Alkalinity question

[spawn]

Being still fairly new to the hobby, why does everyone dose alk? I recently started using two little fishies a & b and it caused an alk spike ( ^-13 ) needless to say I stopped dosing. Prior to using it my alk had never been above 9-10 dkh It's now back to 9. So I'm wondering what causes the drop in alk that people dose to counter-act. My tank is now only 5 months old, it's pretty much fully stocked with sps. Is alk consumed?

[Skimmerking]

yes alk is what usaly goes first. i had a heck of a time teying to keep my alk at 9-10 so i left it at 8 all the time.... once you get the Alk to a stable level and the Ph and Cal will all work its self out.

[kien]

calcareous organisms such as LPS and SPS corals require ALK and calcium to build their skeletons. Alk typically is consumed at a greater rate so as Mike said it typically depletes first. If your alk isn't dropping (much), that probably means you are replenishing it via water changes at a rate equal to or greater than the rate at which it is being used up by your corals. There are any number of reasons why corals will consume more or less Alk. For example, If corals are happy with ALL other parameters such as light, low nutrients, flow, etc, they may be in the mood to grow lots and thus may take up these trace elements. Some corals will grow every slowly and thus will consume Alk and calc very very slowly. Of course, the number of corals (per volume) you have in your system is a factor as well.

[untamed]

There are some things about your question that suggest to me that you should do some reading on Calcium and Alkalinity supplementation methods.

I would recommend that you start at this article and go from there.

http://www.advancedaquarist.com/issues/feb2003/chem.htm

Greatly simplified, you don't want to be adding an Alk supplement alone. Generally speaking you need to add both Ca and Alk in a balanced way. Using your A & B you were on the right track, but you likely added too much which showed itself as a high alkalinity.

[spawn]

Thanks for the link.