Filter and pump sizing issue?

TazJMT

Well-known member
Jun 19, 2014
97
Spotswood, NJ
Re posting with new information:

Hello All,

Long post, here is the short version: I am concerned that my pump is too strong for my sand filter. I have a 10K gallon pool. Please see the pics for the specs. I do not know enough about the math to know if they are ok together.

Longer version as to what I am seeing:
End of the pool season 2016 we are having our first child and my mom is at our house and calls me to tell me our old pump crapped out. I run home, buy a new pump/filter from the store (old one was from previous home owners) and run back to the hospital. Hayward S166TPAKS sand filter, Hayward Power-Flo LX 1.0 HP pump SP 1580 TLFP

Mid way through the next season (2017) and all of 2018, I am seeing something in the pool that might be sand but I am not sure. It only happens when the pump is running. When I brush it, it dissipates, but that could be algae too. I do the "sock test" with cut piece of a red stocking/legging from my wife and put it over the return for approx 4 hours to see if it catches any sand. Then I check it out and I think I saw a grain or 2 of sand but that's it. So I say to myself "The amount of stuff I am seeing in the pool cannot be coming from a couple grains per day, so it must be algae". So I throw all kinds of chemicals at it. No change, but the pool seems fine otherwise, so I just vacuum more often that normal.

This year, I had an ammonia problem when opening the pool. I SLAMed the pool. Hard. From this forum, I understand more now and know that the pool looks perfect and I do not lose any chlorine overnight, and all my levels are great, so it can't be algae. Then I happen to start researching the size of my filter vs. my filter. I am not sure about the specs, so I posted them in the pics below and am hoping that someone can tell me if my pump is too strong, then I know it is sand. That is my suspicion, but I am unsure

1st 2 pictures show flow rate specs for filter and pump, last picture shows a bit of what accumulates after pool is vacuumed and then pump ran for a couple hours
 

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anotherpyr

Well-known member
Jun 22, 2007
90
Columbia, MD

TazJMT

Well-known member
Jun 19, 2014
97
Spotswood, NJ
So I’m guessing the filter is an S166T based on the effective filtration area. Pro-Series | Filters | Above Ground Pool Filters - Hayward Pool Products

Power Flow LX Power-Flo LX | Pumps | Above Ground Pool Pumps - Hayward Pool Products

I posted the links so that someone more knowledgeable could consult the specs for them assuming that’s the right filter.

Out of curiosity what was the original pump?
Yes that is the filter, I was told to add it to my signature line so I did. I will add it to the original post

The original pump-i dont remember exactly-i know it was a hayward power flo but i think it was less HP because it comes out of the return way harder now
 

anotherpyr

Well-known member
Jun 22, 2007
90
Columbia, MD
Looking at the power flow II specs, the LX pumps put out much more gpm at the various levels of feet of head. Example: At 40 feet of head the LX puts out 58 gpm and the II puts out 40 gpm with the 1hp pumps.
 

duraleigh

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Apr 1, 2007
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I am seeing something in the pool that might be sand but I am not sure
I'd like to go back to your first post and address if it is sand or not.

First off, it usually isn't. Tell us if you can capture the gritty grains of sand between your thumb and forefinger or does it just poof away?

On the filter/pump sizing, your filter appears a little bit small for the pump but I would sure like to confirm you have sand on your pool floor first.
 

TazJMT

Well-known member
Jun 19, 2014
97
Spotswood, NJ
I'd like to go back to your first post and address if it is sand or not.

First off, it usually isn't. Tell us if you can capture the gritty grains of sand between your thumb and forefinger or does it just poof away?

On the filter/pump sizing, your filter appears a little bit small for the pump but I would sure like to confirm you have sand on your pool floor first.
Ok I will give that a try and report back shortly-makes sense to test I just can't imagine it is organic if my levels are all good and water is crystal
 

TazJMT

Well-known member
Jun 19, 2014
97
Spotswood, NJ
I'd like to go back to your first post and address if it is sand or not.

First off, it usually isn't. Tell us if you can capture the gritty grains of sand between your thumb and forefinger or does it just poof away?

On the filter/pump sizing, your filter appears a little bit small for the pump but I would sure like to confirm you have sand on your pool floor first.
Ok, well I am surprised. One answer brings many questions. I could not feel any grit and check like 12 different spots. It poofed away every time.

So, that requires more background: In 2017, the filter was 11 months old and I took it back to the store complaining of this-they checked the head/valve ports and found some small imperfection that let them warranty it and give me a new multi valve port and stand pipe/flange finger things. Of course, I also changed the sand since it was out anyway. Problem obviously persisted.

Levels are all good, water looks amazing. Issue only happens when filter runs

So I have no idea what this stuff is.

If it matters: a hose comes off of my skimmer to the pump, another hose from pump to filter, and hard pvc from filter to chlorinator and finally hard pvc from chlorinator to pool. A few threaded unions along the way. (i don't use the chlorinator anymore, but didn't want to change the entire system to pull it out)
 

duraleigh

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So I have no idea what this stuff is.
It's dead algae. That is a chemistry problem and has little, if anything, to do with your filter.

You only see it when your pump is running because the water flowing across the pool floor piles it up in tiny divots and depressions.....often along seams in the vinyl.

To get rid of it, you must SLAM the pool correctly and maintain a constant adequate level of chlorine to keep it from appearing in your pool. You indicate you have SLAMmed your pool before but I hope you will re-read the SLAM process and follow it in EVERY detail.

Start by posting a complete set of tests from the best test kit there is......the TF-100, and we'll help get your pool crystal clear.

I want to emphasize that your filter is not the issue.......chemistry is the issue.
 

anotherpyr

Well-known member
Jun 22, 2007
90
Columbia, MD
Pumps are about flow rate against a given resistance. In comparing the 2 pump models, the LX appears to be more efficient getting higher gallons per minute with the same hp motor.

Hayward sells this filter in a pump and filter combo with the 1.5 hp Power Flo LX pump. The 1.5 hp version produces about 5 more GPM than the 1 hp at each feet of head value in the table. So the filter should be able to handle the 1 hp pump.
 

TazJMT

Well-known member
Jun 19, 2014
97
Spotswood, NJ
It's dead algae. That is a chemistry problem and has little, if anything, to do with your filter.

You only see it when your pump is running because the water flowing across the pool floor piles it up in tiny divots and depressions.....often along seams in the vinyl.

To get rid of it, you must SLAM the pool correctly and maintain a constant adequate level of chlorine to keep it from appearing in your pool. You indicate you have SLAMmed your pool before but I hope you will re-read the SLAM process and follow it in EVERY detail.

Start by posting a complete set of tests from the best test kit there is......the TF-100, and we'll help get your pool crystal clear.

I want to emphasize that your filter is not the issue.......chemistry is the issue.
@duraleigh

I can give it a try but I assure you that I followed the SLAM process in every detail and every night I bring the FC up to 5.5 (my CYA is between 30-40)

I asked A TON of questions earlier this year in this thread (below) as i had a terrible combined chlorine problem that ended up being ammonia. A good test kit (TF100) and 15 gal of bleach later and the pool looks better than it ever has. I will go do a test and post the results here, but when i did the SLAM i passed the overnight test easily.
 

TazJMT

Well-known member
Jun 19, 2014
97
Spotswood, NJ
Pumps are about flow rate against a given resistance. In comparing the 2 pump models, the LX appears to be more efficient getting higher gallons per minute with the same hp motor.

Hayward sells this filter in a pump and filter combo with the 1.5 hp Power Flo LX pump. The 1.5 hp version produces about 5 more GPM than the 1 hp at each feet of head value in the table. So the filter should be able to handle the 1 hp pump.
@anotherpyr

thanks for this-is there some formula I can follow to do the math to know how much flow rate the pump is above the filter? As I look at it, the pump is 60GPM and the filter is 25 GPM/FT2. So if I divide the 25 by 1.4, I am of course way under the 60 on the pump
 

skimmerswimmer

Well-known member
Jul 30, 2013
357
Long Island, NY
@duraleigh

I can give it a try but I assure you that I followed the SLAM process in every detail and every night I bring the FC up to 5.5 (my CYA is between 30-40)
Bringing FC up to 5.5...from what? You may want to overshoot your FC/CYA target range by a few ppm if you are only adding once per day and see if anything changes. Also, for a SLAM with 40 CYA, you want to keep FC at 16 ppm.
 

TazJMT

Well-known member
Jun 19, 2014
97
Spotswood, NJ
Bringing FC up to 5.5...from what? You may want to overshoot your FC/CYA target range by a few ppm if you are only adding once per day and see if anything changes. Also, for a SLAM with 40 CYA, you want to keep FC at 16 ppm.
around 2.5. I was under the impression that adding about 3ppm per day was normal on sunny days
 

TazJMT

Well-known member
Jun 19, 2014
97
Spotswood, NJ
@duraleigh

got these results minutes ago:

FC 3.0
CC-.5 (I think more like .25, i have seen this test get way pinker and still go clear on 1 drop)
Ph 7.6
TA 110
CH 225
CYA-ugh i guess 40- i hate this test, i am going to SLAM assuming 50 to be safe but i can talk myself into this being 30 or 40 or 50
 

anotherpyr

Well-known member
Jun 22, 2007
90
Columbia, MD
@anotherpyr

thanks for this-is there some formula I can follow to do the math to know how much flow rate the pump is above the filter? As I look at it, the pump is 60GPM and the filter is 25 GPM/FT2. So if I divide the 25 by 1.4, I am of course way under the 60 on the pump
I think you mean 25 x 1.4 = 35 which is on the label as the designed flow rate for the filter.


That’s the most informative post I’ve ever read about figuring it out.

According to the manual, the Power Flo II is meant to sit above the waterline like an in ground pump. So I should’ve compared the LX to the Matrix. They have identical tables.
 
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TazJMT

Well-known member
Jun 19, 2014
97
Spotswood, NJ
I think you mean 25 x 1.4 = 35 which is on the label as the designed flow rate for the filter.


That’s the most informative post I’ve ever read about figuring it out.
Oh-yeah 25x1.4 is 35 but the way it says it on the label, it is GPM/FT2 which i always knew to mean divided by

if it is as simple as 35GPM flow rate filter and 60GPM pump, that seems like the pump is too big, no?
 

TazJMT

Well-known member
Jun 19, 2014
97
Spotswood, NJ
Surprising result. SLAMed the pool to 20 FC (from 3, added 17 with 1 gal, 1 qt, 2 cups). Checked an hour and a half later, was down to 16.5. Doing this after dark (how do people SLAM in the daylight and account for the light eating the FC?). Just added 3.5 more, going to check in an hour or so before bed.

Stunned it lost anything. Every day it was losing about 3 and water was clear, that did not stir up any suspicions on my part

As i said, i am SLAMing for a 50 CYA even though i am pretty sure i am lower than that-but i assume i can go as high as i want with FC at night-even if i put 100 FC in it (i won't) it shouldnt lose any at night, right?