Hey Andy. You will likely get more responses on the United Kingdom version of this forum. They seem to have more over there than we do here, but I'll give a try to a few possibilities. You don't say how the clay was compacted or if any Montmillorite (Bentonite) clay was used. If there was an inclusion (a different type of soil or roots) that could easily be where the leak is located. We just had a discussion about puddling clay on this forum a few weeks ago for a pond and much info came from sites about Dew ponds in the U.K. One of the most common locations for leaks was the top edge of the pond which could act as a wick if it was not constructed properly. I never had much luck with using dyes in the water to find a leak. It mixed much too quickly. One material I have found useful was a handful of fine, dry, powdered clay scattered on the surface. Calcium Bentonite is quite good for this since it can be purchased as a fish tonic or cosmetic base as well as a construction material. If the water is reasonably clear it should work well for you. If not, it needs rethinking. Some one suggested dry milk powder to me. I didn't try it but it sounded reasonable and would be inexpensive. The Bentonite should be available at home and garden supply stores or through a well digger, which is where I found it. The added advantage is that the Bentonite can be used to seal the leak when you find it. Check on this forum for the Puddling Clay thread and do a search for Dew ponds, one of which is linked in the puddling thread. Sandy Here is a link that might be useful: Puddling clay

Martjane43, This is an interesting situation. I have a couple of different thoughts but none of them make much sense. The first is that when it gets cold outside the water becomes ice and expands. But even if the pond froze solid it would not expand enough to go from half full to totally full. The other is that when it gets cold the ground water under the pond rises. The only way that this would make sense is that you have a drainage line that freezes up and doesn't allow the ground water to drain out and it rises in the ground pushing the water up in the pond. If this is not what is happening then to have a better idea what is happening I need more information. First is how big is the pond and how deep? The more important information is what else happens when the weather gets cold. Does it rain when it gets cold and dry out when it gets warm? Mike

No, level 4 is not "better" than level 1. It will filter smaller particles at the expense of higher pressure drop. You use the lowest level that will remove the particulates in your water. Using a filter that is too fine will just impede water flow for no reason. Typically, 25 micron is a good place to start. 5 micron is really small, so avoid it unless it is absolutely necessary. The filter should be upstream from your softener. If it is downstream, it is doing you no good -- don't bother placing a filter cartridge in it.

I will try and post a pic tomorrow. We had shut off the water fall and it made no difference. It seems to me that the water level drops because the water outlet or intake into the filter is set so low into the side of the pond. The water runs out to that level and then stops. We tried blocking it partly up today with some success. I am at work now but I will check it when I get home. We are in the Black Hills of South Dakota.