Relationship with Cal and Alk

dcforester1 · 05/22/2012, 09:51 PM

Every time I read an article explaining the relationship between them I get more confused. I have a hard time getting my Alk above 8 in my current tank, and I am wondering if because of that i should keep my calcium at a certain level? I currently have my cal at 460. When I had my old tank my alk was at 9 and my cal was at 460 and everything seemed much happier. i was wondering if my calcium should be lower now that my alk is? If you are confused now you know how I feel.

TIA for any and all responses. Derek

bertoni · 05/22/2012, 10:06 PM

460 ppm is fine. As long as calcium doesn't get too high, it has zero effect on the alkalinity level. "Too high" means something more like 800 ppm and up, most likely, but each tank varies a bit in that respect.

Many tanks consume 2-3 dKH per day, and require daily dosing of some sort to keep the alkalinity level up. This article might help pick a way to get going:

http://reefkeeping.com/issues/2007-05/rhf/index.php

Getting a 2-part, like B-Ionic, is a very simple first step you could try. That can get expensive over time, depending on the size of the tank, but it'd give you some time to research your options carefully.

Randy Holmes-Farley · 05/23/2012, 04:50 AM

What are you dosing that is having trouble?

Bear in mind that, as Jonathan mentions, reef tanks can use a lot of calcium and alkalinity supplements and most often need them every day.

dcforester1 · 05/25/2012, 06:38 PM

Thanks guys, I have had a reef tank for about four years, and about three of them with a calcium reactor. About 9 mos ago I upgraded from a 75, to a 120, and my tank hasn't looked as good since. In my 75 I kept the alk a little higher, but with this new tank I am having a hard time keeping it up that high. Thats why I was wondering if I keep the alk lower in this tank does the calcium need to be lower as well.

I didn't know if you were starting a a tank and wanted your alk to be at 9, should your calcium be at X? or will things do as well in a tank where alk is 7, and cal is 480, or alk is at 10 and cal is at 400.

I don't know if I am confusing you, but sorry if I am.

TIA Derek

bertoni · 05/25/2012, 09:04 PM

Ah, I see. You might need a larger reactor, if you don't want to dose a 2-part or the like.

As long as the alkalinity stays in the 7-11 dKH range and the calcium is in the 350-500 ppm range, the tank should be fine. Some people have come up with various equations to "match" the two parameters, but the equations are meaningless.

05/22/2012, 09:51 PM	#1
dcforester1 Registered Member Join Date: May 2009 Location: Boston Posts: 259	Relationship with Cal and Alk Every time I read an article explaining the relationship between them I get more confused. I have a hard time getting my Alk above 8 in my current tank, and I am wondering if because of that i should keep my calcium at a certain level? I currently have my cal at 460. When I had my old tank my alk was at 9 and my cal was at 460 and everything seemed much happier. i was wondering if my calcium should be lower now that my alk is? If you are confused now you know how I feel. TIA for any and all responses. Derek

05/22/2012, 10:06 PM	#2
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 68,459	460 ppm is fine. As long as calcium doesn't get too high, it has zero effect on the alkalinity level. "Too high" means something more like 800 ppm and up, most likely, but each tank varies a bit in that respect. Many tanks consume 2-3 dKH per day, and require daily dosing of some sort to keep the alkalinity level up. This article might help pick a way to get going: http://reefkeeping.com/issues/2007-05/rhf/index.php Getting a 2-part, like B-Ionic, is a very simple first step you could try. That can get expensive over time, depending on the size of the tank, but it'd give you some time to research your options carefully. __________________ Jonathan Bertoni

05/23/2012, 04:50 AM	#3
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 81,937	What are you dosing that is having trouble? Bear in mind that, as Jonathan mentions, reef tanks can use a lot of calcium and alkalinity supplements and most often need them every day. __________________ Randy Holmes-Farley Club 65535 Current Tank Info: 120 mixed reef

05/25/2012, 09:04 PM	#5
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 68,459	Ah, I see. You might need a larger reactor, if you don't want to dose a 2-part or the like. As long as the alkalinity stays in the 7-11 dKH range and the calcium is in the 350-500 ppm range, the tank should be fine. Some people have come up with various equations to "match" the two parameters, but the equations are meaningless. __________________ Jonathan Bertoni

05/25/2012, 06:38 PM	#4
dcforester1 Registered Member Join Date: May 2009 Location: Boston Posts: 259	Thanks guys, I have had a reef tank for about four years, and about three of them with a calcium reactor. About 9 mos ago I upgraded from a 75, to a 120, and my tank hasn't looked as good since. In my 75 I kept the alk a little higher, but with this new tank I am having a hard time keeping it up that high. Thats why I was wondering if I keep the alk lower in this tank does the calcium need to be lower as well. I didn't know if you were starting a a tank and wanted your alk to be at 9, should your calcium be at X? or will things do as well in a tank where alk is 7, and cal is 480, or alk is at 10 and cal is at 400. I don't know if I am confusing you, but sorry if I am. TIA Derek