Just say NO to magnesium testing: RMM is born

[Shawnman]

Or your salinity is incorrect

Could be, but I test with a calibrated refractometer.

 

[Garf]

Could be, but I test with a calibrated refractometer.

Calibration fluid @ 35ppt, or RODI? Does your alkalinity and/or calcium come out at whatever it's supposed to?

Edit - just noticed your using Tropic Marin classic. I use the classic and on the rare occasion I've tested new salt water, mag, calcium and alkalinity is spot on.

 

[Shawnman]

Calibration fluid @ 35ppt, or RODI? Does your alkalinity and/or calcium come out at whatever it's supposed to?

I use 35 pt calibration fluid. My alk and cal both seem to test correctly. I was dosing 10 - 20 ppm calc bout the same for alk, but mag would consistently be off 150 ppm

 

[Shawnman]

My tank was using way way more mag than anything else in my tank. I ve since stopped testing and adding 10% mag to my calcium consumption and my tank is looking great. ‍

 

[thatmanMIKEson]

if magnesium is off a little bit (150mg/l +/-) try using the RMM test kit...

using the RMM proprietary kit, test magnesium 5 to 10 times, then with all the different values you WILL get, average them all together then this will be within 200ppm +/- of your actual magnesium level.

don't forget even the RMM kit has an allowable range of accuracy and acceptability.

 

[Shawnman]

if magnesium is off a little bit (150mg/l +/-) try using the RMM test kit...

using the RMM proprietary kit, test magnesium 5 to 10 times, then with all the different values you WILL get, average them all together then this will be within 200ppm +/- of your actual magnesium level.

don't forget even the RMM kit has an allowable range of accuracy and acceptability.

Rite.... Lol

 

[Shawnman]

Not testing my mag resulted in my magnesium dropping to 1062, that then resulted with my calcium precipitating and dropping to 262. I had calcium carbonate /snow throughout my tank. My magnesium test was correct all along matching with what the lfs reported. Not saying that the above method is wrong but it didn't work out for me and I will be going back to testing for mag and dosing appropriately. My animals are largely unaffected and I am getting my levels back to where they need to be but apparently my tank uses way more than 10% of the calcium used.

 

[Randy Holmes-Farley]

Not testing my mag resulted in my magnesium dropping to 1062, that then resulted with my calcium precipitating and dropping to 262. I had calcium carbonate /snow throughout my tank. My magnesium test was correct all along matching with what the lfs reported. Not saying that the above method is wrong but it didn't work out for me and I will be going back to testing for mag and dosing appropriately. My animals are largely unaffected and I am getting my levels back to where they need to be but apparently my tank uses way more than 10% of the calcium used.

I do not mean to be excessively harsh, but I simply do not believe that what you are saying is true. What you write is chemically impossible if you were truly following RMM.

Contrary to popular mantra, not all tanks are different. Chemistry is unchanged from tank to tank, and things that are not possible are not possible in every tank.

I'm not saying that you necessarily made up what you post, but there are many other interpretations of what you observed, and continued test error is by far the most likely.

Ignoring magnesium (say, assume you had zero in the tank), to drop calcium from 420 ppm to 260 ppm will NECESSARILY consume 22.4 dKH of alk. No other possibility exists. Where would that even come from to allow the precipitation event you suggest? If it happened, a big overdose of alkalinity would be required, and is the typical cause of such events, not lack of magnesium,.

In any case, it is worth trying to understand RMM, not just saying it did not work for you. If you following each of the three steps in post 1, neither calcium nor magnesium will become depleted as you suggest. The method is not to just stop testing, it involves adding an appropriate amount of calcium and magnesium.

 

[thrillreefer]

Uh oh, Big Watertest is NOT going to like the new RMM… but the rest of us will! I’m onboard

 

[Shawnman]

not really sure what could have crashed your major elements that dramatically. Did something change in you’re tank any time before this?

The thing is your mag is what’s going to keep your ca and alk balanced. If you try and start adding calcium with a mag below 1250 you will probably see your dkh drop dramatically.

If you are sps heavy then maybe add 10pm mag every 12 hours, but if mostly lps or softies you should be fine with a 40ppm per day rise. My main display is mostly lps and I’ve raised my mag by 40ppm over 24 hours with no issues. If you want to be cautious, try raising the mag by 20ppm on the first day, see if there’s any issues 24 hours later, and if everything looks fine, go up to 30 or 40ppm per day.

Not sure what the size of your tank is, but, personally what I would do is a 20% water change every other day directly followed by adding an additional 20ppm magnesium directly after the water change. I would do this for 3 times in a row (every other day until you hit the third water change), then test your levels again.

I do not mean to be excessively harsh, but I simply do not believe that what you are saying is true. What you write is chemically impossible if you were truly following RMM.

Contrary to popular mantra, not all tanks are different. Chemistry is unchanged from tank to tank, and things that are not possible are not possible in every tank.

I'm not saying that you necessarily made up what you post, but there are many other interpretations of what you observed, and continued test error is by far the most likely.

Ignoring magnesium (say, assume you had zero in the tank), to drop calcium from 420 ppm to 260 ppm will NECESSARILY consume 22.4 dKH of alk. No other possibility exists. Where would that even come from to allow the precipitation event you suggest? If it happened, a big overdose of alkalinity would be required, and is the typical cause of such events, not lack of magnesium,.

In any case, it is worth trying to understand RMM, not just saying it did not work for you. If you following each of the three steps in post 1, neither calcium nor magnesium will become depleted as you suggest. The method is not to just stop testing, it involves adding an appropriate amount of calcium and magnesium.

You're not harsh at all. We're adults here. I'm a tool maker /handyman and don't pretend to understand reef chemistry. I do the best i can to enjoy my hobby.
I had a pump that somehow dumped my alkalinity bottle into the tank. No idea how much. I woke up to a white coating covering everything. Upon investigation I found out what happened. My alk only tested at 9.9. I have an aio and a lot of it ended up in the back. I tested all my levels and my lfs retested with their $1200 fancy machine and they confirmed all the tests were pretty accurate and identical to each other. Whenever I tested my mag, I assumed it was wrong and instead of dosing 120 ml of mag solution i would only add 1 ml mag because my calc consumption was only 10 ppm.
Obviously my pump failure was the root cause of this precipitation event but I should have verified the inaccuracy of my mag test. My testing results still indicate that my tank consumes more mag than calcium according to the way I am testing and interpreting things. The RMM method may be great and i hate testing mag but the way I was practicing it didn't work out for me regardless of the alk pump failure.

 

[RSNJReef]

Ok, that makes a lot more sense, and if your mag had been low to begin with, the spike in all would have caused your Cal to crash.

As a side note, your calcium and mag consumption can go down at different rates overall depending on your salt and water change frequency. I personally have a 90 gallon filled with over 15 torch colonies and over 7 different montipora species, and both of those love mag. I do a 30% water change weekly with reef crystals and I have not had to add calcium for over 4 months, while my mag I need to up it by 20-30 ppm every 2 weeks.

 

[Shawnman]

Ok, that makes a lot more sense, and if your mag had been low to begin with, the spike in all would have caused your Cal to crash.

As a side note, your calcium and mag consumption can go down at different rates overall depending on your salt and water change frequency. I personally have a 90 gallon filled with over 15 torch colonies and over 7 different montipora species, and both of those love mag. I do a 30% water change weekly with reef crystals and I have not had to add calcium for over 4 months, while my mag I need to up it by 20-30 ppm every 2 weeks.

I guess this is my point. If you were to quit testing mag and only add 5 - 10% mag based on your calc consumption, it sounds like your magnesium levels would also become dangerously low unless I am completely missing the whole thing entirely.
I do perform a 10 water change religiously every week on my 26 gallon red sea nano. I'm not really trying to discredit the rmm method, as it sounds fantastic in theory, just not sure if it applies 100% to every reef tank out there.

 

[smitten with ocean life]

Absolutely.

They are best kept on a shelf next to pet rocks.

 

[Randy Holmes-Farley]

I guess this is my point. If you were to quit testing mag and only add 5 - 10% mag based on your calc consumption, it sounds like your magnesium levels would also become dangerously low unless I am completely missing the whole thing entirely.
I do perform a 10 water change religiously every week on my 26 gallon red sea nano. I'm not really trying to discredit the rmm method, as it sounds fantastic in theory, just not sure if it applies 100% to every reef tank out there.

It applies in 100% of reef aquaria. There are no deviations where magnesium is consumed more than about 1/10th of the calcium consumption. How could it be? Where would it go?

Any "examples" where it does not are test error, water changes with extra low magnesium, or salinity changes, not real consumption.

 

[Shawnman]

It applies in 100% of reef aquaria. There are no deviations where magnesium is consumed more than about 1/10th of the calcium consumption. How could it be? Where would it go?

Any "examples" where it does not are test error, water changes with extra low magnesium, or salinity changes, not real consumption.

It applies in 100% of reef aquaria. There are no deviations where magnesium is consumed more than about 1/10th of the calcium consumption. How could it be? Where would it go?

Any "examples" where it does not are test error, water changes with extra low magnesium, or salinity changes, not real consumption.

Nevermind. Not to be "harsh". Not trying to cause any negativity but you clearly only see this from one perspective.

 

[Randy Holmes-Farley]

Nevermind. Not to be "harsh". Not trying to cause any negativity but you clearly only see this from one perspective.

Lol
Yes, science truth.

If you see it from some other perspective, that’s your choice.

 

[Shawnman]

Lol
Yes, science truth.

If you see it from some other perspective, that’s your choice.

If you could help me, that would be great other than saying that my test must be wrong because I have already proved to myself by 2 different sources that its not wrong. I'm not trying to argue bro.

 

[Shawnman]

If you could help me, that would be great other than saying that my test must be wrong because I have already proved to myself by 2 different sources that its not wrong. I'm not trying to argue bro.

If you could pm me directly would be helpful. Have a good day sir.

 

[Randy Holmes-Farley]

If you could pm me directly would be helpful. Have a good day sir.

I don’t do pm’s, but I’m more than happy to help.

If you are convinced magnesium is currently low, you must raise it to desirable levels before using RMM or any other method of supplementing calcium, alkalinity, and magnesium.

There are many suitable commercial and diy magnesium supplements that are suitable.

What do you have in hand and what do you believe the magnesium level currently is?

 

[Miami Reef]

I had a pump that somehow dumped my alkalinity bottle into the tank. No idea how much. I woke up to a white coating covering everything.

Randy, did you see this?