Average Mag dosing by aquarium size?

[FishTrader]

I assure you I searched for an hour before starting this thread; is there a table of average alk/cal/mag dosing per tank size in reef keeping? I know every tank is different, but I'd like to think there's ballpark numbers for lets say, mixed reef 65 gal there's an average dose of ___, ___, and ___.

 

[Randy Holmes-Farley Verified Community Expert]

I assure you I searched for an hour before starting this thread; is there a table of average alk/cal/mag dosing per tank size in reef keeping? I know every tank is different, but I'd like to think there's ballpark numbers for lets say, mixed reef 65 gal there's an average dose of ___, ___, and ___.

Typical reef tanks consume 0.3 to 3 dKH per day of alk, and a commensurate amount of calcium (2-20 ppm) and magnesium (0-2 ppm) per day.

 

[FishTrader]

Typical reef tanks consume 0.3 to 3 dKH per day of alk, and a commensurate amount of calcium (2-20 ppm) and magnesium (0-2 ppm) per day.

Thanks. My tank has about 6 SPS frags, few LPS and decent amount of macro algae and seems like 40ml of mag daily in a 65g keeps it steady but seemed like a lot.

 

[Dburr1014]

40ml of mag daily??
Something not right.

 

[Randy Holmes-Farley Verified Community Expert]

Thanks. My tank has about 6 SPS frags, few LPS and decent amount of macro algae and seems like 40ml of mag daily in a 65g keeps it steady but seemed like a lot.

What else are you dosing?

 

[FishTrader]

What else are you dosing?

I have 2 part Ionic that I use 30ml every Wednesday manually to keep me at 8.5dkh and 410cal. I perform 10gal water changes every saturday. I added Fluval Magnesium 40ml every other day last week bc my Salifert test kept the results at 1260ish and 2 days without it registered 1210. I misspoke about every day.

 

[Randy Holmes-Farley Verified Community Expert]

I have 2 part Ionic that I use 30ml every Wednesday manually to keep me at 8.5dkh and 410cal. I perform 10gal water changes every saturday. I added Fluval Magnesium 40ml every other day last week bc my Salifert test kept the results at 1260ish and 2 days without it registered 1210. I misspoke about every day.

What brand of two part? How much of the alk part every day?

I'd stop using the Fluval. It's not the best formulation, and I cannot find a potency for it so it may be doing almost nothing useful.

I'm skeptical that you have substantial excess magnesium demand.

 

[FishTrader]

What brand of two part? How much of the alk part every day?

I'd stop using the Fluval. It's not the best formulation, and I cannot find a potency for it so it may be doing almost nothing useful.

I'm skeptical that you have substantial excess magnesium demand.

Thanks! I'm migrating to an Aquaforest line of supplies anyways so I'll use it till the good stuff arrives

 

[GatorGreg]

Thanks. My tank has about 6 SPS frags, few LPS and decent amount of macro algae and seems like 40ml of mag daily in a 65g keeps it steady but seemed like a lot.

That’s is hardly anything livestock wise. I absolutely can’t believe that your 10g weekly water change isn’t keeping up with your demand currently. Do you have a whole bunch of coraline?

how old is your tank?

you sure you’re not making testing errors?

 

[gbroadbridge]

Thanks! I'm migrating to an Aquaforest line of supplies anyways so I'll use it till the good stuff arrives

Honestly, Mg drops so slowly in most tanks you can almost not worry about it.

In my 75 gal tank I dose the equivalent of about 300ml of Aquaforest Components Pro 1,2 3 every day and check my Mg about every 2 months. If it's dropped by 80-120ppm, I add sufficient Mg over a couple of days to bump it back up to around 1300-1350.

 

[FishTrader]

That’s is hardly anything livestock wise. I absolutely can’t believe that your 10g weekly water change isn’t keeping up with your demand currently. Do you have a whole bunch of coraline?

how old is your tank?

you sure you’re not making testing errors?

I am using a salifert test and am METICULOUS. I added a decent amount of red macroalgae to the display and I thought that might be it bc I've never done that before. I think based on the responses here I'm going to circle back after my new mg arrives.
Tank is 5 months old.
Salt is currently IO Reef Crystals but it's leaving this weird brown residue and I ordered AF Reef Salt too

 

[Randy Holmes-Farley Verified Community Expert]

Bear in mind that small changes in salinity can impact magnesium measurements. A drop in salinity from sg = 1.026 to sg = 1.025 will drop magnesium from 1300 ppm to 250 ppm, even though no magnesium was consumed.

 

[FishTrader]

Bear in mind that small changes in salinity can impact magnesium measurements. A drop in salinity from sg = 1.026 to sg = 1.025 will drop magnesium from 1300 ppm to 250 ppm, even though no magnesium was consumed.

I found this chart another reefer posted and the dropoff is the month after he added macro algae. I'm thinking this could be it.

 

[Randy Holmes-Farley Verified Community Expert]

I found this chart another reefer posted and the dropoff is the month after he added macro algae. I'm thinking this could be it.

Not sure what you are suggesting, but no macroalgae takes up large amounts of magnesium, and those rare ones that do calcify (such as Halimeda) take up far more calcium and a boatload of alk.

 

[FishTrader]

Not sure what you are suggesting, but no macroalgae takes up large amounts of magnesium, and those rare ones that do calcify (such as Halimeda) take up far more calcium and a boatload of alk.

OK, so new data indicates my salinity is 4 to 5 points below common. I dont know for fact bc coral from 3 different retailers arrived this week and before dipping regiment i decided to test the salinity. 1.029, 1.031,1.030
MY LEVEL 1.025. Its worth noting that I have not only kept my corals alive this far, they are growing too!
After getting a new refractometer I will post more