[Pomme]

Strontium, is it needed?

I have just tested my tank water for Strontium and it was 4. I have always thought that it was good to have strontium in the tank so dosed it, i had read books which said it was a necessarl element, Dakin, N. , Hargreaves, V.

But i have just read parts of Borneman, E. , Nilsen, F., which say that it isnt proved whether it is a benefit to have it in the tank, but they both seem to dose it to there tanks but not a NSW levels of 8, but they had theres at 4.

Have recently got a calcium reactor so this should be adding to the strontium, but should i get a bottle to dose it up to the levels of 10?

Just wondering what you guys think of it and whether its needed?

[Ninong]

Even though I know of no evidence that strontium is actually required by any of the animals that we keep in our reef tanks, I don't see anything wrong with dosing it as long as you do not exceed NSW concentration. Just be sure you test for it first with a reliable and accurate test kit.

What brand of salt mix are you using? The most popular brand, Instant Ocean, has more than double the NSW concentration of strontium.

Dr. Randy Holmes-Farley has written an interesting article on strontium: http://www.advancedaquarist.com/issues/nov2003/chem.htm

[Pomme]

yeah i am using kent salt. and the test kit i am using is the salifert one which came out with 4.

[LazyReef]

I would not base wheater to does strontium on one authors opinion. Like all literature an opposing opinion always exits.

On my view... You know that your reactor provides Sr from the crushed coral. It is in the crushed coral beacuse the animal grew the skeleton with it included. Sr, Mg and Ca are all metals which are similar enough that they are intereact to form the coral skeleton in a similar fashion. It would follow that then Sr is important. It has been argued that Sr weakens coral skeletons. It has also been argured that both Sr and Mg are important in formiing the matrix of the skeleton.

Sr, Mg, and Ca are also an important part of a balanced buffer system along with carbonates. These exist in NSW in a certain ratio. This ratio is consistant throughout all NSW. Since these corals are old and have evovled slowly. SPS branching corals being most advanced it would follow IMO that this buffer system could have influenced the way in which the coral adapted over time to become most efficient at growing and reproducing.

It has also been reported that Sr helps increase the growth SPS. This may be because the Sr is the smallest number in the ration of Sr, Mg, anc Ca. It maybe the rate limiting metal in the formation of the complex matrix the coral deposits to form the skeleton. This is also the argument that supports decreased strength in a SPS do to hight Sr aditions. In other words, it may grow faster with Sr, but in will break easier.

I add it and have always added it. I use a Ca reactor too.

[Ninong]

Another view is that strontium performs no verifiable function. It is just there and because it is so similar to calcium it can interfere with the mechanism of calcium absorption in human bones or calcium deposition in coral skeletons. It is known that excessive strontium causes aberrations in human bones by interfering with calcium absorption. In much the same way excessive strontium interferes with the mechanism of calcium deposition in coral skeletons. We know that elevated levels of strontium are detrimental to bone development in mammals and we have known for about twenty years now that elevated levels of strontium are detrimental to coral growth.

Since natural seawater levels of strontium range from 8.1 - 10 ppm, it would be wise to test aquarium water for strontium concentration to make sure that it is deficient before adding it. In fact, it would be wise to test for anything before adding it, especially something like strontium or iodine that are known to cause problems at elevated levels.