DE in sand filter 3cups and no move

[joshuaj1975]

So I’m thinking either more DE or I can have my vacuum suck from pool only and have return jets set to return to spa only. This “dust” settles quickly and then manually vac to waste from the spa…..??

Kinda stumped as to why this goes through the filter so easily…?

 

[Texas Splash]

Quick re-cap:
- OCLT passed
- Issue started happening after acid wash/plaster work
- Sand is new; no change in PSI
- DE doesn't seem to help
- Water clear but not TFP/crystal

The only last item I can think of that "might" allow you to pass an OCLT but still return "might" be Mustard Algae, but that wasn't first on my list. Let's get a fresh set of eyes on this in case we've missed something; @JamesW @JoyfulNoise @duraleigh

 

[wireform]

Did you add enough DE to raise the PSI by1 number cuz a 500 pound filter needs one then that.

 

[joshuaj1975]

Did you add enough DE to raise the PSI by1 number cuz a 500 pound filter needs one then that.

Did you add enough DE to raise the PSI by1 number cuz a 500 pound filter needs one then that.

Needle has not moved. 3cups seemed to make no difference at all.

 

[JoyfulNoise]

Sand half way up the filter doesn't sound right. Did you check the required free-board length and ensure that you have enough sand.

Also, DE getting through could either be from channeling (old sand), which is unlikely, OR one or more of your laterals is compromised some how. Given that the installers screwed up the original setup, you may need to recheck the internals. Sucks, but that's what I wold do.

 

[wireform]

The following is with clean psi reading. Add cups and wait a few minutes to see if there's movement and keep going till there's 1 psi movement that will be your magic amount that you can put in without checking as long as it's done with consistency ie. A freshly backwashed filter will usually settle back to square one every time.....

 

[joshuaj1975]

Sand half way up the filter doesn't sound right. Did you check the required free-board length and ensure that you have enough sand.

Also, DE getting through could either be from channeling (old sand), which is unlikely, OR one or more of your laterals is compromised some how. Given that the installers screwed up the original setup, you may need to recheck the internals. Sucks, but that's what I wold do.

Its a little more than half way...

There doesn't appear to be any DE coming out of the returns back to the pool

I pulled the laterals out and check them extensively and flushed out well. It seems to filter the pool just fine its this residual that I can't seem to get rid of, Its never worse or better.

 

[joshuaj1975]

The following is with clean psi reading. Add cups and with a few minutes to see if there's movement and keep going till there's 1 psi movement that will be your magic amount that you can put in without checking as long as it's done with consistency ie. A freshly backwashed filter will usually settle back to square one every time.....

I have just read that 1-2 cups (I've done 3 cups so far) should do it and didn't want to "over do it", which probably isn't possible until you start to get a higher psi. reading assuming its not being returned to the pool.

 

[wireform]

Until 1 psi it's not doing much but then too much will build pressure immediately. With the 1 psi rise you also will need to backwash sooner then without it as it'll catch more of the fine stuff and start restricting.

 

[Texas Splash]

Its a little more than half way...

Sand filters are generally filled about 2/3 the way up - kind of along that upper curve/bell shape. So if it's low, I would add more sand. May or may not be directly related to that sediment, but might explain why the pressure isn't rising with the DE as quick as expected..

 

[wireform]

If you called customer support they can give you the exact measurement from the top of the sand to the opening of the vessel so there's no guessing around.

 

[jtpipkin]

I've got a sneaking suspicion that the lack of movement on the gauge is because it's a 100 psi gauge. He's a got a big filter and a ridiculously high reading gauge. I'd also be surprised if that dust isn't sand. You sure they used the right kind of pool filter sand?

 

[JoyfulNoise]

From the Hayward Manual (for the S310T2) -

Carefully pour in correct amount and grade of filter sand, as specified on Table 2. (Be sure center pipe remains centered in opening). Because filter sand is not all the same. THE LEVEL OF SAND MUST REMAIN A MIMIMUM OF 10” FROM THE TOP. Remove sand shield from internal pipe.

https://hayward-pool-assets.com/assets/documents/pools/pdf/manuals/IS210T.pdf

I would also agree that the 100psi pressure gauge is a bad idea. Buy a liquid filled gauge that reads up to 30psi and gives you 0.5psi increments. No residential pool pump can generate a pressure greater than 50psi and so a 100psi gauge is a waste.

 

[IceShadow]

For what it's worth: I have to add 6-7 cups of DE to get my PSI to raise by 1.

 

[joshuaj1975]

Until 1 psi it's not doing much but then too much will build pressure immediately. With the 1 psi rise you also will need to backwash sooner then without it as it'll catch more of the fine stuff and start restricting.

I think I'm gonna go ahead and keep adding and see what happens....

 

[joshuaj1975]

I've got a sneaking suspicion that the lack of movement on the gauge is because it's a 100 psi gauge. He's a got a big filter and a ridiculously high reading gauge. I'd also be surprised if that dust isn't sand. You sure they used the right kind of pool filter sand?

Yes I checked when pulled out and its the silica type sand

 

[joshuaj1975]

From the Hayward Manual (for the S310T2) -

https://hayward-pool-assets.com/assets/documents/pools/pdf/manuals/IS210T.pdf

I would also agree that the 100psi pressure gauge is a bad idea. Buy a liquid filled gauge that reads up to 30psi and gives you 0.5psi increments. No residential pool pump can generate a pressure greater than 50psi and so a 100psi gauge is a waste.

30psi is on order

 

[jtpipkin]

30psi is on order

FWIW, I keep a 15 psi oil filled gauge as well since I run my two speed pump on low 99% of the time. My pump usually runs around 3-4 psi clean. If I'm ever unsure, I slap that one in to confirm.

 

[joshuaj1975]

Ok. So far.
Was gone for 2 days so raised fc to 10-11ppm
-backwashed any de that was in the filter
-had filter suck from pool only and return to spa only.
-vacuumed all debris in spa to waste
-installed 30psi. Gauge
-took fc level to 10ppm and won’t let fall below 6 (pool is clearing up and have a more blue tint)
-put filter bag in pump filter and psi. Dropped from 9psi. To 5psi. From junk it caught. Did it again same result. Have 3rd bag in there(think I’ve got out any left over debris it could catch).

Last night OCLT 10ppm
This morning 10ppm

Today
Gonna remove multi port valve and check sand level. Pretty sure I will be adding some.

Also gonna try and get a rebuild kit for the valve.

Any other suggestions are greatly appreciated.

Thanks

 

[IceShadow]

Are you doing a SLAM? You’re saying “clearing up and more of a blue tint” which makes me think you have algae and should be SLAMming.