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[oswoldy]

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[-Nemo-]

Which test are you using?

450 Calcium is actually perfect.
Retest the magnesium just in case.

 

[seffieuk]

Calcium is at a good rate for hard corals but the Mag is too high, should be around 1250-1400 ppm.

Make up a batch of salt water and test for mag - if it is very high you may need to consider buying a different salt with a lower Mag level to help bring the level down.

Seffie x

 

[seffieuk]

It will come down a bit when you do your fresh water top offs - you are topping off with non salty ro water aren't you?

Seffie x

 

[seffieuk]

I suspect you are getting some loss of tank water, maybe not much but over time this will have an effect on many things, one of which will be sg as you are in affect topping off with salty ro water.

See if you can top off every night with pure ro water, even if it is only a litre or pint

Seffie x

 

[seffieuk]

As long as you keep the water cold and in the dark that will be fine

Seffie x