to see if your test is good; same for the other test kits if youve got the time
I mix a gallon of new sea water using the red sea pro salt.
36ppm 12.1 DKH went a little high at first
35ppm 11.8 DKH
 
Do you have a plan on how you intend to add calcium and alkalinity going forward?
I have baking soda to bring up the ALK. Did a half dose this morning and will test again most likely tomorrow.
I also have MAG and CAL to does also. But before I do that i want to see where my ALK is tommorow when I re test.
Unless you think I should do something else?
I'm due for a water change end of this week.
 
Have not gotten around to reading all the posts. I’m willing to just say bad test kits. Had this take place for me. And I dose by what the test kits were showing. Big boo-boo!

Lost three torches, and many heads off multi head torches. All my other corals were just super ticked. Decided to get two brands of standard calibration solutions. Boy were the test kits off and by the exact number almost that my tank was showing it was off by.

When I see just discrepancies, I rather pay $40 for new test kits vs dosing. And possibly killing corals that I have thousands of dollars in.

Careful with testing and look into getting calibration solutions of various brands.

I use Fauna Marine, ATI, and Trident to check my testers now. Before I even attempted to dose.
 
I have baking soda to bring up the ALK. Did a half dose this morning and will test again most likely tomorrow.
I also have MAG and CAL to does also. But before I do that i want to see where my ALK is tommorow when I re test.
Unless you think I should do something else?
I'm due for a water change end of this week.

I would not dose magnesium. If it is low, it is only low because salinity is low. :)
 
I would not dose magnesium. If it is low, it is only low because salinity is low. :)
I think salinity is good refractometer says 35ppm and when I tested the new water at 35ppm the ALK checked out as per the salt and what DKH (11 to 12) should be at 35ppm. At least that's my analyslat and the local store checked my refractometer.
Tested the DKH about 60mins after dosing now its 6.7 will check again in the am.
 

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