I just got an i-Tech skimmer 100 that is used but have a question about it from all that have or do use them. The neck seems to be missing a gasket or does the top just sit on there without a gasket in the neck? If it does require one where can you get one for them? I am ready to swap out my PM skimmer for the i-Tech but need to make sure it is ready to go but cannot find any info on them on the web anywhere but in forums talking aobut how good they are. That is all good and fine but would like an overview of it and the parts that is has to make it work.