Water features are usually very low-maintenance. But once in a while, you’ll encounter problems.
The water level keeps dropping.
Especially in warmer weather, water can evaporate from your water garden surprisingly quickly. Top off as needed with a hose. If more water is disappearing than can be explained by evaporation, check any tubing or connections. There may be a leak or loose connection, and it will be evidenced by soggy soil at the site of the leak. Or you may have a leak or tear in the liner. Drain the pond to see if you can spot the problem. Then use a patch kit to repair the liner. Otherwise, you may need to replace the liner.
The GFCI trips repeatedly.
A GFCI may trip every few months or so, and still be in good working order. However, a GFCI that trips more often and goes unattended can result in the pond not being aerated properly or the pond freezing solid. Inspect the electrical system to make sure nothing obvious is tripping the system. If you're skilled, replace the GFCI box. Otherwise, have a certified electrician check out the problem.
Fish are gulping for air at the surface
This is an emergency that requires immediate action. Something has changed so that the water doesn’t have enough oxygen. With a hose, spray water hard into a portion of the pond to aerate it. Then make sure the pump and filters are running properly and are not clogged. and the filters are, too. You can also install an aerator.
The fountain or waterfall sound is annoying rather than pleasant.
Try adjusting any valve on the pump to alter the flow. If you have a fountainhead, try a different style of fountainhead, or raising or lowering the extender so it’s higher or lower. With a waterfall, adjust the rocks or add or subtract rocks to alter the sound of the water.
Fish knock over plants in pots.
Support the pots by surrounding them with small rocks and boulders or bricks. If they're on a narrow marginal shelf, consider moving them to a slightly deeper portion of the pond and setting them on a black plastic crate or similar support.
String algae is a problem.
Pull it off or use a UV filter or algaecide, being sure to follow package directions exactly.
The water is green.
Nearly all water gardens have at least a slight greenish cast from floating algae. However, if the water is becoming so green it's murky, consider an additional filter or more plants.
The water smells foul or dank.
It's likely the aeration and filtration system is not adequate or isn't working properly. Clean out your filter or filters. If that doesn’t take care of the problem in a couple of days, consider adding another type of filter for better water quality. Also consider more plants. They naturally shade and purify the water for better water quality.
The pump or filter frequently clogs.
All filters need to be periodically cleaned. With a skimmer, this could be daily in certain conditions, such as when autumn leaves are falling. But if you are having to clean your filter more than every few days, something is out of balance. Consider additional filters for your water garden.
