Parameters Question

[Ian Baxter]

I use Instant Ocean salt that is premixed from my LFS. My understanding is that it should mix dHK 11, Cal 400, and Mag 1350.
I don't have very many corals yet in my 65g, but there are a few expensive ones. Mostly LPS with 2 inexpensive SPS. I completed a WC today and waited about 2 hours to test and my results are below. I tested before the WC and had almost the same results as there are not many corals using up the nutrients. Why would my Mg be so high (tested with Salifert and again with Aqua Forest) and my Ca (Aqua Forest) and Mag (Salifert) be low? I know they say don't chase numbers, so would these be fine?

I do have Hanna checkers for pH, dKH, Ca, and phosphorus, but I'm waiting on the reagents and calibration fluids.

Temp - 77.7
Sal - 1.025
Nitrite - 0
Nitrate - .5
pH - 8
Ca - 350
Mg - 1650
dKH - 6.2
PO4 - .03

Thanks for the help.

 

[Miami Reef]

Time for the RMM method!

Just say NO to magnesium testing: RMM is born

OK, this thread has been many years in the making, and I'm posting it here since folks in the chem forum are probably already tired of all the threads relating to problematic magnesium testing. I'm going to propose a method, let's call it the Randy Magnesium Method, or RMM for short. All good...

www.reef2reef.com

Basically, most test kits for magnesium absolutely suck. The method in the link, made by a professional chemist, says to not bother with testing magnesium, and instead:

Use a decent salt mix at a decent salinity that has a starting level of magnesium and calcium that you like.

and this

ANY time that you add calcium, add 5-10% as much magnesium (so for 10 ppm calcium, add 0.5 - 1 ppm magnesium). If coralline is the main user of alk in your tank, use the 10%, if corals are, use 5%. A lot of products, like commercial two parts, AFR, CaCO3/CO2 reactors with suitable media, and my DIY two part systems all add magnesium for you, without measurement.

And now you don’t need to worry about testing that parameter. If you change water semi-regularly, that is even more reason not to bother testing it.

 

[Reef By Steele]

The above is ok for mag. But your dKH appears low for my liking. I would shoot for 8-9

 

[Ian Baxter]

Time for the RMM method!

Just say NO to magnesium testing: RMM is born

OK, this thread has been many years in the making, and I'm posting it here since folks in the chem forum are probably already tired of all the threads relating to problematic magnesium testing. I'm going to propose a method, let's call it the Randy Magnesium Method, or RMM for short. All good...

www.reef2reef.com

Basically, most test kits for magnesium absolutely suck. The method in the link, made by a professional chemist, says to not bother with testing magnesium, and instead:



and this




And now you don’t need to worry about testing that parameter. If you change water semi-regularly, that is even more reason not to bother testing it.

This will make things easier. I always heard the Ca tests were awful.

 

[Ian Baxter]

The above is ok for mag. But your dKH appears low for my liking. I would shoot for 8-9

I agree. How could I/ should I raise it? This was my first WC on my tank upgrade. In the 32g cube I was around 8. My plan is a 10g WC weekly. Was doing a 5g weekly in the cube.

 

[Miami Reef]

This will make things easier. I always heard the Ca tests were awful.

I was referring to magnesium, not calcium.

 

[am3gross]

When you upgraded the tank, did you add more live rock? That might be using up some of the cal and alk that you are low on.

 

[Ian Baxter]

I was referring to magnesium, not calcium.

I know. I’ve always had issues finding a good Ca test.

 

[Ian Baxter]

When you upgraded the tank, did you add more live rock? That might be using up some of the cal and alk that you are low on.

I only add some 25lbs of CaridSea dry live rock. The stuff from BRS you don’t need to cure.

 

[Reef By Steele]

You can raise your ALK with various products. I dose SeaChems fusion 2 part.

 

[jphilip813]

Just dose a lil more...All For Reef is one good one...can be a little pricey, but it works for me as well as EVC Bionic ALK & CAL)...Also, a bigger tank with more rocks, could be your culprit

 

[Ian Baxter]

Just dose a lil more...All For Reef is one good one...can be a little pricey, but it works for me as well as EVC Bionic ALK & CAL)...Also, a bigger tank with more rocks, could be your culprit

It just seems odd that I should need to dose with so few corals.

 

[exnisstech]

It just seems odd that I should need to dose with so few corals.

I would double check your alk with another test kit. I agree with the coral you have I don't think you should need to dose 2 part. My fresh mix instant ocean was 10 dKH when I tested last so I would think you should be higher than 6.2 if your doing water changes. I like to keep two kits, I use Hanna and salifert for alk. The salifert is just for comparison if I get a really strange reading on the Hanna. Have you tested salinity and alkalinty levels on the fresh mixed water you are buying? I don't test magnesium often.

 

[Ian Baxter]

I would double check your alk with another test kit. I agree with the coral you have I don't think you should need to dose 2 part. My fresh mix instant ocean was 10 dKH when I tested last so I would think you should be higher than 6.2 if your doing water changes. I like to keep two kits, I use Hanna and salifert for alk. The salifert is just for comparison if I get a really strange reading on the Hanna. Have you tested salinity and alkalinty levels on the fresh mixed water you are buying? I don't test magnesium often.

I tested with Salifert and Aqua Forest. I have the checker but the reagents haven’t been delivered yet. No, I haven’t checked the fresh mixed water for alk or salinity. Didn’t even cross my mind, but that’s a great idea. I got me tank dialed in at 1.025 using an ATO, so I assumed it was the same.

 

[00W]

Whenever outsourcing water, no matter how trusted the source, always test it.
Might be surprised .
I've never tested for magnesium so can't help there.
Lots of ways to raise alk just do your research and go slow.

 

[Peair]

I use Instant Ocean salt that is premixed from my LFS. My understanding is that it should mix dHK 11, Cal 400, and Mag 1350.
I don't have very many corals yet in my 65g, but there are a few expensive ones. Mostly LPS with 2 inexpensive SPS. I completed a WC today and waited about 2 hours to test and my results are below. I tested before the WC and had almost the same results as there are not many corals using up the nutrients. Why would my Mg be so high (tested with Salifert and again with Aqua Forest) and my Ca (Aqua Forest) and Mag (Salifert) be low? I know they say don't chase numbers, so would these be fine?

I do have Hanna checkers for pH, dKH, Ca, and phosphorus, but I'm waiting on the reagents and calibration fluids.

Temp - 77.7
Sal - 1.025
Nitrite - 0
Nitrate - .5
pH - 8
Ca - 350
Mg - 1650
dKH - 6.2
PO4 - .03

Thanks for the help.

You might have dose too much magnesium, do a water change and retest.

 

[Ian Baxter]

You might have dose too much magnesium, do a water change and retest.

I don’t dose mag. I recently tested my LFS water and their alk was 5.4. So now I make my own and everything is good after the first water change yesterday except the alk is a tad low. Been dosing that and slowly raising it for the last week.