There are pieces of equipment that can make caring for you koi pond easier (even if it doesn’t’ have fish!). An Autofill is one of those things. Before installing one, consider all the pros and cons.
Wait- What is an Autofill?
It is a device that automatically adds water to the pond when levels dip below a certain point. It is most often found inside the skimmer box and resembles the thing inside your toilet tank. There are a couple different types and sizes you might come across. The one below is a large autofill.
They are typically tied into your sprinkler system and are part of a zone. When the float goes down with the water level and that sprinkler zone comes on, it will add water until the float is up high enough again.
When the sprinkler system is off for any reason, like being off for the winter, the autofill will not work. generally in the winter there is less need to add water.
They can also be tied directly into a water spigot.
How Often Does a Koi Pond Need Water to be Added Without an Autofill?
In Colorado, a normal amount is 2 to 3 inches a week, no matter how large the pond is. If your pond is roughly 5 x 5 and you add 2 inches, that is roughly 31 gallons of water. (if it’s 10 x 8 it would be approximately 175 gallons). The reason the pond needs to be filled is that evaporation works on the pond and we have to add more water.
During the winter evaporation is a lot less. In the spring evaporation is about 2″ but when it gets hot, over 80° evaporation is more. 3″ is normal each week in hot weather.
When is Pond Water Loss NOT Evaporation?
If the pond is losing more than 3 inches in one week – it may be water loss. Read about potential leaks HERE.
Here are the PROS of Using an Autofill Valve in a Koi Pond
Convenience: Autofill valves eliminate the need to drag the hose out and top off the pond. For pond owners who travel frequently or have busy schedules, this can be a significant advantage.
Consistent Water Levels: Consistent levels keep aquatic plants that are planted inside the edge of the pond from getting too dry and dying.
Prevents Pump Damage: If the water really gets low, it can cause a pump to run dry, potentially leading to overheating and damage. You might even have to replace a pump that has burned out. An autofill valve ensures that the water level never falls below the minimum required for safe pump operation.
And CONS of Using an Autofill Valve in a Koi Pond
Space: Sometimes an autofill makes it difficult to remove the pump in the skimmer. It is sort of in the way. If you still want one, use a compact Autofill. (photos below)
Malfunction Risks: Like any mechanical device, autofill valves can fail. Especially if it has been bumped into while doing other pond maintenance. It can mess up the level that the float is at. If a valve fails in the open position, it could lead to overfilling, possibly flooding areas around the pond. I’ve seen this happen and had one very panicked client because it was flooding into the golf course right by his house!
Conversely, if it fails to open, a homeowner may not realize it and the pond could dry out. It could ruin the pump and kill the fish.
Masking Water loss: If a leak develops from low liner on the edging, a faceplate seal that wears out, or something else, you may not be aware of it because the autofill just keeps filling the pond to the perfect level. You might suddenly get a really high water bill or notice a crazy outbreak of string algae. (string algae loves fresh water!) Read more about that HERE.
This is the compact autofill valve.
Maximize the Benefits of an Autofill
And minimize the risks!
Install a ball valve: Put in a ball valve in the pipe before the ball valve. This allows you to easily turn it off
Regular Checks: With an autofill valve, regularly check to see if it is running continuously. You can even temporarily turn it off by turning off the sprinkler zone it is associated with for a day and measure the level of the water from one day to the next. If you have a ball valve, close the valve to do a check.
Professional Installation: Ensure that your autofill valve is installed correctly by a professional. This can help prevent common issues such as leaks or improper water level settings.
This type of autofill valve, called a Hudson Valve, can be used inside or outside a skimmer. The trick with this one is that it has to be installed PERFECTLY straight up and down. They are most often found in pond-less waterfalls. The floating part is actually inside the cylinder. A closer look at it found below.
Kristi's Tips
For me, one of the worst parts about manually filling the pond is that I might (not that I’ve ever done this before…) forget that the hose is on in the pond. My tip is: set a timer on your phone or iWatch for 15 or 30 minutes to check. Then set it again if it needs to be filled more. Letting a hose run on and on can cause lots of problems including fish loss!
If an Autofill is right for you, I highly recommend also using an Autodose. It puts in beneficial bacteria and water conditioner on a regular basis. This is important if the Autofill is adding chlorinated water. There is dechlorinator in the Autofill.
If you want to turn off the autofill temporarily without turning off the sprinkler system (no one wants the grass to get brown!) use string to tie up the autofill, holding it in place. Tie it to something nearby just temporarily to make sure there is no water loss with out it.