Just say NO to magnesium testing: RMM is born

[Randy Holmes-Farley]

Randy, did you see this?

Yes. That explained the precipitation event. The magnesium was reportedly low before that and would still be low.

It’s a confusing set of posts, since he said in post 99 that new salt water was measuring very low as well.

I am not sure he actually has low magnesium, but if he still wants to raise it after that caution, then I can help him do so.

If I’m misunderstanding anything, please point it out.

 

[Shawnman]

Currently my mag is at 1400,alk 8.6 and calcium at 400. After Saturday mornings precip event my mag was at 1060. I then added 300 ml red sea mag and now tested at 1400. Sat afternoon my alk tested at 9.9 and is currently 8.6. My pump emptied the bottle. No idea how much. I have since shut it off. My calc tested at 262 Saturday. I just now got it back to 400 after waiting until I got my mag back up raising calc up 50-70, ppm/day. My intention was to switch to BRS 2 part once I ran out of alk so that's where I currently sit.
Mag 1400,calc 400,alk 8.6.
Prior to this i kept alk at 9.0 steady. I was testing mag via Aqua Forest every 2 weeks and is always over 100 ppm low while calcium seems 450 within 10-20 ppm.
I water change 2 gallons in nano 26 weekly. Mag test on this is also low. I use Tropic Marin Pro typically but bought wrong box last time and is classic. This tests at approximately 1050 mag.
To sum it up, my levels are currently okay, will bring calc and alk up tomorrow and in the process to switching to BRS 2 Part. Historically however mag disappears at a much higher rate than calcium. Hope i explained this okay. Thank you sir

 

[Randy Holmes-Farley]

Currently my mag is at 1400,alk 8.6 and calcium at 400. After Saturday mornings precip event my mag was at 1060. I then added 300 ml red sea mag and now tested at 1400. Sat afternoon my alk tested at 9.9 and is currently 8.6. My pump emptied the bottle. No idea how much. I have since shut it off. My calc tested at 262 Saturday. I just now got it back to 400 after waiting until I got my mag back up raising calc up 50-70, ppm/day. My intention was to switch to BRS 2 part once I ran out of alk so that's where I currently sit.
Mag 1400,calc 400,alk 8.6.
Prior to this i kept alk at 9.0 steady. I was testing mag via Aqua Forest every 2 weeks and is always over 100 ppm low while calcium seems 450 within 10-20 ppm.
I water change 2 gallons in nano 26 weekly. Mag test on this is also low. I use Tropic Marin Pro typically but bought wrong box last time and is classic. This tests at approximately 1050 mag.
To sum it up, my levels are currently okay, will bring calc and alk up tomorrow and in the process to switching to BRS 2 Part. Historically however mag disappears at a much higher rate than calcium. Hope i explained this okay. Thank you sir

My diy 2/3 part (which BRS uses) follows RMM in the there is a fixed amount of part 3 to add independent of any magnesium ptesting. Of course you can occasionally measure it , but it will follow along just fine.

An Improved Do-it-Yourself Two-Part Calcium and Alkalinity Supplement System by Randy Holmes-Farley - Reefkeeping.com

 

[Nburg's Reef]

I feel vindicated! In 17 years, I’ve adjusted mag once and never dose it on the regular. Guess regular water changes is enough for me.

 

[JonoH]

I live the simplicity of this, i am auto dosing your 2 part recipe, and confused about when and how often to add Magnesium.

I could set it up on an auto doser with this method right, and just dose as you recommend % of the others?

 

[Randy Holmes-Farley]

I live the simplicity of this, i am auto dosing your 2 part recipe, and confused about when and how often to add Magnesium.

I could set it up on an auto doser with this method right, and just dose as you recommend % of the others?

Yes. The recipe involves adding 610 mL of part 3 for every gallon of calcium dosed.

 

[Miami Reef]

I love the RMM method.

I dose equal parts of my 3 part system to maintain my alkalinity.

Sodium hydroxide for alk
Calcium chloride for calcium
Balling Part C for minor, major, and magnesium

Done. I never test magnesium and I HARDLY ever test calcium. They are automatically kept in line.

I do occasional water changes, which brings the chance of my magnesium and calcium falling out of line a big fat ZERO.

 

[JonoH]

Yes. The recipe involves adding 610 mL of part 3 for every gallon of calcium dosed.

Awesome! Thanks - i thought it was that simple!

 

[FishTruck]

So… if I use a calcium reactor, which probably has Mg in the media… and my Ca and Alk test results are on target - then, I don’t need to fret about not really knowing how much Mg is getting added by the reactor media. Correct?

Maybe get an ICP test once a year?

 

[Randy Holmes-Farley]

So… if I use a calcium reactor, which probably has Mg in the media… and my Ca and Alk test results are on target - then, I don’t need to fret about not really knowing how much Mg is getting added by the reactor media. Correct?

Maybe get an ICP test once a year?

Assuming good media, yes. Especially if you also do water changes, any Mg depletion will be slow and can just be checked infrequently.

But some media may be deficient in Mg. Folks using such media sometimes add some dolomite tot eh reactor to make up for it, but that's hard to gauge properly.

 

[marinesnow]

This is gold. Thank you, Randy!

 

[Mr.Ed]

Glad I found this thread. I have never tested Mag in the 7 years i've owned a reef tank, but was so close to pulling the trigger and ordering a Mag test kit today. I guess i'll continue doing what i'm currently doing as it's been working for me (and not have to worry about chasing another set of numbers).

 

[boacvh]

I guess I have sort of always implemented RMM, based on some of your old posts so it's great it now has a name. I've haven't tested for it or dosed it in years. Sure my apex shows some number but I have never done anything about it. Since I do regular water changes I always assumed that would take care of it.

 

[doubleshot00]

Discard

 

[hllb]

I almost never test my mag. Recently, my chaeto growth has slowed down and some of the coralline one my back wall has flaked off. All my corals are growing fine - great even. Tested my mag tonight and Hanna said 1745. It’s always been high, but never that high. I assume it’s wrong, but THAT wrong?

Mixed reef tank. I use HW Marinemix reefer and change about 10% every week. I auto dose Red Sea alk and calcium and manually dose Red Sea colors once a week. I don’t dose mag specifically.

Should I just ignore this mag reading and look elsewhere for the reason my chaeto growth slowed?

 

[Randy Holmes-Farley]

I almost never test my mag. Recently, my chaeto growth has slowed down and some of the coralline one my back wall has flaked off. All my corals are growing fine - great even. Tested my mag tonight and Hanna said 1745. It’s always been high, but never that high. I assume it’s wrong, but THAT wrong?

Mixed reef tank. I use HW Marinemix reefer and change about 10% every week. I auto dose Red Sea alk and calcium and manually dose Red Sea colors once a week. I don’t dose mag specifically.

Should I just ignore this mag reading and look elsewhere for the reason my chaeto growth slowed?

It would take a massive dose to get that high (or a bad batch of salt).
Are you dosing it?

 

[hllb]

It would take a massive dose to get that high (or a bad batch of salt).
Are you dosing it?

No, not dosing it, so I assume this is just a poor test.

 

[Randy Holmes-Farley]

No, not dosing it, so I assume this is just a poor test.

Seems likely.

 

[reef’r]

Here’s my scenario… New tank with two small frags. After initial water test that I would say was probably pretty inaccurate due to never using Salifert before my mag reading has been constant between 1100-1200 through the last 3-5 water test and after getting average Mg reading of all test, even the initial which I’m sure was inaccurate, I was at 1206ppm. I’m totally for not testing mag, my alk as of last test was 10.2 and calc was 430 but mag was 1100. Should I dose mag to up it to the 1250-1300 range while I finish out the rest of the reef crystals salt or just follow RMM and forget about it

 

[Randy Holmes-Farley]

Here’s my scenario… New tank with two small frags. After initial water test that I would say was probably pretty inaccurate due to never using Salifert before my mag reading has been constant between 1100-1200 through the last 3-5 water test and after getting average Mg reading of all test, even the initial which I’m sure was inaccurate, I was at 1206ppm. I’m totally for not testing mag, my alk as of last test was 10.2 and calc was 430 but mag was 1100. Should I dose mag to up it to the 1250-1300 range while I finish out the rest of the reef crystals salt or just follow RMM and forget about it

What salt mix are you using and at what salinity? What does the kit say on that new salt water?