After backwashing my sand filter, and typically add 1 cup of DE. I don't see an immediate pressure rise, and the pressure will typically rise slowly over time.
However, occasionally I experience an odd phenomenon. When the pump is running at the low skim speed (2000 RPM), the pressure will start to climb and the flow rate at the returns will noticeably decrease. I have a fountain, so this effect is very noticeable and measurable.
If I run the RPMs up to the service speed (2750), the pressure isn't unusually high for that speed. Then, if I stop and then restart the pump and wait for it to resume at 2000 RPMs, the pressure will be back to normal, and the fountain height will be restored.
Is there any logical explanation for this? The pool water is quite clear. I do get some daily debris from trees, and there may be a correlation with the time that I brush the pool (although it would be a delayed effect). This issue has caused me to erroneously backwash the filter when it has been less than a week from the previous backwash. I don't experience any of this when I'm not employing DE. I hypothesize this is some sort of sand filter channeling issue, however I deep cleaned it just last season.
However, occasionally I experience an odd phenomenon. When the pump is running at the low skim speed (2000 RPM), the pressure will start to climb and the flow rate at the returns will noticeably decrease. I have a fountain, so this effect is very noticeable and measurable.
If I run the RPMs up to the service speed (2750), the pressure isn't unusually high for that speed. Then, if I stop and then restart the pump and wait for it to resume at 2000 RPMs, the pressure will be back to normal, and the fountain height will be restored.
Is there any logical explanation for this? The pool water is quite clear. I do get some daily debris from trees, and there may be a correlation with the time that I brush the pool (although it would be a delayed effect). This issue has caused me to erroneously backwash the filter when it has been less than a week from the previous backwash. I don't experience any of this when I'm not employing DE. I hypothesize this is some sort of sand filter channeling issue, however I deep cleaned it just last season.
