Here is a conversation that was had between a customer and our service manager and thought we should share with everyone!
I have iron staining on my pool liner. In the past I have used citric acid and then a sequestering agent, however I have really had wonderful results in the past with ferris tabs. Unfortunately I neglected the pool this winter, hence the stains. My question is how to use the ferri-tabs after using the citric acid? Do I do it immediately afterward? What about the ph level and chlorine level? The chlorine level will be down to nothing and your directions on Ferri-tabs state there should be a measurable amount of chlorine. Any recommendations you have would be appreciated.
FerriTabs I have found work super in just about any conditions. I would treat the stain and apply FerriTabs immediately after. Once the stain lifts from the surface it is back in the water and the FerriTabs can start doing their job right away. I have not personally experienced any issues with using them in 0 chlorine situations vs. high chlorine situations. I just plan on repeating the backwashing and tab addition several times. I usually add 1-3 tablets, backwash after 24 hours, and repeat with 1-2 tablets depending on how dirty the backwash water was.
