Good, The Bad, and the Ugly)
devices have become more and more common in water garden installations.
The idea of keeping the pond full at all times is great. An auto-fill
is hooked up to a water source so that when the pond's water level
drops due to evaporation. A float is installed at the level of
the water surface, as the float drops with the water a valve is
opened allowing new water to enter the pond.
Most auto-fill float valves do not remove chlorine from the water.
Small amounts of chlorine will dissipate on its own before harming
fish. Any amount of chlorine can harm the gills of your fish,
prolonged exposure or exposure in high doses can kill the fish.
If using a float valve, you may wish to add a little dechlorinator
on a regular basis to help neutralize the tap water additives.
There are kits like the PondFil Float that use a cartridge filter
that removes chlorine from the water prior to entering the pond.
A leak in the pond may go undetected using an auto-fill.
When a leak occurs you will be adding larger amounts of new tap
water and larger amounts of chlorine, eventually leading to gill
failure in the fish and ultimately death.
Mechanical parts don't last forever. When the float valve
fails this could mean a constant flow of tap water entering the
Auto-fill float valves can save you the trouble of dragging
a hose to your pond when evaporation drops the water level. This
can be a big help, but if using this type of device it is good
to have a little knowledge of the benefits and risks and to monitor
the fish and the valve regularly.