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.
 

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