What's blocking my flow?

[keep-it-simple]

Just when I think I'm starting to understand the pool basics...

About 2 weeks ago I determined through playing around that I could set the filter as low as 2175rpm as have the swg operate. It needed to be no lower than 2700rpm for the swg to work while the automatic vacuum was running.

In the process of troubleshooting possible leak around the skimmer.... Hopefully will have that figured out by early next week.
I've been running the filter using the bottom drain only for intake. The FC was dropping so I bumped up the swg. It rained today so I switched the pump to half skimmer and half bottom drain. I noticed the swg indicates no flow.
I played around with the settings and now using any combination of skimmer and/or bottom drain, the minimum rpm for the swg to work is 3400.

Any ideas of where I should begin troubleshooting? The flow is visibly minimal. I don't think it's a bad sensor in the swg.

 

[Richard320]

What's the filter pressure? The RPM tells you how fast the pump is spinning, but not really how hard it's working. You might be clogging the filter with the beginnings of an algae outbreak since you're losing FC faster than usual.

 

[keep-it-simple]

I think I'm losing FC because the swg hasn't been on... :-/
PSI on the filter is up to almost 10. I've been backwashing every day - every other day when it gets up to 18-20PSI (GA pollen!), which drops it down to about 3PSI. I'd prefer not to backwash at the moment because my son was "helping" and dumped approx 2lbs CYA in the skimmer - so I don't know how long it will take for that to dissolve. He says he poured it slowly. Could that solidify somewhere and clog the entire line?

 

[Richard320]

I think I'm losing FC because the swg hasn't been on... :-/
PSI on the filter is up to almost 10. I've been backwashing every day - every other day when it gets up to 18-20PSI (GA pollen!), which drops it down to about 3PSI. I'd prefer not to backwash at the moment because my son was "helping" and dumped approx 2lbs CYA in the skimmer - so I don't know how long it will take for that to dissolve. He says he poured it slowly. Could that solidify somewhere and clog the entire line?

Yes. But it would clog the intake side, which would lower flow and pressure. That's why we recommend the sock method. And you don't lose it if you need to backwash. Do you have a clear strainer lid - that's the basket hooked to the pump - and do you see a lot of air in it? Any chance it's packed full of leaves?

 

[keep-it-simple]

All baskets clean and empty. Water flowing through with little to no air bubbles.
Pool is crystal clear and clean.
Last full test showed everything in balance except CYA was still a little low.
20-Apr
FC 5
TC 5
CC 0
pH 7.2
TA 90
CH 120
CYA 40
salt 3800

I added 5lbs CYA after that reading - all dissolved within about 4 hours. TC via OTO this morning was maybe 3-4 and pH was up to 7.4. My son added about 2lbs CYA this afternoon.
It rained maybe 1/2" today and the kids played with the hose around the pool for maybe 20 min tonight, so I'm sure I'll have some more TA work to do to get it down to 70-80ppm.

 

[Bama Rambler]

So it's been 5 days since you've ran the CYA test?
Have you (and/or someone else) added 7 lbs or 9 lbs of CYA?
What speed do you use to determine when to backwash? You should pick a speed, say 2700 rpm and record the pressure at that speed just after a cleaning and then always go back to that speed to determine when to backwash.

If it's been 5 days since you've added any CYA I'd say that you cna backwash without fear of losing much of it.

 

[keep-it-simple]

So it's been 5 days since you've ran the CYA test?

Correct.

Have you (and/or someone else) added 7 lbs or 9 lbs of CYA?

Yes, 5lbs added Saturday and approximately 2lbs added yesterday before my post.

You should pick a speed, say 2700 rpm and record the pressure at that speed just after a cleaning and then always go back to that speed to determine when to backwash.

Thanks for the tip! I've checked it each time at 2175rpm by pure accident. I'll be sure to keep this in mind.

 

[Bama Rambler]

So you started out with a CYA of 40 ppm and have added 9 lbs to that?

If that's so, then you have a CYA of ±80 ppm.

 

[keep-it-simple]

5lbs Saturday plus approx 2lbs CYA Tuesday = 7lbs added since last reading.
5lbs dissolved within several hours
2lbs poured into skimmer so I don't know whether it has dissolved.
I'll do a full test later this afternoon/evening. Is the CYA level significant to the reduced flow rate?

 

[Bama Rambler]

Probably not, I was more interested in the length of time so you could backwash and see if that helps?

 

[keep-it-simple]

Oh, okay, thanks! I was worried I was going to have to start over again with CYA and that stuff is expensive!