Rhodactis reaction to magnesium

[dnjan]

I was adding some magnesium supplement (Tropic Marin Bio-Magnesium) to the tank and noticed that all three of the Giant Green Metallic Mushroom Anemones (Rhodactis sp.) in the tank "onioned". Didn't notice any change in the other corals.

Just an observation ...

 

[Juanfer]

are they close the the flow(I mean did you add the magnesium directly in your flow) maybe you added next to them???

 

[dnjan]

I added the magnesium directly in front of my return (seaswirl), and the three Rhodacti are not directly downstream.

They opened back up a few minutes later, but I was quite surprised that all three had the same response, while the polyps of montiporas, pocillaporas, tubinaras and alveopora did not appear to have any response.

 

[steve-s]

Was the additive a liquid or solid?

Keep in mind that this stuff is salt in a different chemical form. If concentrated and added to the tank, some animals will react negatively if they get full exposure. Best to add either in the sump or diluted with top off water.

 

[mmkeeper]

I add all my stuff into the overflow.

 

[dnjan]

I add the magnesium supplement slowly, in front of the sea-swirl outlet, and the water movement initially pushes the chemical away from any animals (unfortunately, much of my return flow has to bounce off the front glass before it gets anywhere useful).

I definitely agree that it is not good to subject te animals to strong salt gradients. I just thought it was unusual that it was only the Rhodactis (and one of them was quite far away from where the bio-mag was added) that reacted. Are they that much more sensitive? Or does magnesium trigger a response for them?

 

[steve-s]

I just thought it was unusual that it was only the Rhodactis (and one of them was quite far away from where the bio-mag was added) that reacted. Are they that much more sensitive? Or does magnesium trigger a response for them?

Could be they got most of it if the flow followed a laminar path. Could also be the coral in between did not have the ability to show this kind of reaction?