Sand from filter/return jets?

[mike.stocker]

Howdy, I am having a difficult time fully verifying that this is sand coming from my return jets. It is definitely sand that I pick up in my vacuum however when I put a skimmer sock over my return jets, somehow it never gets caught in it. They’re always clean when I take them off. And yet, as soon as I take the sock off, this stuff shows up again not too long afterwards. So has to be coming from my filter right? It’s a very small amount each day but seems to collect in the same spots/depressions of my liner bottom. The filter was just installed last year although I bought it secondhand so it wasn’t brand new. The folks who installed it said it looked good so I assume they inspected the laterals before they added the sand but perhaps not. I didn’t know enough at the time to think to do that myself as I hadn’t been a studied member of TFP for very long at that point. I do know they installed a new gasket in the MPV because I helped scrape the old one out as it had been glued in.

Any ideas as far as how I might catch some of this stuff from the return jet to 100% confirm it is sand from my filter? I even tried two skimmer socks with some polyfil sandwiched between them and it still didn’t catch anything. I was happy about this obviously until I checked an hour after removing them and this stuff was on the bottom again after having not been there all day. The only other possible source of the sand I can think of is bugs as I do get a lot of ants and beetles in the pool most days.

 

[Texas Splash]

It is odd that you can't catch any of it with a sock or nylon at the jets. Are you trying all the jets? Your return (pressure) line leaving the pad back to the pool is probably a single branch before it either splits or simply has "T's" along the way for each jet. Sometimes sand might take a preferred route. I see that with my SWG bubbles. They take the first exits (jet fittings) to escape. Three of my jets I see bubbles and the other three none.

But sadly yes, unless you find another source for the sand, you may end-up making a day of it to empty and inspect the laterals to be safe if it continues or gets worse.

 

[mike.stocker]

Thanks @Texas Splash. I only have two return jets and had socks over both of them for my most recent test. That’s what I was afraid of though, not looking forward to that.

 

[Lake Placid]

Have you considered outside sources? What you are showing isn’t a lot of sand and could possibly be environmentally related. I’ve got a commercial pool that is an open vacuum DE system, but every cleaning (2x a week) I vacuum 3/4 to 1 cup by volume of sand off the bottom of the pool in the exact same places. The depositing on the floor is likely a culprit of how I have the return jets positioned and flow characteristics.

After a moments thought, on my personal pool with it covered with a looploc mesh cover I have pulled off a cup or two of sand that is sitting on top of the cover prior to opening. This accumulation has happened in a few days as it’s been clear and clean over the winter and I’ve blown it clean during yard maintenance, but a pile appears out of nowhere when getting ready to pull the cover particularly after a rain.

 

[mike.stocker]

That’s what I thought initially but it seems like every time I put a sock over the return jets, it stops. And yet there’s nothing in the sock, which doesn’t make sense so maybe it’s just coincidence that when I take it off, the stuff seems to reappear on the bottom. I’ll have to do some more testing. I also have a looploc mesh safety cover and I don’t recall any sand accumulating on it during the offseason. You’re right though, it isn’t a lot although does get worse if I don’t vacuum it up for a few days.

 

[mike.stocker]

I’m definitely going to have to do some more testing. I dove down yesterday before I put the vacuum in and the stuff was dark green and would cloud up and disperse before I could get it between my fingers suggesting it is dead algae? So now I’m thinking the tiny bit of sand that my vacuum picks up is being blown or brought in and the dead algae is coming from my filter. Regarding that possibility, last year when I acquired this pool and decided to take on the task of managing it myself (and subsequently found this awesome resource that is TFP), I vacuumed up a bunch of dead algae to my filter like a moron. The pressure shot up super quick and I realized I made a big mistake not vacuuming to waste. It didn’t seem like a lot looking down into the water at the time but it clearly was too much. I am now wondering if that’s what is being blown back into the pool since it seems to subside anytime I put a skimmer sock over the return jets. I am going to test the pump on low as I feel like I wasn’t dealing with this when I was only running it on low. I’ll also test on recirculate. I have a suspicion that it only shows up when the pump is running on high. I actually dealt with this issue last season after my SLAM (and that aforementioned vacuum to filter session) and would just vacuum the stuff up every day with a Pool Blaster vacuum. My water is otherwise crystal clear, my CC never gets above .5, and the last few OCLTs I’ve done, I have passed. Thinking my filter might need a deep clean.

 

[Texas Splash]

the stuff was dark green and would cloud up and disperse before I could get it between my fingers

That actually sounds like live algae, but you've pass a couple OCLTs recently? . The filter shouldn't be the cause. No sun inside and always has chlorinated water pushing through it. I would suggest posting some pics of your pool and equipment pad form a couple angles. Let's see what you have to work with there.

 

[mike.stocker]

That actually sounds like live algae, but you've pass a couple OCLTs recently? . The filter shouldn't be the cause. No sun inside and always has chlorinated water pushing through it. I would suggest posting some pics of your pool and equipment pad form a couple angles. Let's see what you have to work with there.

I was thinking maybe dead algae from that old vacuum session I mentioned where I forced a bunch of dead algae through the filter. This has been an ongoing issue since then and that was last season before I closed, not long after I bought this property. I chalked it up to dirt/pollen for a while. Then I thought sand because of what I was seeing in the vacuum. But after seeing it puff up like that when I tried to approach it slowly with my hands, now I’m thinking algae. I passed an OCLT a couple of weeks ago though. Those results are attached. For some reason I didn’t test CC for that one but I only lost .5ppm of FC overnight. Also attached are full test results from two days ago.

Also attached are the requested photos I just took. Very simple setup. I vacuumed a little while ago before I got in so nothing to see on the bottom really apart from an old, fading liner I inherited with some staining that’s been there since I acquired the pool. Pump is running on high right now so if my theory about it showing up only while the pump is on high is correct, I should start to see it on the bottom again soon. I’ll snap some more photos if that happens. I will also do another OCLT tonight. I am actually leaving town tomorrow for 5 days so plan to bring chlorine up to SLAM level in the morning.

 

[Texas Splash]

While the salt and CYA are low for a salt pool, I don't think that's a concern at the moment. FC in a good place, so nothing terribly alarming in your test numbers that would explain what's happening. Very simple set up at the pad. In the pool, I can't see everything, but no hollow steps or ladder? Just to be safe, skimmer and weir door areas clean and good? Do you have a main drain? If so, have you ever removed the cover to see what may be down there?

 

[mike.stocker]

While the salt and CYA are low for a salt pool, I don't think that's a concern at the moment. FC in a good place, so nothing terribly alarming in your test numbers that would explain what's happening. Very simple set up at the pad. In the pool, I can't see everything, but no hollow steps or ladder? Just to be safe, skimmer and weir door areas clean and good? Do you have a main drain? If so, have you ever removed the cover to see what may be down there?

Ah I should clarify I don’t have a SWCG. I had been reading up on the potential benefits of adding salt and borates so started tracking both. Added boric acid this past week. Was considering bringing salt levels up to 2000ppm next to see if I would notice a difference in water feel.

No steps but there is a ladder for the shallow end however I haven’t put it in yet this season. No main drain and skimmer looks fine. I scrubbed it pretty good when I opened.

 

[Texas Splash]

Going back to post one, you tried a skimmer sock and poly fill over the jets, but that may not have been fine enough. I would try a nylon if you can your hands on one. Something very fine.

 

[mike.stocker]

Going back to post one, you tried a skimmer sock and poly fill over the jets, but that may not have been fine enough. I would try a nylon if you can your hands on one. Something very fine.

Lol funny enough I ordered these mesh strainers earlier today. May still not be fine enough though, I didn’t think of using nylon. Good idea, thanks. I’ll try and find some.

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