I have a 90 gal. 17 month old reef tank with a sump and refugium. I have mostly softies, a clam and an anemone. once a month after the water change I test for ph, ammonia, nitrate, phosphate,calcium alk, and salinity. In my fuge I have a dsb, live rock and 4 mangrove plants. I just read somewhere that mangroves suck up alot of magnesium. I have never tested for magnesium. Infact, I can't even find a magnesium test kit anywhere in my area. so before I order one online, my question is, do I really need a magnesium test kit? or do my monthly water changes replace the magnesium that my mangroves use up?

i found that over time, waterchanges just cannot replace all the minerals and elements depleted by the inhabitants' needs. don't forget that magnesium is also required to metabolize calcium. i held off for years from buying the more complicated or expensive test kits thinking that my lfs was just trying to sell me more stuff. when i finally bought more kits, i was surprised how off some of my requirements were. remember a waterchange can only replace the magnesium for only the amount of water you replaced.

If you are having problems maintaining Calcium and Alkalinity, then you may be having an issue with Magnesium levels, and may want to start to test and dose for it. If your Calcium and Alkalinity are OK, then testing and dosing Magnesium isnt a very important priority. This is advice I got from Randy, the chemistry guru on RC.

One other sign that you may have low Magnesium levels is if you are seeing alot of calcium carbonate deposits on surfaces like your heaters (abioitc precipitation).

I would definitely test for Magnesium - Salifert has good test kits!

I find that my Mg2+ levels drop over time and need to be replenished every so often.

I would definitely test for Magnesium - Salifert has good test kits!

I find that my Mg2+ levels drop over time and need to be replenished every so often.
i agree 100%. if you can afford it, buy the kit. test kits are nothing to pinch pennies on. would you rather your doctor use a thermometer, or think of possible reasons why you may or may not have a fever?

so what is that benefits of testing/treating magnesium?

so what is that benefits of testing/treating magnesium?

close to the thread anyways.
http://www.talkingreef.com/forums/showthread.php?t=1052&highlight=magnesium

u should find the treating answers in this thread, sorry about the ping pong

oh ok its in general lol thanks man :)