Hello! Pool suction randomly dropped from 40 GPM to 25, and I can’t figure out why. Quad 80 DE filter started at 11 PSI and is only showing 13 now. I cleaned it in on May 25 but wouldn’t it gradually go down, not a rapid drop? It was humming at 40 a couple of days ago and it started at 42 GPM. Both skimmer and poolside cleaner suction are the same, no difference when I change it. It is easy to see on the return, as the spillway is just trickling when I run that. We do have little kids with little toys - might there be a clog? Baskets are clear. Help! Thanks!
Rapid drop in suction flow, can’t figure out why!
- Thread starter benpcoleman
- Start date
- Feb 6, 2015
- 7,819
- Pool Size
- 12300
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Post a full set of current test results (your PoolMath shows a full set from 3 months ago).
Also do an Overnight Chlorine Loss Test to rule out any chemistry issues.
Can you ramp the pump up to provide the 40 GPM?
I'm not a big fan of setting the pump for a specific GPM or percentage. I'd rather set a specifc RPM and then check return flow and filter pressure to determine if the system is running how I expect it to.
Also do an Overnight Chlorine Loss Test to rule out any chemistry issues.
Can you ramp the pump up to provide the 40 GPM?
I'm not a big fan of setting the pump for a specific GPM or percentage. I'd rather set a specifc RPM and then check return flow and filter pressure to determine if the system is running how I expect it to.
- Jun 24, 2021
- 16,239
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
Your pool math logs do not show CYA since may.
Your FC got down to 2.5.
You likely have organics/algae, even if you cant see it.
Post a full set of test results.
Perform this test tonight. Link-->Overnight Chlorine Loss Test
You fail, follow the SLAM process. Link-->SLAM Process
Your FC got down to 2.5.
You likely have organics/algae, even if you cant see it.
Post a full set of test results.
Perform this test tonight. Link-->Overnight Chlorine Loss Test
You fail, follow the SLAM process. Link-->SLAM Process
Thanks-this is a great start. I’ve kept chlorine in the 5-9 range so easily, but yes it did drop to 2.5 very briefly then back up. Water is super clear and I had 4ppm and 0.0 CC yesterday. Feels like that is a big drop for algae but I’ll definitely give it a go.
I have never changed RPM from the set up when pool was built last summer. So I just check GpM to see how it is performing. Is that a good way to go? If I need to SLAM I will definitely ramp it up.
Yes, CYA hasn’t been tested. Didn’t think this moves much?
Thanks yall!
I have never changed RPM from the set up when pool was built last summer. So I just check GpM to see how it is performing. Is that a good way to go? If I need to SLAM I will definitely ramp it up.
Yes, CYA hasn’t been tested. Didn’t think this moves much?
Thanks yall!
- Feb 6, 2015
- 7,819
- Pool Size
- 12300
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Post a full set of current test results.
Do an Overnight Chlorine Loss Test.
CYA doesn't change much if you aren't adding any. But it does degrade a bit, especially in hotter temps.
In summer here in AZ, I can easily see a 10 ppm drop in CYA in a months time.
CYA should be tested monthly or more often if you are having issues maintaining FC.
At a given RPM, flow (GPM) will reduce as the filter gets dirty.
Do an Overnight Chlorine Loss Test.
CYA doesn't change much if you aren't adding any. But it does degrade a bit, especially in hotter temps.
In summer here in AZ, I can easily see a 10 ppm drop in CYA in a months time.
CYA should be tested monthly or more often if you are having issues maintaining FC.
At a given RPM, flow (GPM) will reduce as the filter gets dirty.
- Jun 24, 2021
- 16,239
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
Filtering at lower speeds is better.
Test your CYA. In Escondido, you might lose up to 15ppm per month if your water is north of 90.
You guys weren’t kidding. Tested at CYN at 40 today. Okay, new set of results are up. Wasn’t able to do overnight test but will tonight and will report back.
Okay, I passed the overnight test. No chlorine loss.
As I write this, my pump has slightly gone back up to 32 GPM at the same RPM. My FC has ticked up to 6.5 after running super chlorination yesterday. However, when I turn on the spillway, it still barely trickles which demonstrates the reduced flow. (All of this is at the exact RPMs I’ve always been using)
Checked impeller and nothing stuck. At this point I’m guessing it is just a dirty filter? But what would explain the rapid drop?
As I write this, my pump has slightly gone back up to 32 GPM at the same RPM. My FC has ticked up to 6.5 after running super chlorination yesterday. However, when I turn on the spillway, it still barely trickles which demonstrates the reduced flow. (All of this is at the exact RPMs I’ve always been using)
Checked impeller and nothing stuck. At this point I’m guessing it is just a dirty filter? But what would explain the rapid drop?