Leaking Ponds, Filters or Hose. How Do I Locate Pond Water Leak?
QUESTION ... During the brief spell of freezing weather before Christmas I turned off the submersible pump in the pond that feeds a biological filter. Last week, as it seemed to be getting warmer I cleaned out the pump and filter and turned the system on. Since then the water level in the pond has been falling by over 5cm a day despite all the rain weve been having. It must be the filter or the hose that is leaking. Is it likely that the hose split during the icy weather?
ANSWER ... This is what is likely to be the order of probability for your problem.
What is most likely is that the process of cleaning out the filter system has left you with a leak from a fitting. My most common problem with the filter design that I have is that the pump, with its new vigour from a could thorough service and clean out, pushes water up into the filter like it never has done before. The resulting spray that ricochets around the inside of the box, hits the lid and finds it way to drip down the sides. This excessive performance tempers itself after a few days but in the meanwhile you can baffle the force of the jet with some mesh, strategically placed strips of plastic or flat stones. The new extra force of water from the pump may also be finding its way through fitting unions and hose tail joints where it never managed before.
Not only that, the variation in temperature that we have in this country plays havoc with the elasticity of plastic. Aging plastic hose and expanding jubilee clips make for unreliable joints at hose tail unions on the filter box. Some of the cheaper spiral flexi-hoses dont seem to be able to maintain the same seal once the joint has be disturbed, and so the hose has to be cut further back to rejoin to the hose tail. Waterproof grease or Vaseline on the hose tail and grease on the jubilees will help seal the joint and make for easier maintenance in the future.
The thread on the hose tails will often show signs of wear after being loosened for the first time in its life. It is always best to ensure a perfect seal by wrapping all hose tail threads in plumbers PTFE tape.
Now you can check the hose. It is more likely to have been punctured where someone was digging rather than split by the freezing weather, so check where people may have been digging with a fork or spade. Wildlife can be a problem too, though rarely. Mole or badger activity would be the last consideration but bring it up in the order of probability if there is a lot wildlife activity elsewhere in the garden.