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View Full Version : Magnesium spike experiences



mkengr45
Fri, 26th Dec 2014, 01:32 PM
First off, everything in the tank looks absolutely perfect...just a little ****ed about my mg levels.

All tests were done using Salifert test kits and backed up with Hanna meters (where applicable) or GHL sensors where applicable


Alk 7.9 (Hanna meter)
pH 8.32 (GHL probe and handheld probe)
Cal 485 (Hanna meter and Salifert)
Mg 2000 (Salifert)
Temp 78.7 (GHL probe)
Salinity 1.026 (GHL probe and PinPoint handheld probe)

I pretty much have every probe and test kit that is out there...

I'm concerned about the high mg. I dose two part and use kalkwasser in my top-off tank and have done so for about 13 years. I use Aquavitro Salinity salt and do 30 gallons per week water change. Tank is SPS dominant 144g half circle. I recently added a refugium with 30# of sand and some mangroves and chaeto. I don't see any ill effects on the corals but am a little irritated at the high mg. I usually run higher alkalinity (9ish) so I increased my GHL doser by 9ml per day on the alk and Ca channels. I never even dose magnesium since the Salinity salt used in my water changes keeps mg in check.

Honestly I rarely even check mg as everything has been stable for years...all I check is alk and Ca periodically and I mostly just look at certain corals and can tell when I need to up the dosers.

Does anyone thing that adding a new refugium with 30# of sand might have made the Mg jump up in the tank?

I'm leaning towards a bad test kit...it's a year or two old.

mkengr45
Fri, 26th Dec 2014, 10:24 PM
Thanks for all the input (sarcastically)!

I figured it out... Apparently there are several versions of instructions for Salifert Mg test kits...I'm guessing it depends on when your particular kit was released. So if you lose your original instructions and can't recall from memory how to do it you can't solely rely on the various PDFs posted online.

Some versions say use 3ml of water and others say 2ml and both have different amounts of the first reagent, both say one spoon of #2 but depending on your kit the dam spoon is slightly different volume, and they all have the same last step.

Anyhow, just passing this along.

My Mg turned out to be 1350

Dkray944
Sat, 27th Dec 2014, 01:13 AM
Nice looking clam! I'm glad you figured it out. I was going to say maybe bad batch of salt before I read your second post.

mkengr45
Sat, 27th Dec 2014, 08:08 AM
Nice looking clam! I'm glad you figured it out. I was going to say maybe bad batch of salt before I read your second post.

Hey thanks! The clam is really cool however at ~15" across it sure does take up a lot of space.

Randy