Magnesium Low

ackermsb · May 10, 2021

Hi everyone-

My 32G Fluval Flex tank has been up and running for about 7 weeks with the upgraded Fluval second light, upgrade pump (sicce syncra 1.5, (2) intank media chambers, good flow with Current USA 1,000gph pumps which are barely on.

I use red sea coral salt

Stock/Coral List:
- Clowns (2)
- Possom Wrasse
- Diamond Goby - constantly stirring up the tank but filtration is solid so quickly clears
- Frogspawn
- Finger Leather
- Goni
- Zoa's
- Mushrooms

Everything in the tank seems to be doing really well.

For the last two weeks I went to my lfs and had them test my water and here is two weeks ago.

I then started dosing one cup of my lfs magnesium a day

After one week, here were my updated params:

MG was up about 100 after dosing one cup a week and performing at least on 15-20% water change.

Salinity pretty stable at around 1.024

I have increased my magnesium daily dose to a cup and a half but the problem is that I figure it would be much higher.

Any thoughts on why it remains low (as well as my PH) and recommendations for how to improve? Or, is it just a new tank so patience is required?

I did just add a phosphate remover to my filtration in the hopes of continuing to bring that down.

Also, my LFS told me not to worry about calcium or at the moment since I don't have much in the tank requiring Calcium.

As always, appreciate the help!

dwest · May 10, 2021

I would buy a salifert mg kit and verify the low value. It seems suspicious to me.

Fish Think Pink · May 10, 2021

ackermsb said:
Hi everyone-

My 32G Fluval Flex tank has been up and running for about 7 weeks with the upgraded Fluval second light, upgrade pump (sicce syncra 1.5, (2) intank media chambers, good flow with Current USA 1,000gph pumps which are barely on.

I use red sea coral salt

Stock/Coral List:
- Clowns (2)
- Possom Wrasse
- Diamond Goby - constantly stirring up the tank but filtration is solid so quickly clears
- Frogspawn
- Finger Leather
- Goni
- Zoa's
- Mushrooms

Everything in the tank seems to be doing really well.

For the last two weeks I went to my lfs and had them test my water and here is two weeks ago.

I then started dosing one cup of my lfs magnesium a day

After one week, here were my updated params:

MG was up about 100 after dosing one cup a week and performing at least on 15-20% water change.

Salinity pretty stable at around 1.024

I have increased my magnesium daily dose to a cup and a half but the problem is that I figure it would be much higher.

Any thoughts on why it remains low (as well as my PH) and recommendations for how to improve? Or, is it just a new tank so patience is required?

I did just add a phosphate remover to my filtration in the hopes of continuing to bring that down.

Also, my LFS told me not to worry about calcium or at the moment since I don't have much in the tank requiring Calcium.

As always, appreciate the help!

Clarity: 32 gallon tank and dosing one CUP or one ML of magnesium ?

There is a relationship between calcium, alk and magnesium (and PH), so typically I hear dose all three and not just one. Maybe you need another testing 2nd opinion...

While those are heavy calcium corals, they still have skeleton, even mushroom has a bit so my target is ~440 calcium

Randy Holmes-Farley · May 10, 2021

I don't believe the magnesium result is accurate.

I'd definitely stop adding any.

Magnesium does not start low like that in quality brand mixes.

nereefpat · May 10, 2021

I agree with testing Mg with a test kit. The only way Mg would be in the 800s would be if your salinity was 25% or more too low.

ackermsb · May 11, 2021

Thank you all. I will buy a test kit today and will post the results!

Again, I would be more worried if my corals were not exploding in my tank.

NeonRabbit221B · May 11, 2021

What are you using to check salinity? What are you using to calibrate it?

ackermsb · May 12, 2021

So I bought my own test kit and Magnesium was really high (>1400)

Alk - 11.2
Calcium - 450
Mag - 1260
Salinity 1.024
Temp - Fluctuates between 76 - 80 (Is this a concern?)

I was dosing mag so stopped and dosed a bit of calc to get from 380 to 450

I also did a 18% water change last night

Thoughts?

NeonRabbit221B · May 12, 2021

What are you using to check salinity? What are you using to calibrate it?

ackermsb · May 12, 2021

Agricultural solutions salinity refractometer and calibrated with drops when i originally purchased.

NeonRabbit221B · May 12, 2021

So I would discontinue dosing magnesium until you can determine what your consumption is. Luckily high magnesium doesn't seem to harm much unless it gets very high (1500+)

Water changes are great to reset parameters so I wouldn't stop those. Take this time early in the tanks life to establish consumption and baselines. Dosing is great but without the accurate testing it can get out of whack real quick.

ackermsb · May 12, 2021

is 450 calc good or should i work to get it higher over time?

NeonRabbit221B · May 12, 2021

I run mine a tad higher (460-480) but honestly keeping with 450 is preferred by most. Given your higher alkalinity I think keeping it right around 450 is good.
I found this very helpful http://www.reefkeeping.com/issues/2002-04/rhf/feature/index.php

Randy Holmes-Farley · May 12, 2021

ackermsb said:
is 450 calc good or should i work to get it higher over time?

It's fine,. It's already above average natural levels in the ocean. IMO, 400-550 ppm is fine.

shred5 · May 12, 2021

dwest said:
I would buy a salifert mg kit and verify the low value. It seems suspicious to me.

Agreed.
Magnesium also is a harder thing to test for.

I will add that magnesium is hard to raise and can take pretty much to move the needle. That sounds like allot.

Keen4 · May 24, 2021

ackermsb said:
So I bought my own test kit and Magnesium was really high (>1400)

Alk - 11.2
Calcium - 450
Mag - 1260
Salinity 1.024
Temp - Fluctuates between 76 - 80 (Is this a concern?)

I was dosing mag so stopped and dosed a bit of calc to get from 380 to 450

I also did a 18% water change last night

Thoughts?

These numbers look a lot better than your LFS. They need to check their test kits.

Keen4 · May 24, 2021

ackermsb said:
is 450 calc good or should i work to get it higher over time?

It’s perfect

Keen4 · May 24, 2021

ackermsb said:
Hi everyone-

My 32G Fluval Flex tank has been up and running for about 7 weeks with the upgraded Fluval second light, upgrade pump (sicce syncra 1.5, (2) intank media chambers, good flow with Current USA 1,000gph pumps which are barely on.

I use red sea coral salt

Stock/Coral List:
- Clowns (2)
- Possom Wrasse
- Diamond Goby - constantly stirring up the tank but filtration is solid so quickly clears
- Frogspawn
- Finger Leather
- Goni
- Zoa's
- Mushrooms

Everything in the tank seems to be doing really well.

For the last two weeks I went to my lfs and had them test my water and here is two weeks ago.

I then started dosing one cup of my lfs magnesium a day

After one week, here were my updated params:

MG was up about 100 after dosing one cup a week and performing at least on 15-20% water change.

Salinity pretty stable at around 1.024

I have increased my magnesium daily dose to a cup and a half but the problem is that I figure it would be much higher.

Any thoughts on why it remains low (as well as my PH) and recommendations for how to improve? Or, is it just a new tank so patience is required?

I did just add a phosphate remover to my filtration in the hopes of continuing to bring that down.

Also, my LFS told me not to worry about calcium or at the moment since I don't have much in the tank requiring Calcium.

As always, appreciate the help!

What brand is that magnesium that you were dosing?