tetra has been around for years, and they stand behind there products. If you haven't tried there food the fish love them. i don't know that they are the best food on the market but by far good enough to maintain most fish in a pond and keep them healthy. As for the sludge tablets, give them a try! All it is is beneficial bacteria that actively eat away at sludge and breakdown. More and more companies are coming out with sludge reducers and even at the Koi shows they now have products that can be directly sprayed on food that start helping the process from internal to the filter. robiotic is new but it's basically the same thing except it starts inside the fish to help remove waste and benefit immune systems in the fish themselves. I'm glad to hear they replaced the pump. That just goes to show the upstanding service that tetra takes to make their customers happy and repeat customers.