Hi, sorry you've not been getting any replies. We do answer questions, although I can see you've not had much luck in getting replies to your questions so far. Obviously we can only answer questions we know the answers to, and not everyone here will be able to help you. I for one can't really answer any of the questions you've posted (ponds aren't my area). Maybe nobody else who knows the answer has been on yet, and in the case of your older posts they may have been pushed down the list and may therefore have been missed by the people who have the answers - I hadn't seen some of them myself until now and I'm on here most days. The only help I can maybe offer is in response to your questions about dechlorinator. In my tank I only use enough dechlorinator for the water I'm adding, and I add the dechlorinator to the fresh water BEFORE adding it to the tank. If you don't dechlorinate the fresh water before adding then I would think you would need to treat the full volume, but I would never do it that way anyway. But that's for a tank. For a pond I would guess the same would probably apply, but I honestly don't know. Not sure of the size of water changes you need to do on a pond, but I would guess we're talking pretty large volumes of water so dechlorinating before adding may not be practical.