Mg media - decaying coralline

[euphylius]

There are several Grotech Mg media users, who observe similar effects. Randy already explained high alkalinity but there is another worrying effect. Coralline algae are decaying. Did somebody else notice something similar?

[Randy Holmes-Farley]

Coralline algae are decaying.

Are corals and other inverts unaffected?

[euphylius]

Beside me in one case all corallites decayed in three days (dKH change from 7 to 12,5 in ten days), and two others are reporting falling corallites from the glass.

All we are (were) using Grotech Mg media in CaCO3/CO2 reactor.

Nobody is reporting any other effect.

[Randy Holmes-Farley]

corallite means coralline algae? Not corals?

[euphylius]

Yes, that means corallites algae.

Regards, Euphylius

[Randy Holmes-Farley]

I don't know what might selectively kill coralline algae that could come from a magnesium carbonate material. :(

[simonh]

I did read an analysis of the Grotech Magnesium pro a year of so ago (it is now pay-per-view) http://www.lars-sebralla.de/ma_mg_pro.html

About the only thing apart from major elements was some aluminium in the media, around 100mg/kg. Most other elements were below 0.01% wt.

[Randy Holmes-Farley]

Thanks, Simon. :)