how much no3 decreasing raises alk?

[shakacuz]

i'm noticing my alk is rising. searching previous threads i've come to realize it could be:

test error
sand/rock dissolving
no3 lowering

i am testing alk with hanna checker and red sea test kit. ranges are close, but not exact. so i am ruling out test error.

how much no3 decline warrants a raise in alk?

 

[Randy Holmes-Farley Verified Community Expert]

Consumption of 50 ppm nitrate causes a 2.3 dKH (0.8 meq/L) increase
in alkalinity.

 

[shakacuz]

Consumption of 50 ppm nitrate causes a 2.3 dKH (0.8 meq/L) increase
in alkalinity.

well in that case it is not my no3 that is causing my alk to raise.. it is only lowering about 0.5-1ppm/week
sodibum bisulfate would be my next move then..

 

[Randy Holmes-Farley Verified Community Expert]

well in that case it is not my no3 that is causing my alk to raise.. it is only lowering about 0.5-1ppm/week
sodibum bisulfate would be my next move then..

Take it very slow if you add it to the tank.

 

[shakacuz]

Take it very slow if you add it to the tank.

roughly 50g water volume. how much should i start with? and for how long? how do i know when to stop?

 

[Randy Holmes-Farley Verified Community Expert]

roughly 50g water volume. how much should i start with? and for how long? how do i know when to stop?

You are going to add directly, or to drop the alk in new salt water for a water change?

 

[shakacuz]

You are going to add directly, or to drop the alk in new salt water for a water change?

directly. i don't do water changes(wish i could, actually. just too inconvenient in my living space)

lots of inverts, sps, and zoas. some lps.

 

[Randy Holmes-Farley Verified Community Expert]

Do you have a sump, and how big is it?

Do you monitor pH?

 

[Randy Holmes-Farley Verified Community Expert]

Dropping alk by 1.4 dKH will drop pH from about 8.1 to 6.9 , so that's way too much at once.

I'd drop it by 0.05 dKH at once by adding dissolved sodium bisulfate to your sump. Then track pH if you have a meter. The drop should not be more than 0.1 pH units or so.

Wait between doses for pH to rise a bit, and do it during the daytime pH peak.

Be certain of your math before dosing.

Sodium Bisulfate to Reduce Alkalinity in New Salt Water or in Display Tanks

I just want to record these calculations in their own thread to refer back to in other threads. When alkalinity is too high in new salt water or in a display tank, acid can be used to lower the alkalinity. You can easily use muriatic acid (hydrochloric acid), or sodium bifulfate (e.g...

www.reef2reef.com

 

[shakacuz]

Do you have a sump, and how big is it?

Do you monitor pH?

i do monitor pH, but i may have some test error as my hanna egg checker is reading over 8.6(blinking)

sump is a 20G long.

 

[Randy Holmes-Farley Verified Community Expert]

I'd recalibrate the Hanna.

 

[shakacuz]

I'd recalibrate the Hanna.

calibration kit arrives tomorrow. decided to go this route before purchasing a different meter/tester.. was looking at the: https://www.hannainst.com/hi98107-phep-ph-tester.html?hsLang=en