Warning: Don't raise Mg too fast

[mokusei]

I have read that one should not raise Magnesium levels by more than about 200ppm in one day. Well, today I proved this to myself when I miscalculated and accidentally raised my Mg by ~240ppm (from ~1080ppm to ~1320ppm, Salifert). I did this by mixing MgSO47H20 USP (pharmaceutical grade Epsom salt) with RODI water and adding it to my tank.

The result: within 45 minutes several Astraea and small Stomatella snails fell ill. They have not died yet, so I suppose there is some chance that they'll recover.

I have since done a large water change, which I hope will prevent further casualties. So far none of my other livestock (including Cerith snails, Bali Red Fromia Starfish, Rainford's Goby, Favites, Acan echinata, Acropora, Seriatopora, Montipora, Zoathids, GSP, Xenia, mushrooms, chalice, Caulastrea, clove polyps, Porites, Fungia) has shown any obvious negative reactions.

My uneducated guess is that the snails were affected by the rapid increase in specific gravity. I would welcome other opinions on this.

 

[HighlandReefer]

Could be the salinity and it could be from the contaminates found in mag sulfate as well as mag chloride. FWIW, it is not recommended to raise your mag. level by more than 100 ppm per day per Randy. Snails and other invertebrates are particularly sensitive to heavy metals. Raising salinity by more then 0.002 is not recommended in reef tanks either.

 

[mokusei]

Good news. The Astraea snails appear to have recovered. Unfortunately some of the juvenile Stomatella hitchhikers did not.

These articles confirm what Highlandreefer wrote about the 100ppm recommendation:
http://reefkeeping.com/issues/2004-05/rhf/index.php
http://reefkeeping.com/issues/2006-07/rhf/index.php

 

[Allmost]

Could be the salinity and it could be from the contaminates found in mag sulfate as well as mag chloride. FWIW, it is not recommended to raise your mag. level by more than 100 ppm per day per Randy. Snails and other invertebrates are particularly sensitive to heavy metals. Raising salinity by more then 0.002 is not recommended in reef tanks either.

wouldnt it be the increase in so4 that harms the snails ? it is increasing the salinity as well as increasing sulfate while chloride stays the same so making the water imbalanced ?

for my dosing I add 550 g of mg chloride, and only 80 grams of mg sulfate, in 2.5 G of RO water, and I have mistakenly increased the mg over 300 PPM and no ill effects ! so could it be the imbalance that kills the snails ? and change of salinity ? rather than heavy metals ? (cause the salts I use and he used are lab grade so must be low in other metals) I could be wrong though

 

[NaClH2Opgh]

I can tell you from experience when I raised my mag to battle bryopsis I kept my levels around 2000. I raised it quickly initially when going from 1300 to 1800 and all my snails looked like they were dead. They just became lethargic (not sure it that applies to snails but we'll go with it) and moved verrrrry slooowly but continued along. I added about 5 larger snails during this time of elevated mag and they died within 2 days. I know for certain because these turbo grazers were larger than the ones I had in my tank. When I let my mag levels drop back down to 1500 the snails I had in my tank from the beginning were back to normal.

 

[chuckreef]

Did you just pour the whole mix in at once?

 

[bertoni]

The problem with the sudden rise could have poisoning from impurities in the magnesium supplement. That'd be my first guess. I do agree that very high magnesium levels, over 1500 ppm or so, could be a problem, too.