What role does alk/ mag/ and cal play in a tank?

World Wide Corals

mdb_talon

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The really basic answer is major components that Stony corals(as well as some algae, inverts, etc) need to grow. Alkalinity also acts as a buffer that both raises and stabilizes PH. In freshwater for examples African cichlids you add an alkalinity buffer also to increase pH and create "hard" water.

Obviously there is a lot more to it but that's what I would consider a basic answer to why we care about them in saltwater tank
 
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Peli45

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The really basic answer is major components that Stony corals(as well as some algae, inverts, etc) need to grow. Alkalinity also acts as a buffer that both raises and stabilizes PH. In freshwater for examples African cichlids you add an alkalinity buffer also to increase pH and create "hard" water.

Obviously there is a lot more to it but that's what I would consider a basic answer to why we care about them in saltwater tank
Do you have a good post I could read on ant this?
 
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mdb_talon

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flyingscampi

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The salt contains the correct level of elements, but just about everything in a reef tank uses them up. If you want to avoid large and frequent water changes, you'll need to supplement these elements. I use a product called 'All-For-Reef' by Tropic Marin which is simple to use but expensive for bigger aquariums.

Another of Randy's articles:

Lou from Tropic Marin explains their products:
 

bobnicaragua

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Starting off, do your water changes. The only thing you need to test is alkalinity, depending on what corals you are keeping. If water changes alone are not enough to maintain your alkalinity, dose kalkwasser, 2 part, or all for reef.
 
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GoVols

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Been doing a TON of research and read a horror story thread of someone not knowing, dont want this to be me. (The thread) Coming from the freshwater side so I understand cycling, but never heard of these parameters.
Kinda look at it this way:
For coral skeletal growth they need to intake cal and alk ions as separate elements


Without or low mag those two ions will bind together precipitate out and make the bound up cal and alk ions useless. Which will stop your corals from growing.

So in laymen terms, one benefit at holding mag at the right parameters is it acts like a lubricant between your alk and cal ions.
 

PatW

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Marine inverts tend to make their hard body parts from Calcium Carbonate aka limestone.

So Calcium and Alkalinity combine to produce Calcium Carbonate.

And Magnesium does substitute for Calcium somewhat. I think Calcium makes up 95% and Magnesium 5%.

But Calcium and Alkalinity can combine and precipitate out. Having Mg in the tank prevents this and that is the main role for Mg.

Another thing is that seawater contains far more Calcium than ALK. It is not that hard to have enough coral consumption of ALK to decrease the ALK by a DKH per day. Also, a change in ALK has an adverse effect on corals. A change in Calcium does not seem to bother them that much.

Once you get corals making much Calcium Carbonate, you need to dose both ALK and Calcium. But keeping ALK stable is pretty critical which makes dosers really helpful.
 

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