How can you tell if your sand filter is low on sand?

germangirl

Member
Aug 11, 2011
14
Hello everyone,

I opened my sand filter up for the first time after four years of having it, to do a deep clean. The sand looked very clean to begin with and rinsing didn't really wash up anything either so I guess we are ok.
However, the level of sand is what I would describe as a little less than half full. Is that normal? I never looked into one before so I have no idea what it should look like and was wondering if we lost sand over the years?
If so, can I buy a bag and just top it off?

Thank you
And a sparkling pool season to all
 

JasonLion

TFP Expert
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May 7, 2007
37,880
Silver Spring, MD
Some sand filters have a fill line inside showing where the sand should come up to. Typically the filter is just a little less than half full of sand, there needs to be room on top for water circulation.
 

germangirl

Member
Aug 11, 2011
14
Wow,
I swear this is the friendliest forum ever. I am never embarrassed to ask questions, and the people on here always know the answer.
Thank you so much for the quick reply
 

jblizzle

Mod Squad
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May 19, 2010
42,327
Tucson, AZ
Some sand filters have a fill line inside showing where the sand should come up to. Typically the filter is just a little less than half full of sand, there needs to be room on top for water circulation.
Here is a quote from page 3 in the manual for your filter:
Hmm. These seem to be a bit contradictory.
I would have though you want the sand up at the top of the largest diameter of the filter ... but I have no experience ;)
 

duraleigh

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Apr 1, 2007
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I have always assumed most sand filters do best a little over half full......even around 2/3 full. They certainly need "freeboard" (room at the top) but the more sand the water has to pass through, the better the filtration.
 

Kiss4aFrog

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TFP Guide
May 22, 2013
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Hudson, WI
On Hayward's site the manual says that specific model takes 300lbs #20 silica sand to fill it up. http://www.hayward-pool.com/pdf/manuals/ProSeries-S180T-S210T-S220T-S244T.pdf

I didn't see anything about 6" from the top in that manual. Like mine I think with 300lbs you're going to be somewhere around half full.

They do recommend filling it 1/2 full with water before adding the sand to cushion the laterals from the shock of the falling sand. ;)
 

Propbndr

LifeTime Supporter
Mar 26, 2015
314
Charles City, Va
On Hayward's site the manual says that specific model takes 300lbs #20 silica sand to fill it up. http://www.hayward-pool.com/pdf/manuals/ProSeries-S180T-S210T-S220T-S244T.pdf

I didn't see anything about 6" from the top in that manual. Like mine I think with 300lbs you're going to be somewhere around half full.

They do recommend filling it 1/2 full with water before adding the sand to cushion the laterals from the shock of the falling sand. ;)
Using the link provided, the 6" measurement is found in the Installation section on page 3, step 3 "Loading sand media" sub step D.

In my Triton 2, the "free board" between the top of the sand and filter housing is 10.5". My operating manual stresses the importance of this measurement. From my manual:

NOTE: The free board distance is the most important variable and should be maintained. Sand density will vary and therefore sand amount is given as a reference.
 

Kiss4aFrog

LifeTime Supporter
TFP Guide
May 22, 2013
2,723
Hudson, WI
You are absolutely correct, it does.

d. Carefully pour in correct amount and grade of filter
sand, as specified on Table 1. (Be sure center pipe
remains centered in opening). Sand surface should be
leveled and should come to within 6" of the top of the
filter tank. Remove sand shield from internal pipe.

And Table 1 for that filter says 300lbs. That just seems awfully full but it's what the manual tells you to do.
 

Propbndr

LifeTime Supporter
Mar 26, 2015
314
Charles City, Va
Table 1 for that filter says 300lbs. That just seems awfully full but it's what the manual tells you to do.
I agree, it does seem awfully full. The free board level on my filter is so large because the defuser and inlet piping assembly actually is designed to pivot which, allows for almost full access to the top of the sand bed and to not have to cover the defuser when replacing the sand. This is a great feature!

Her filter does not have the pivot feature so, it does not require a huge free board space. Perhaps, at 6" free board, the design of her filter's body allows for full diameter surface area exposure.
 

germangirl

Member
Aug 11, 2011
14
Ok, so after reading the manual (by the way, great idea guys) one would assume 300 pounds of sand would bring it up to about 6 inches from the top.
If that is true, where did all the sand go? I never really had to backwash too much, like I said the sand looks really clean. The laterals seem fine since there is never any sand backwashing into my pool. I am not taking the sand out just to weigh it, ( even so am tempted) but if I had to take a guess , it would be a loss of at least 75 pounds or so. I grew up metric so this is a so so estimate. But like I said, the filter is less than half full. Can they loose that much sand under normal conditions in about 5 years?
Maybe the pool builder never put in 300 pounds of sand to begin with? But at the same time looking at the size of that filter it looks like it would take more than 300 pounds of sand to bring it within 6 inches of the top. Somehow these two numbers don't really add up?
So I will do what my german heart of precision and regulations tells me not to: I will "kinda guess" and put "some" sand in until it "looks about right".
After that, I will sit by my pool and have a beer, because some stereotypes are not stereotypes at all
:cheers:
 

Propbndr

LifeTime Supporter
Mar 26, 2015
314
Charles City, Va
When I changed my sand, 2 weeks ago, the sand level was down to about half the body level also. So I know your confusion. The only thing I can think of is when backwashing the sand partials grate against each other turning some of it to dust which gets flushed out during backwash. That would explain why no sand gets sent back to the pool and why the level will decrease.
 

Kiss4aFrog

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TFP Guide
May 22, 2013
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Hudson, WI
I guess you'd be safe anywhere from half full to within 6" of the top. Good chance that like a lot of "us" the installer didn't read the manual either and went off what he's been doing in the past. That or he tried to save a couple bucks for his beer that evening ;)

My filter, I'd go by the manual and add some sand to get it closer to that 6". The more sand, the better it should filter.
 

DaneCE

Well-known member
Jul 1, 2011
342
VA
About 3 years ago I added more sand to my filter following the exact directions but after backwashing a few times it spit out what it didn't want. Now I just leave it where it naturally wants to be which is around 3/4 full.
 

jblizzle

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May 19, 2010
42,327
Tucson, AZ
When I changed my sand, 2 weeks ago, the sand level was down to about half the body level also. So I know your confusion. The only thing I can think of is when backwashing the sand partials grate against each other turning some of it to dust which gets flushed out during backwash. That would explain why no sand gets sent back to the pool and why the level will decrease.
No way you are turning sand to dust. More likely some is lost when backwashing.
 

C3Cl3N3O3

Bronze Supporter
May 25, 2015
179
Fort Mill, SC
Hello all, I just ran into this puzzle while replacing the laterals and filter sand. I've got a 10-year-old Hayward S220T, and the "required amount" of filter sand is stated at 250 lbs on the front plate. I loaded exactly 250 lbs of fresh filter sand, and it was well short of the 6" from the top stated in the manual (I'd say it was over 12" from the top). Given this dilemma, I loaded some of the old sand on top and got it closer to 7" or 8". Even that required a significant amount of additional sand, 100 - 150 lbs I'd say. Now I'm wondering if I made a good call on that. The old sand filled about half the tank and ran 12 PSI when clean. With the mix of old and new sand filled up higher, the PSI only increased to 13 PSI or so. I've had it running for 24 hours and the water clarity looks good. The jets seems to have the same water pressure as before. The backwash cycle also works perfectly. So it seems to be running well, but I'd like to have a better understanding of this. I opened a case with Hayward as well. I'm hoping the 250 lbs is just a minimum, and you can load the additional amount for better filtration if desired. I'm not super-excited about going and vacuuming 100 lbs of sand back out...
 

pondfishr

Well-known member
May 1, 2015
102
kingston springs, tn
I just changed my sand, laterals, and lateral hub yesterday evening in a Triton II TR60. I had been getting a little sand in my pool since we installed a new liner. Actually changed the sand a few weeks earlier this year and figured I had overlooked a bad lateral. This time I replaced all 8 laterals and hub. The ones I removed looked fine, "go figure". I followed the recomended 50 lbs pea gravel and 275 pounds of sand. The pea gravel took up a little more space than if I had used 100% sand. Sand level was right below the inlet pipe with the diffuser. Freeboard space is the beveled space at the top of the filter. Seems to work just fine but too early to tell about the sand residue in our pool. If it returns the only thing I can think of is there must be some smaller diameter sand residue from the liner change that gets recirculated though the filter and sent back into the pool over and over again. Has anyone had this problem before? If it comes back I guess the next step is to vacuum the sand out the waste port of the filter.
 

Tek

Active member
Mar 20, 2015
34
Louisville, KY
I just changed my sand, laterals, and lateral hub yesterday evening in a Triton II TR60. I had been getting a little sand in my pool since we installed a new liner. Actually changed the sand a few weeks earlier this year and figured I had overlooked a bad lateral. This time I replaced all 8 laterals and hub. The ones I removed looked fine, "go figure". I followed the recomended 50 lbs pea gravel and 275 pounds of sand. The pea gravel took up a little more space than if I had used 100% sand. Sand level was right below the inlet pipe with the diffuser. Freeboard space is the beveled space at the top of the filter. Seems to work just fine but too early to tell about the sand residue in our pool. If it returns the only thing I can think of is there must be some smaller diameter sand residue from the liner change that gets recirculated though the filter and sent back into the pool over and over again. Has anyone had this problem before? If it comes back I guess the next step is to vacuum the sand out the waste port of the filter.
I replaced the laterals and the standpipe assembly about a month ago. It did not fix my issue of sand blowing into my pool. I've tried to learn to live with it, but it is pretty annoying. I tried putting socks on my returns to catch the sand but it seems to get through them as well. Although it did turn my socks a sandy color. I suppose my next steps would be to replace the diverter in the multiport valve. I checked the spider gasket and it looked fine. Tomorrow I plan to check the freeboard space to make sure it is correct. Beyond that I'm stuck on what else it could be besides taking out the sand to check the laterals again. Although they looked fine the first time I did this and I went ahead with the replacement anyways...
 
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