Any way to reduce Magnesium

fragit · Mar 30, 2017

I've been using AquaForest Probio reefsalt, and my Magnesium has been way too high for too long, getting number of like 1460 using RedSea Pro test kits. I'm going to be switching to Fritz RPM salt this week, as I have had nothing but trouble keeping sps corals since switching to Aquaforest products. I have not dosed Magnesium in like 2-3 months yet it still remains in the high 1400s. No I have not tested freshly mixed salt water. Is there anything I can do other than a large water change to reduce magnesium? Should I even bother can it cause issues with sps corals?

Anirban · Mar 30, 2017

High magnesium at least upto 1500 ppm does not really cause any damage. Are your Ca and Alk stable and decrease? Do you dose to keep them up? Magnesium is already quite high in sea water so to show toxic effect it needs to be significantly elevated which we generally don't encounter in reef tanks.

Randy Holmes-Farley · Mar 30, 2017

Many people get too high of readings from the Red Sea kit, and 1460 ppm is OK anyway.

I wouldn't try to reduce it, which can only be done by water change with a lower magnesium salt mix.

fragit · Mar 30, 2017

Anirban said:
High magnesium at least upto 1500 ppm does not really cause any damage. Are your Ca and Alk stable and decrease? Do you dose to keep them up? Magnesium is already quite high in sea water so to show toxic effect it needs to be significantly elevated which we generally don't encounter in reef tanks.

Yes I do have to dose Alk and Ca to keep stable. Alk runs 8.3-8.5dkh, and Ca 420ppm every time I check. I check Alk almost daily and at different times, and test Ca a couple times a week. I've been using BRS 2 part for about 2 months.

Anirban · Mar 30, 2017

fragit said:
Yes I do have to dose Alk and Ca to keep stable. Alk runs 8.3-8.5dkh, and Ca 420ppm every time I check. I check Alk almost daily and at different times, and test Ca a couple times a week. I've been using BRS 2 part for about 2 months.

Still your mag never drops beyond 1400?

fragit · Mar 30, 2017

Nope, it does not. The only thing I can attribute it to is the AF salt. There was a thread going around where a user was getting readings in the 1600s I think on freshly mixed salt. I'm going to be mixing some to use on my fish QT and will check it to see what it is.

Anirban · Mar 30, 2017

fragit said:
Nope, it does not. The only thing I can attribute it to is the AF salt. There was a thread going around where a user was getting readings in the 1600s I think on freshly mixed salt. I'm going to be mixing some to use on my fish QT and will check it to see what it is.

At what salinity you mix it generally? Also all the bad reports I have seen are related to reef salt but this is the possibly the first one with probio..

fragit · Mar 30, 2017

Anirban said:
At what salinity you mix it generally?

1.025 at 78degrees

Reefaddict305 · Mar 30, 2017

Mangroves will do the trick.

Anirban · Mar 30, 2017

fragit said:
1.025 at 78degrees

Where do you get your salt from?

hypnoj · Mar 30, 2017

I'd love to keep my Mag that high all of the time, nice problem to have. What salt is that again? I'm gonna switch to it next box.

fragit · Mar 30, 2017

Anirban said:
Where do you get your salt from?

I got that from salty supply last fall.

fragit · Mar 30, 2017

hypnoj said:
I'd love to keep my Mag that high all of the time, nice problem to have. What salt is that again? I'm gonna switch to it next box.

AquaForest Pro Bio reef salt.

Anirban · Mar 30, 2017

fragit said:
I got that from salty supply last fall.

I am just wondering that without dosing Mg how your system maintain such high magnesium. As you say you dose two parts that means your system uses Alk and Ca which also means it uses Mg too. Then how that much remain in the system is interesting.

kennedpa · Mar 30, 2017

If your fish QT isn't the same salinity you mag may differ.

How large and often are your water changes? Do you have algae as part of your nutrient export.

fragit · Mar 31, 2017

Anirban said:
I am just wondering that without dosing Mg how your system maintain such high magnesium. As you say you dose two parts that means your system uses Alk and Ca which also means it uses Mg too. Then how that much remain in the system is interesting.

I've been wondering too, I only have a few frags. Coralline algae is really taking off, so that's probably accounting for most of the uptake of alk and calc. I have to dose about 72 mL of both daily.

kennedpa said:
If your fish QT isn't the same salinity you mag may differ.

How large and often are your water changes? Do you have algae as part of your nutrient export.

I do a 10-15gal WC every two weeks. Fish QT is same water as tank, meaning old tank water goes into fish QT.

Anirban · Mar 31, 2017

fragit said:
I've been wondering too, I only have a few frags. Coralline algae is really taking off, so that's probably accounting for most of the uptake of alk and calc. I have to dose about 72 mL of both daily.

If your coralline algae is taking off then in that case with such high Mg a good amount of it should be used to pack into their Ca-carbonate deposits. This in turn will reduce Mg pretty fast. But in your case its not happening at all. So, I doubt that the issue is somewhere else. Possibly your test kit because even if your salt has very high Mg which I doubt can not be beyond 1600ppm at max but still during a week without dosing it will fall quite fast. Then a single 10% water change is not sufficient to pull it back to 1600 again. This way slowly it will fall down. But you are saying you did not even dose Mg for 2-3 months which sounds pretty odd.

Randy Holmes-Farley · Mar 31, 2017

Reefaddict305 said:
Mangroves will do the trick.

I don't agree. I think this is mostly a myth. You'd need huge plants dripping magnesium outside the tank to drop levels by large amounts.

Have you observed it?

Randy Holmes-Farley · Mar 31, 2017

Anirban said:
If your coralline algae is taking off then in that case with such high Mg a good amount of it should be used to pack into their Ca-carbonate deposits. This in turn will reduce Mg pretty fast. But in your case its not happening at all. So, I doubt that the issue is somewhere else. Possibly your test kit because even if your salt has very high Mg which I doubt can not be beyond 1600ppm at max but still during a week without dosing it will fall quite fast. Then a single 10% water change is not sufficient to pull it back to 1600 again. This way slowly it will fall down. But you are saying you did not even dose Mg for 2-3 months which sounds pretty odd.

Pretty fast? Like 1-2 ppm per day.

Reefaddict305 · Mar 31, 2017

Randy Holmes-Farley said:
I don't agree. I think this is mostly a myth. You'd need huge plants dripping magnesium outside the tank to drop levels by large amounts.

Have you observed it?

I mean that's fine you can disagree, I'm saying because of my own personal experience that's all.