Hello there:
I service and repair pools by trade and I have been tasked to rehab a Koi pond that has fallen on hard times. I have some general pond knowledge but as many of you have seen searching the web, the information available for ponds isnt' all that consistent.
it's a 5000 gallon pond with 6 or 7 18" koi in it. it's very murkey. The filter system consists of a pond skimmer with a 1.5hp submersible pump in it. Water is pumped to an upper 200 gallon basin and then spills down over some rocks into main body. I assume the skimmer gets those filtering pads which are currently missing of the jobsite. There is no filter media in the upper basin.
I feel it's a sound foundation to work with but I need help in getting this thing back on it's feet. I'll run my plan by you all and please feel free to critique/suggest or even tell me I have no clue lol.
-Drain 20% and refill adding chl nuetralizer and stress coat
-obtain 1 fine and 1 course filtering pad to place in skimmer
-put bio balls or lava rock in upper basin
-clean out the stuff growing into the pond. (looks like beach grass to me)
-Put some floating plants in
-wait a week or 2 and do an additional 20% drain/refill.
An alternative plan suggested to me by a pond company we deal with is to fill a couple of large barrels with exsisting pond water, put fish in it, and completely drain and refill. The guy I talked to over there seemed like a bit of a sociopath and I'm not sure I fully trust what he said.