coralman05
Member
What is it with ALK and KH? A good KH means a good ALK. Does it go backwards to? Need questions ask answers!
Alkalinity to KH
- Thread starter coralman05
- Start date
snakeblitz33
Well-Known Member
Alkalinity is the measurement of the resistance to the change in pH.
KH, dKH, and meq/L all measure alkalinity - but they all have different value systems.
Divide dKH by 2.8 to get ALK. Multiply ALK by 50 to get Carbonate ppt.
Here's a chart to help you find the values that you need. Typically, modern aquarists use meq/L or dKH. I see less and less people use KH or ppm CaCO3.
Alkalinity__Alkalinity____Alkalinity_____Calcium
(meq/L)____(dKH)___(ppm CaCO3)__(ppm Ca++)
--0.0---------0.0---------------------0-------------360
--0.5---------1.4--------------------25-------------370
--1.0---------2.8--------------------50-------------380
--1.5---------4.2--------------------75-------------390
--2.0---------5.6-------------------100------------400
--2.5---------7.0-------------------125------------410
--3.0---------8.4-------------------150------------420
--3.5---------9.8-------------------175------------430
--4.0--------11.2-------------------200------------440
--4.5--------12.6-------------------225------------450
--5.0--------14.0-------------------250------------460
--5.5--------15.4-------------------275------------470
--6.0--------16.8-------------------300------------480
--6.5--------18.2-------------------325------------490
--7.0--------19.6-------------------350------------500
It's best to stick to around 10dKH to 420-440ppm calcium and a magnesium reading of about 1350-1400.
Because alkalinity measures the resistence to the change in pH, a higher alkalinity typically means a more stable, higher pH value - which increases the stability of the system. Alkalinity - or carbonates and bicarbonates is what corals use to uptake calcium into their tissues to make their skeletons. So, not only do corals use calcium, but also alkalinity - so does any calcerous organism in the ocean.
Not only is alkalinity and calcium important - but without proper magnesium levels in the water column, ca and alk become unbalanced and relatively unstable. Magnesium is what helps to stabilize them - and make them "available" to use by other organisms. So, all three are important to the health of your saltwater aquarium. They all work together.
KH, dKH, and meq/L all measure alkalinity - but they all have different value systems.
Divide dKH by 2.8 to get ALK. Multiply ALK by 50 to get Carbonate ppt.
Here's a chart to help you find the values that you need. Typically, modern aquarists use meq/L or dKH. I see less and less people use KH or ppm CaCO3.
Alkalinity__Alkalinity____Alkalinity_____Calcium
(meq/L)____(dKH)___(ppm CaCO3)__(ppm Ca++)
--0.0---------0.0---------------------0-------------360
--0.5---------1.4--------------------25-------------370
--1.0---------2.8--------------------50-------------380
--1.5---------4.2--------------------75-------------390
--2.0---------5.6-------------------100------------400
--2.5---------7.0-------------------125------------410
--3.0---------8.4-------------------150------------420
--3.5---------9.8-------------------175------------430
--4.0--------11.2-------------------200------------440
--4.5--------12.6-------------------225------------450
--5.0--------14.0-------------------250------------460
--5.5--------15.4-------------------275------------470
--6.0--------16.8-------------------300------------480
--6.5--------18.2-------------------325------------490
--7.0--------19.6-------------------350------------500
It's best to stick to around 10dKH to 420-440ppm calcium and a magnesium reading of about 1350-1400.
Because alkalinity measures the resistence to the change in pH, a higher alkalinity typically means a more stable, higher pH value - which increases the stability of the system. Alkalinity - or carbonates and bicarbonates is what corals use to uptake calcium into their tissues to make their skeletons. So, not only do corals use calcium, but also alkalinity - so does any calcerous organism in the ocean.
Not only is alkalinity and calcium important - but without proper magnesium levels in the water column, ca and alk become unbalanced and relatively unstable. Magnesium is what helps to stabilize them - and make them "available" to use by other organisms. So, all three are important to the health of your saltwater aquarium. They all work together.
bang guy
Moderator
Just to refine what Snake said (which I agree with) true KH can be significantly different than Alkalinity and there are times when you want to know what the KH is. KH is a measure of Carbonate and Bicarbonate. Normally this is pretty close to Alkalinity (resistance to change in PH) but Alkalinity is not only made up of Carbonate. Borate and a few other compounds can contribute to Alkalinity.
The reason there could be a significant difference is if you use a PH buffer (Alkalinity additive) that has a high level of Borate such as some of the Seachem products the Carbonate (KH) level could be low or even zero. The reason you would want to know the KH level is because corals use mostly Carbonate to build skeleton and if the Borate concentration is too high and Carbonate low then they cannot grow even though Alkalinity would test high.
The reason there could be a significant difference is if you use a PH buffer (Alkalinity additive) that has a high level of Borate such as some of the Seachem products the Carbonate (KH) level could be low or even zero. The reason you would want to know the KH level is because corals use mostly Carbonate to build skeleton and if the Borate concentration is too high and Carbonate low then they cannot grow even though Alkalinity would test high.