My pool was put in late summer of 07. Up until last summer, the skimmer closest to the pump has pulled a little harder than the other one. Late last summer that seemed to change. The closest skimmer also went all summer without a weir. I don't think that's relevant, but wanted to mention it. This closest skimmer is sucking much less than the other one now. If you had lots of leaves in the pool, you'd probably have an 80/20 or 90/10 split on where the trash wound up. I want to also mention that I've had iron staining issues over the years. This March I did an ascorbic acid treatment like I usually do. The skimmer baskets were mostly clean. The basket on the skimmer in question is now deep rust colored, while the other one is still clean. I did vacuum the pool the other day and this skimmer did work with the vacuum hose on it. Still, it sure seams that there is some sort of obstruction and one that is likely ferrous.
How do I go about investigating obstructions when none are visible? Do you merely get an electrical fish tape or plumbing clog line and snake it through or is there something more invasive that is typically done?
Thanks a bunch.