What to do with overdosed Magnesium

[pandadoc]

I inadvertently dosed too much Magnesium into my system with a Litermeter III dosing pump overnight-approximately 3/4 gallon from a Bulk Reef Supply mix. Tried to measure Mg concentration with Salifert kit, but it is over the limit of the test at 1500. The tank is 120 gallons, and with the sump, the volume is 134 gallons. The tank is predominantly an SPS tank with some xenia, but no fish at this time. There are invertebrates in the form of snails, shrimp, crabs. After one day, there are no changes to the Acropora or Montipora colonies in color. Should I do a massive water change or allow the system to purge Mg slowly via automatic water changes of 2.5 gallons per day with the Litermeter? What is the long term effects of too high a magnesium concentration?

[Randy Holmes-Farley]

Water change is the only way to reduce magnesium.

You probably boosted magnesium by about 400 ppm. At that level (maybe 1700 ppm), I would not go with massive changes unless you saw a problem.

[pandadoc]

Thanks Randy!

Do you know if high Mg would have an adverse effects on fish?

[Billybeau1]

I'm not Randy, but I say no. I've had my fish only up to 1800 ppm for a month with no noticeable fish problems. :)

[Toadally]

My tank constantly stays at 1680 ppm and dosen't seem to have any bad effects. I'm using RC and doing 2% wc daily. I assume this is the reason.

[pandadoc]

Thanks guys,

Good to know that high Mg doesn't have more serious consequences! I will continue doing the daily water changes using my mixture of RC and Coralife salt and hopefully the Mg levels will come down slowly to the normal range.

[Randy Holmes-Farley]

:thumbsup:

Good luck and let us know if anything notable happens. :)

[tmz]

If you refill the syringe and add more titrant to the sample, I believe you can read levels higher than 1500ppm with the salifert kit by adding the 2nd result to the 1500ppm. FWIW ,the coral life salt you are using has high mag levels. I use it and mag hangs around 1500ppm without any supplement.So it may be difficult to reduce the mag level using this salt.

[maroun.c]

+1 to above refill syringe and add the new result you got to 1500. at least you'll know where your Mg really is.

[evsalty]

If you have/had any hair algae you won't any more lol.

I have been currently testing my RC salt freshly mixed to 35ppt @ 80* and it consistantly measures around 1320-1340 for mag. IO claims 1345 mag for the RC salt and as you can see I get near it consitantly.

Like said above, if you refill the syringe and continue to add #3 I believe every .1 used is equal to 30ppm. The instructions actually mention this towards the end.