Alkalinity vs dKH

MarkD40 · 03/17/2006, 10:47 AM

Bought a new Seachem alkalinity test kit. It works by the titration method. It states that it tests for "total alkalinity" "which in the marine tank should be 4-6." I keep reading that dKH sould be 8-12. I am confused. Am I testing for something different?

Travis L. Stevens · 03/17/2006, 10:50 AM

Alkalinity is a test for how much Carbonate there is. dKH and Meq/L are measurements of Alkalinity.

rustybucket145 · 03/17/2006, 01:16 PM

So an Alkalinity test doesn't really test alkalinity?

Travis L. Stevens · 03/17/2006, 01:25 PM

Pretty much. At least for the purposes of Reek Keeping. It is much easier to think of it this way without going into extreme detail. For example, we use Alkalinity test kits and Calcium test kits to make sure everything is ideal and balanced. Usually when one of these two is a little off, we have to add one or the other to get it back in line. Randy Holmes-Farley could give you the best description of it in his forum. But here is a definition of Alkalinity via Wikipedia.com - http://en.wikipedia.org/wiki/Alkalinity

MarkD40 · 03/17/2006, 03:44 PM

Thanks Travis!

Randy Holmes-Farley · 03/18/2006, 09:31 AM

Alkalinity (meq/L) and dKH are exactly the same things when measured with an aquarium test kit. They are just different units, like inches and centimeters.

1 meq/L = 2.8 dKH = 50 ppm calcium carbonate equivalents.

My recommendations are to maintain 2.5-4 meq/L = 7-11 dKH = 125-200 ppm CaCO3 equivalents

I discuss them in detail in these articles:

What is Alkalinity
http://www.advancedaquarist.com/issu.../chemistry.htm

The Units of Measure of Reefkeeping
http://reefkeeping.com/issues/2005-08/rhf/index.php

rustybucket145 · 03/18/2006, 09:02 PM

Excellent... It is all so clear now.... And it only took a Chemist from Genzyme to explain that simple analogy.

Thank you Randy.

Randy Holmes-Farley · 03/19/2006, 08:48 AM

You're welcome.

Happy Reefing.

Chaotic Reefer4u · 03/19/2006, 10:42 AM

wow randy, you sound pretty much very well edumacated, time to hit the book's...

Randy Holmes-Farley · 03/19/2006, 01:50 PM

Good luck!

03/17/2006, 10:47 AM	#1
MarkD40 Registered Member Join Date: Feb 2006 Location: Kansas Posts: 647	Alkalinity vs dKH Bought a new Seachem alkalinity test kit. It works by the titration method. It states that it tests for "total alkalinity" "which in the marine tank should be 4-6." I keep reading that dKH sould be 8-12. I am confused. Am I testing for something different?

03/17/2006, 10:50 AM	#2
Travis L. Stevens Registered Member Join Date: Nov 2004 Location: Perry, OK Posts: 13,946	Alkalinity is a test for how much Carbonate there is. dKH and Meq/L are measurements of Alkalinity. __________________ Travis Stevens Current Tank Info: Restarting 28g Bowfront

03/17/2006, 01:16 PM	#3
rustybucket145 Registered Member Join Date: Jan 2006 Location: valdosta, ga Posts: 3,707	So an Alkalinity test doesn't really test alkalinity? __________________ 400gals of various tanks in the same system. Current Tank Info: 2 175w MH, 2 VH0 Actinics, Lots of Live Rock, tons of copepods, a Fat Mandarin Goby, Niger Trigger, Yellow Tang, Falco Hawkfish, Bi-Color Pseudo, numerous soft, SPS and LPS Corals

03/17/2006, 01:25 PM	#4
Travis L. Stevens Registered Member Join Date: Nov 2004 Location: Perry, OK Posts: 13,946	Pretty much. At least for the purposes of Reek Keeping. It is much easier to think of it this way without going into extreme detail. For example, we use Alkalinity test kits and Calcium test kits to make sure everything is ideal and balanced. Usually when one of these two is a little off, we have to add one or the other to get it back in line. Randy Holmes-Farley could give you the best description of it in his forum. But here is a definition of Alkalinity via Wikipedia.com - http://en.wikipedia.org/wiki/Alkalinity __________________ Travis Stevens Current Tank Info: Restarting 28g Bowfront

03/17/2006, 03:44 PM	#5
MarkD40 Registered Member Join Date: Feb 2006 Location: Kansas Posts: 647	Thanks Travis! __________________ My ship came in. Unfortunately it hit a reef. Current Tank Info: 110 gallon reef display tank, fish, LPS, SPS and mushrooms. A 75 gallon sump in basement with protein skimmer, 40watt UV sterilizer, RO/DI, refugium with chaeto, phosban reactor. 40 gallon frag tank.

03/18/2006, 09:31 AM	#6
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	Alkalinity (meq/L) and dKH are exactly the same things when measured with an aquarium test kit. They are just different units, like inches and centimeters. 1 meq/L = 2.8 dKH = 50 ppm calcium carbonate equivalents. My recommendations are to maintain 2.5-4 meq/L = 7-11 dKH = 125-200 ppm CaCO3 equivalents I discuss them in detail in these articles: What is Alkalinity http://www.advancedaquarist.com/issu.../chemistry.htm The Units of Measure of Reefkeeping http://reefkeeping.com/issues/2005-08/rhf/index.php __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef

03/18/2006, 09:02 PM	#7
rustybucket145 Registered Member Join Date: Jan 2006 Location: valdosta, ga Posts: 3,707	Excellent... It is all so clear now.... And it only took a Chemist from Genzyme to explain that simple analogy. Thank you Randy. __________________ 400gals of various tanks in the same system. Current Tank Info: 2 175w MH, 2 VH0 Actinics, Lots of Live Rock, tons of copepods, a Fat Mandarin Goby, Niger Trigger, Yellow Tang, Falco Hawkfish, Bi-Color Pseudo, numerous soft, SPS and LPS Corals

03/19/2006, 08:48 AM	#8
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	You're welcome. Happy Reefing. __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef

03/19/2006, 10:42 AM	#9
Chaotic Reefer4u ♥Acropora Aficionado♥ Join Date: Jul 2004 Location: Hollister,Ca. Posts: 5,163	Justification for a Higher Education... wow randy, you sound pretty much very well edumacated, time to hit the book's... __________________ Live everyday as if it was your last, take time to smell the flowers, enjoy all things living, never take anything for granted, you just never know when your number might be up... Current Tank Info: * 90g. Reef Ready TruVu tank with 30g. Platinum Filtration Series Sump SpS Acro enthusiast *

03/19/2006, 01:50 PM	#10
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	Good luck! __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef