Need Advice on Koi Pond Setup

[pm-koi]

Hi everyone, I’m looking for some help with my koi pond. I’ve attached rendered perspectives showing the layout and system, including the filtration setup.

Here are some issues I’ve been dealing with:

• The water stays a bit green and cloudy/blurry most of the time.
• Some of the fish die every few months/year without clear cause.
• The pH drops quickly every time it rains.
• The fish are also reluctant to eat floating pellets, even though we feed them regularly.

We do routine partial water changes and always monitor the pH and salinity. I’d really appreciate any thoughts on whether the pond system itself might need improvements or if there's something wrong with the overall pond setup. I’m open to suggestions on what to change, add, or fix to make things more stable and healthy for the fish.

Thanks in advance for your help!

[Noahsnana]

To start because of fish dying issue and PH drop... Get an KH test if low you may need to add baking soda to buffer water to bring up PH

[aquaholic]

What is your level of fish expertise/experience?
Knowing that makes it easier to provide useful levels of information to you.

You have several issues so tackle each one separately and methodically until they get solved.

- The water stays a bit green and cloudy/blurry most of the time.
* Look at your UV filters. Have you changed to new lamps? Have you cleaned the quartz tube? Are the UV's wattage high enough for your water volume? Is the flow rate through UV's fast enough to overcome the green water (algae) reproduction rate? Yet slow enough to get good kill rate each passthrough? Is there particulate matter obscuring efficiency of UV penetration ?

- Some of the fish die every few months/year without clear cause.
* What is your ammonia & nitrite levels? Are you overcleaning the biofilter?
* The most common cause of ornamental fish deaths is overfeeding.
* How many fish/what size fish in what water volume? Are you over stocked? How much water is changed and how often?

- The pH drops quickly every time it rains.
* Add large amounts of shell grit to naturally harden/buffer or baking soda.

- The fish are also reluctant to eat floating pellets, even though we feed them regularly.
* What brand pellet? How old? Are they palatable? Are you simply overfeeding? Have you tried other quality brands of floating pellet within expiry date?