Magnesium Dosing

edm3d

New Member
View Badges
Joined
Apr 23, 2026
Messages
23
Reaction score
4
Location
Houston
Rating - 0%
0   0   0
Hello everyone! Below are my first water parameter testing (after water change and had to wait for some salifert test kits) now that I have a bit more coral and want to make sure that I'm keeping well and happy.

Ammonia not tested
Nitrite not tested
Nitrate 5ppm (Imagitarium test kit)
Salinity ~1.0255 (between 1.025 and 1.026 via refractometer)
Phosphate undetectable (imagitarium test kit, waiting on an ULR Hannah Checker)
Magnesium ~1100ppm (Salifert)
Alk 8.6 dKH (Salifert)
Calcium 400ppm (Salifert)

I tested my fresh saltwater mix before doing a water change just to see what that tests at as well, and I got around 1100ppm for the fresh batch. Using IO Reef Crystals.

This is for a 20 gal system with about 14gals of actual water volume.

I bought ions from aquavitro to raise the magnesium haven't started Dosing yet.

My question is, does dosing magnesium have any affect on any other parameters? And how much of the solution should I be dosing per day? Lastly, why would my salt mix be lower in magnesium than what is advertised on the bucket. I use a heater and powerhead while the salt is mixing and all of this is done overnight so that the next day I can do my water change. I change 4gals every week

I had my local LFS also conduct a magnesium test to verify my results
 
Last edited:

Randy Holmes-Farley

Reef Chemist
View Badges
Joined
Sep 5, 2014
Messages
89,598
Reaction score
93,010
Location
Massachusetts, United States
Rating - 0%
0   0   0
Testing of magnesium at home is too fraught with problems to make me recommend it.

I expect the magnesium is much higher, closer to what Rac normally has at that salinity. I personally would not dose any in this scenario.

This has more:

 
OP
OP
E

edm3d

New Member
View Badges
Joined
Apr 23, 2026
Messages
23
Reaction score
4
Location
Houston
Rating - 0%
0   0   0
Testing of magnesium at home is too fraught with problems to make me recommend it.

I expect the magnesium is much higher, closer to what Rac normally has at that salinity. I personally would not dose any in this scenario.

This has more:

Forgot to mention on the post, but I had my testing verified, specifically magnesium, at an LFS store and they also concluded at 1100ppm.
 

Randy Holmes-Farley

Reef Chemist
View Badges
Joined
Sep 5, 2014
Messages
89,598
Reaction score
93,010
Location
Massachusetts, United States
Rating - 0%
0   0   0
Doesn’t convince me. Lfs testing would not be any more reliable.

That said, to answer your original question, magnesium dosing will only impact salinity, raising it. Nothing else will be impacted.
 

TOP 10 Trending Threads

HOW DO YOU ADJUST YOUR CUC AS ALGAE DISAPPEARS?

  • Capture and re-home CUC

    Votes: 10 8.4%
  • Increase white light/hours in tank to spur algae growth to feed CUC

    Votes: 8 6.7%
  • Feed nori to support CUC

    Votes: 39 32.8%
  • Feed herbivore pellets to support CUC

    Votes: 42 35.3%
  • Allow attrition to balance CUC and algae

    Votes: 51 42.9%
  • Provide macro algae to feed CUC

    Votes: 8 6.7%
  • Introduce CUC predators

    Votes: 1 0.8%
  • Other (please explain)

    Votes: 12 10.1%
Back
Top