Magnesium dropping, not sure why..

[Pawlu]

So my average magnesium reading use to be a steady 1340 ppm for a long time. I last tested it about a month ago and it was 1340. Today I decided to test it before my weekend water change and I was surprised to get a reading of 1110ppm.

I decided take a reading from my fresh salt water mixing container and it was higher but still lower than usual, I got a reading of 1125ppm.

Over the last month I started dosing 1 teaspoon of Kalk per 2.5 gallons of RO top off water, it goes through 2.5 gallons in approx 1 week (5-6 days). I also started dosing Aqua Vitro 8.4 to bring up my pH which was also too low. My pH is now around 8.1 peak during the day and drops to around 7.8 at night (Still an Issue that I am working on resolving and reducing the large pH swing).

Any idea why my magnesium is dropping? Do corals consume this at a similar rate as calcium (which I also noticed has started to drop), I have a mix of soft corals and montipora's which are both growing).

Thanks

 

[plasma327]

How old is your testing Kit? Are you getting new coralin growth? Added any new coral? How old is your tank?
I would not chase the ph. It will come up over time and stabilize. Supply some more info on your system..

 

[Pawlu]

system is 1 year 2 months to date, no have never been able to get decent coralin growth, however my SPS corals are growing at a much faster rate than they did, growth increased approx 2 months ago after the tanked aged 1 year, it also increased after I started dosing Kalk. As for test kits, they are about 8 months old, (Salifert). As for pH, prior to adding some aiding buffer pH would drop below 7.8 at night and never go above 7.9 during the day. Should soon not be too big an issue as spring will be here and I can open up some windows, however as a plan of attack for next year I plan on using co2 scrubbers to try and tackle the drops and swings.

My calcium ready is (as of today) 425ppm, my Alkalinity is 9.3dKH. Was thinking of increasing my kalk dose to 1.5tsp per 2.5 gallons.

 

[reefer gladness]

It's a combination of the salt mix and the kalkwasser. Not sure if you switched salt mixes or maybe an inconsistent batch, it happens.

Kalkwasser use definitely increases magnesium use. I can't explain why but this has been noted by many others, something is precipitating. I myself dose large amounts of magnesium daily just to maintain. If you don't keep mag up then it becomes more difficult to maintain alk and calcium too.

 

[Pawlu]

Actually i just opened a new bucket of salt, same salt mix as i usually use, just a fresh bucket. If kalk gradually increases mag then Increasing kalk dose to 1.5tsp per. 2.5 gallons should help maintain the declining mag.

 

[reefer gladness]

Actually i just opened a new bucket of salt, same salt mix as i usually use, just a fresh bucket. If kalk gradually increases mag then Increasing kalk dose to 1.5tsp per. 2.5 gallons should help maintain the declining mag.

Maybe I didn't state this correctly but kalkwasser is going to deplete magnesium from your system not increase it. Something about the kalk mix that causes magnesium to precipitate out of the water I think. Anyway, just note if you increase kalk use your mag will probably drop even faster.

 

[Pawlu]

Ok so what should i start dosing to maintain mag?

 

[reefer gladness]

Ok so what should i start dosing to maintain mag?

Yes, either you need to dose to maintain mag or you may be able to switch salts to one that has a higher mag content. A few salts seem to have elevated mag levels around 1500ppm, I think Reef Crystals might be one with high mag but not sure.

 

[Pawlu]

I use reef crystals with added calcium, as for dosing, any recommended product and method?

 

[reefer gladness]

I've always used Kent Tech-M. I'm sure other brands are okay to use also, I just noticed the Tech-M seems to have a higher concentration of magnesium which makes it cheaper to use compared to some brands.

A dosing pump would be ideal but not at all necessary. I just add a few capfuls every day myself.

 

[PSU4ME]

I use kalk +2 by brightwell aquatics to combat this.....it contains magnesium in the kalk. Works well.

 

[reefer gladness]

I use kalk +2 by brightwell aquatics to combat this.....it contains magnesium in the kalk. Works well.

Cool stuff, I'll have to try that myself when the current bucket runs out. I've been using Kent and Seachem kalkwasser.

 

[PSU4ME]

To me it seems much cleaner than seachem, less leftover. Give it a shot

 

[Pawlu]

Thanks for the tips!