Nearly ready for fish except

Ringwood

AC Members
Mar 29, 2005
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Ringwood, England
All the readings seem to be levelling but the PH is 9.0, is there a way to bring the PH down?

I realise this maybe because I made the rocks in the tank from a mix of Portland cement/medical plaster of Paris and did not let them soak in fresh water long enough.

But the tank actually looks quite good with the rock layout and algae has started forming on the rocks, and I really don’t want to move them out and wash them some more.

Any Idea’s

Thanks Mike
 
I'm a civil engineering student and concrete can be nasty stuff when mixed with saltwater. It will react with the silicates in the water and generally degrade from this. Fresh concrete will also leach lime into the water for some time. Concrete will continue to cure or harden as long as there is enought water for the hydration process to continue. How long did you cure the concrete in fresh water? I'd say a minimum of two months to be on the safe side with regular water changes.
 
The calcium it release will actually be good for a reef set up but, you might have to let it cure in fw for 4 or 5 months. there isn't a way to rush the process but, it does have it's own rewards as you can get exactlythe set up you're dreaming of.
 
Remove Some Rock....

I am going to take out the concrete which I beleive was the last produced and only cured for a couple of weeks and set it up to cure somemore. Then I can test the tank again after a water change and see if the PH has gone down. If its at a much lower level I will just be waiting on the last produced to cure. If its not much lower I will remove whats left and recure that as well.

Thanks to everyone Mike
 
There are some guidelines on curing concrete on the Garf website; you might check there...
 
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