Cape Town south africa

I have bn struggling to get the water correct for sometime but since the beginning of last year I got my algae problem soughted without iv light. My fish payed eggs but I was not prepared because I did not think they could at that size so I lost all as I did not have any plants in my pond but this year spring I will be prepaired

3000mm x3000mm x 900mm
Concrete pond

Assorted koi and butterfly koi