Back flushing every couple of days

Jul 10, 2015
19
Dearborn,MI
Hello,

First, I want to thank this forum for the excellent advice and knowledge it has to offer. My pool water is crystal clear and very well balanced by following the procedures on this forum.

However, I am currently having to back flush way to often. After back flushing my sand filter will read 13-13.5 PSI. My pump is approximately 10-12 feet away but with how the 1 1/2" pipe runs the total length would be about 16 linear feet from skimmer to pump. When the PSI gets up 14.5-15 PSI I can tell a huge difference in flow from my return. At this PSI my Hayward above ground pool heater will stop running due to my GPM falling below 20 GPM. At this point the heaters pressure switch will activate. Back flushing returns pool to normal operation and the heater will work fine.

A little info in regards to pool:

13,000 gallons above ground pool that is buried 2 feet in ground. The pool has a deep end of 6 feet. The pump is 1 hp and is approximately 1 foot below the skimmer. All piping is 1 1/2" schedule 40 PVC.

What could be causing this?

I'm thinking that my pump might not be powerful enough based off the design of my pool?

This is a Doughboy pool which they sell as a kit so I assume the 1 hp pump would be more than enough for a standard build. ( not being buried and 6 ft deep) The pool store has offered no help but to back flush for longer periods of time.... this does very little if anything.

I have no sand coming out of the return and almost always my pool water is clear coming out of my back flush pipe. The heater is a new addition this year and last year I don't recall having to back flush as frequently but still noticed a difference in flow within a couple PSI.

Any help and guidance would be great, I look forward to the responses.

Thanks

Greg
 
Maybe slightly when the FC gets to around 1 PPM. When bringing FC back up to 5 ppm in all honesty it looks pretty clear. The slight cloudiness I do have I assumed it was caused by high bather load at lower FC levels. (Still dialing in CYA)

- - - Updated - - -

I do have to vacuum up a lot of regular sand each week due to the fact a paver patio is getting installed around my pool and when I dug it out I had a lot of playsand. Washing off feet helps but sand still gets into pool.

Could this sand be affecting my filter flow rate?
 
What could be causing this?
Probably 3-4 posts each day on this subject. Your filter is doing exactly as you asked, it is catching debris and filtering it from your pool. The filter gets clogged and you have to backwash it.

What is clogging it? Algae, 9 times out of 10. You have a chemistry problem and you will need to SLAM the pool to clear the algae and then your filter will operate normally.

This is a bit unrelated but you need a new filter gauge. There is no way a 1 - 1.5 psi increase can almost stop your flow. Get a good gauge.....it's an important part of pool management.
 
I have replaced the gauge with one that is filled with glycerin and the results are the same and flow is restricted at the same PSI which is 1-1.5 PSI. With 2 different gauges and the same reading its safe to assume that there no problem with my gauges.

Here is my most recent levels yesterday evening:

FC: 3
CC: 0
CH: 150
TA: 180
PH: 7.7 (in between 7.6 and 7.8)
CYA: under 30 now due to high amount of backflushing:

My water looks clear except as mentioned when FC gets low and I have high bather load. My numbers sure do not indicate that there is an algae bloom! I did have a problem at the beginning of this season with organic matter and had to slam my pool (pool was just eating up all the chlorine I good feed it). Should I have did a deep clean of my filter after the slam?
 
What you have is a nascent algae bloom. You have just enough FC to keep ahead of it but when it drops too low the algae starts to multiply. That is what gives the pool a cloudy appearance. If you let it go a couple more days you would see it start to turn green. You could probably bring it to slam level overnight and take care of the nascent algae, but you have to keep the FC within the recommended range to prevent it from coming back.

It is odd that you would see restricted flow with such a slight change in pressure. I don't know if deep cleaning the sand is the answer, but it couldn't hurt.
 
I have replaced the gauge with one that is filled with glycerin and the results are the same and flow is restricted at the same PSI which is 1-1.5 PSI. With 2 different gauges and the same reading its safe to assume that there no problem with my gauges.
We didn't know that...Thank you.

It still makes no sense, however, unless (as you suspect) your filter is just clogged full of debris that the backwash is not removing. In that case, it will be helpful to remove the top and do a deep cleaning.

If your psi (clean) drops down to about 6-8, that would tell us you fixed it.

It would not stop your filter from clogging but it would spread out the interval.
 
As mentioned, the number one reason for a quickly clogging filter is algae. Early signs of algae is low FC, below min, and cloudy. Then clogging filter and slightly slimy pool walls, then a little green on the side and then green water. We TFPers tend to catch it early because because we are paying attention to our filters and our FC levels. Anyway, no need to guess, simply run an Overnight Chlorine Loss Test and you will know for sure.
 

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Thanks again for the reply... There was a lot of junk... 2 grocery bags full on top of the sand. I flushed it out per videos here on this forum. Maybe helped .5 PSI running 13 PSI..

Going to start the slamming procedure right now... Thanks for all the advice! Will let everyone know the results.

Thanks
 
I was very surprised to see that much junk sitting on top of the sand. Glad that I did it!! I will definitely be including that in my opening/closing procedure.

Ran a complete test, the numbers are a little different from last night is that caused by me deep cleaning the filter?

FC: 15 (currently slamming)
CC: 0
PH: 7.7
CH: 230 (climbed 80ppm overnight)
TA: 150 ( dropped 30ppm overnight)
CYA: less than 30 ( I had it up to 40ppm last week, added water, heavy bather load and lots of back flushing)
Saturation index: .4

Should I add more stabilizer now or wait until I pass the overnight test?

Again thanks for the advice.... This forum is great!!
 
I have a lot of play sand currently around the pool from excavation. A lot of this sand gets in the pool from feet which are washed but some still get in. The junk which was really play sand and fine debris particles clumped together. There was nothing larger that could have passed through the skimmer or pump screen.
 
FC this morning was at 9 lost 2 ppm overnight, filter PSI was 15 and a noticeable difference in flow at return. Seems I still have some type of containment's.

Brought FC back up to 12 will check again early afternoon.

Why such a noticeable difference in flow at 1-1.5 PSI? At this current pressure my heater will not function. After doing a deep clean and a back flush I was at the same PSI I started with 13 - 13.5 PSI is this all caused by algae?

I agree I have some containment's but this couple PSI flow restriction I'm not understanding? Could my pump be to small for my pool build?

Thanks
 
Yes, I watched a few videos on this forum that showed how to do it. I stuck the hose up and down through out the entire filter until water was clear when overflowing. I had the same high filter pressure last year but didn't really notice to much because I didn't have a heater. With the heater installed @ 15 PSI filter pressure, the heaters pressure switch will trip and will not run. 13.5 PSI after back flush heater works.
 

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