While working on my waterfall, my gardener dropped a heap of cement (cement/sand/Plaster Key mix) in the pond. At that stage the pond was half full. I opened the tap, added koi clay (2 cups) and Sodium thiosulphate. I also started the venturi again and also added my air pump. I can obviously not switch the waterfall on.

The koi are not really distressed, not gasping, but one jumped.

Should I wait and see, or empty the pond and refill again. I do not have quarantine facilities.

Please don't laugh- my wife is not even suppose to know what chair I'm using!

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Albie,

The pH will go sky-high! Get the Koi out or do as much water changes as possible to bring the pH down and the water is clear!
The “mix” could also block your pipe work and filter.

albie afhangende van die hoeveelheid mag dit miskien nie te-erg wees nie maar ek moet se jou water lyk baie erg. (Ek het dieselfde fout gemaak verlede jaar - maar nie so erg nie)

Verander baie water elke dag en monitor jou PH

As jy 'n kleinerige dam het sal ek miskien aanraai om al die water uittehaal, dam skoon temaak en nuwe water intesit.

Maybe the gardener will be happier than Cleopatra to bath there.
To be serious now, I had 8 cement blocks in my 4 filters and the pH remained at 8.5. When I went back to SA after a few weeks I ‘found’ the problem. I removed the bricks and pH 7.6 now. Like Pieter said, your piping will clog up with the cement and will harden over time causing serious problems.
Don’t show the photo of the chair to your wife, a water change won’t solve that issue

They are all out- in the bath and I have cleaned the pond. What a mess!

Thanks for all the advice (not sure if my wife will be happy about her bath- I will probably sleep somewhere else tonight; she's still at work)