You may not be getting a response because you seem to have listed a merchant (ADS) rather than a type of pipe, and because you have not provided many details of what you are wanting. I am guessing the installation will cost much more than the actual pipe, but I do not have standpipes on my 3 fish ponds. I do have small standpipes on 3 of my wetlands, but your pipes are much larger than those. Seems like you options are to replace what you have or to block it off and add a new system (which might be less costly). A lot of folks here favor siphon systems. I like the simplicity of a straight pipe with a shroud to prevent vortexing, and a sturdy drain guard. I use PVC sewer pipe rather than the less expensive double-wall plastic, but I tend to over-engineer things.