Calcium depletion

[Mttkiely]

So this may b a dumb question but I'm gunna ask anyway... I'm new to having more then one lps coral in my tank and am quickly moving towards lps dominated tank. I do a 15 gallon water change every week and my calcium is between 450 and 475 ish after the water change. Now my question is how fast do my lps corals actually suck it up after my water change? I know if I test periodically thru out the week that I will b able to get the answer that way but I'm just trying to get a ballpark answer as I've heard from many people that lps corals don't use up the elements replenished by a water change as fast as say Sps corals or even clams... Now as far as growth goes everything is growing well and I haven't seen any fluctuations in that so I'm assuming the swing in Params isn't all that much hopefully someone that has more experience with this question will b able to answer as I'm trying to figure out if I need to eventually start dosing how I'm gunna go about doing it thanks!

[Randy Holmes-Farley]

LPS generally grow slowly, and you'll notice calcification far sooner in the need for alkalinity than in the need for calcium. With LPS only, coralline algae may be the biggest user of calcium and alkalinity.

Are you monitoring alkalinity?

This has more:

The “How To” Guide to Reef Aquarium Chemistry for Beginners, Part 2: What Chemicals Must be Supplemented
http://reefkeeping.com/issues/2007-04/rhf/index.php

[Mttkiely]

Thanks for the reply! I haven't tested for it in Aswell as the others but everything looks great and is growing very well I know I should test and I think I will test starting after this water change I'm gunna do on Tuesday...

[Randy Holmes-Farley]

In a tank like yours, alkalinity is the most important one. If you do not need alkalinity (and you are not adding any) you won't need any other supplements. :)