Changing Water Changing Parameters

[Darth_Tater]

So I made a rookie mistake last week and messed up a Magnesium test. It read very low, and instead of double checking I dosed some Mag. This ended up putting my Mag level off the charts (literally, all I know is it was above 1600).

After realizing my mistake, I decided to do a series of 10 gallon water changes every day until the Mag dropped to where I want it (about 70 gallons in the system). After 2 days of this I realized the new water I was adding was throwing off my other 2 parameters as well since the newly mixed saltwater has a much higher Alk level than I want. This was causing stress to my SPS.

I've decided now that the best course will be to just leave the Mag dosing pump off and reduce the Alk dosing amount and let things slowly settle and track the parameters every couple days until they drop to where I want them.

If anyone has other recommendations I'd appreciate them. I'd also like some ideas on how to do large water changes without throwing all the parameters out of whack for future reference. Is it best to keep the parameters close to the newly mixed saltwater? Or am I missing something? Thanks!

 

[Vorog]

It sounds like you did the best thing. I too have had this happen and just let things slowly work itself back to stabilizing. I have done two large water changes on my system (90 gallons of actual water volume) I try to measure everything on the tank as well as the new water to make sure they are the same temp, ph , salinity, cal,all,mag etc. it seems not matter how careful you are the system will still be somewhat shocked. So I like smaller more frequent water changes.


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[billdogg]

Just leave it all be. The magnesium will drop slowly over time. FWIW - I don't use a dosing pump for Mg - When I test and it's low, I just pour in however much the BRS calculator says it needs.

 

[Ron Reefman]

+1 to what others have said.

For what it's worth, I ran Mg levels up to 2200 trying to kill off an algae. It did no harm.

 

[Darth_Tater]

Ok, thanks for the sanity check everyone!

FWIW - I don't use a dosing pump for Mg - When I test and it's low, I just pour in however much the BRS calculator says it needs.

I have a 3 pump doser so I am dosing the Mag so I don't feel like I wasted money. It's a very small amount, something like 5 mL a day (vs. the 150-ish mL a day of the other 2).