Magnesium dropping rapidly

[Chris918]

Hello,

I'm using Coral Pro Salt in a tank designed to grow out SPS frags. I'm using Red Sea's Reef Care Recipe and try and aim for the parameters listed on the bucket. I tested four days ago as instructed and kept my salinity stable to try and determine how much I need to dose each day. Here were the changes:

Calcium: 450 to 440 ppm
Alkalinity: 11.8 dKH to 10 .7 dKH
Magnesium: 1350 ppm to 1290 ppm

I'm not surprised by the first two tests, but I'm shocked at how quickly Magnesium drops in this system. Does anyone have any ideas why this may be happening? To my understanding, Magnesium is normally only dosed 1-2 ml per day per 25 gallons.

Thank you for any help

 

[Uncle99]

Testing error?
Assume you are using The RED SEA test kit.
I find it hard to get exactly 1ml in that syringe so results can vary.
Test again?

Just as a side note, I calculate uptake by recording changes averaged over a month, hobby grade test kits are not that accurate.

I have had mag change as much as yours within 2 tests five minutes apart.

 

[Chris918]

I'm actually using the Salifert Test Kit. I appreciate the information. I'll do a few repeat tests and hopefully we can get a reading that makes more sense. Are Salifert tests a good quality choice or should I aim for another brand?

Thanks!

 

[hkgar]

Salifert kits are very good, considering they are "hobby grade" I use them for Mag and calcium. Hanna checker for dKH

Why do you want dKH at those levels. The coral uptake will be what it is. They do not take up more just because the level is high. For SPS appox. 8.0 is sufficient.

Here is a great read on maintaining/growing SPS

 

[Uncle99]

I believe that is the RED SEA PRO salt mix range.
When I use this salt with a weekly 15% change, no dosing is required on my 75g with about 60 Stoney’s

There’s a lot of talk about increased calcification at higher levels provided PH remains stable in the 8.2-8.3 range. That said, I have seen no proof of this, just talk.

 

[thegrun]

One thing to remember when testing your magnesium is that you need to follow the instructions exactly, the required swirling duration is critical. It is also possible that you either have a bad batch of salt which happens a little more frequently than you would think or perhaps the magnesium isn't distributed in the bucket very well. It's a good idea to mix up the salt before you make saltwater. I would test a fresh batch of saltwater and see what it reads.

 

[DSFIRSTSLTWATER]

Is having a high dkh bad? I'm fairly new and my dkh tests around 10-10.5 I also use salifert for my tests. Gonna follow this for a bit

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[thegrun]

Is having a high dkh bad? I'm fairly new and my dkh tests around 10-10.5 I also use salifert for my tests. Gonna follow this for a bit

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It can be, but big swings are far more damaging. Many quality tanks run run their alkalinity at 10.5 or even higher, but they are consistent at those levels. You get better color in your SPS at a dKh closer to 8.0, but more growth at a higher level.

 

[DSFIRSTSLTWATER]

It can be, but big swings are far more damaging. Many quality tanks run run their alkalinity at 10.5 or even higher, but they are consistent at those levels. You get better color in your SPS at a dKh closer to 8.0, but more growth at a higher level.

Hmm interesting. So I guess I won't worry that my levels barely move than thanks[emoji846]

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