Cloudy returns on pump start - Filter Balls

[OVAZswim]

Hi all!
First off, this home/pool are new to me as of February 2024. The pool was refinished with pebble tech in December of 2022 along with a new VS pump and sand filter.

I am not sure how long in total this has been happening, but it’s been at least a few weeks now since I first noticed it. When the pump first starts up, the returns are clear for about 5 seconds and then this cloudy mess comes out for about 5-10 seconds before they go clear again. There is no visible discharge again until the pump is started up from being off. This same cloud is also visible during a rinse after I backwash the filter.

Most recently, I captured some of this cloudy water in a small test bottle to see what I could see. It was only after about 10-15 min that there was some visible “dust” at the bottom of the bottle. It’s obviously extremely fine and not granular like the filter sand.

The only thing I could come up with is that this stuff is too fine for the sand filter to capture. What I can’t rationalize however, is why it only happens for this brief moment on pump start.

Any ideas?!

 

[Texas Splash]

Dead algae perhaps? Do you have your TF-100 yet? If so, or when you get it, I would do an Overnight Chlorine Loss Test. It would be good to rule-out that stuff as dead organic material before looking at the system itself.

 

[Mdragger88]

Does the sand filter have #20 pool filter sand in it or some other media? Like zeo perhaps?

 

[Lake Placid]

I’ve seen it on a couple of pools I service. I haven’t diagnosed it completely, but I usually see it when the filter is extremely saturated with dirt and is running at high pressure. Leads me to believe it’s dirt/organics being forced through the media. Also if your VS pump is running on a high rpm it could be flooding the filter not allowing the dirt to be trapped. When I’ve backwashed and slowed down the pump speed, the issue doesn’t return.

 

[Darin]

Any ideas?!

I would give this a try for diagnosing.
1. Start pump on slow speed. get everything up to low speed operating pressure and return. Hopefully it will prime OK. YOU might have to start fast and immediately switch to slow when primed.
2. Crank up the VS to your normal operation speed. Are you getting the "stuff" coming out of eyeballs?

What happens?

 

[OVAZswim]

Dead algae perhaps? Do you have your TF-100 yet? If so, or when you get it, I would do an Overnight Chlorine Loss Test. It would be good to rule-out that stuff as dead organic material before looking at the system itself.

Forgot to update my signature, but yes, I do have my TF-100. I did a SLAM 2 weeks ago and successfully completed it with 0.5 CC and 0 overnight chlorine loss. CC is now 0 as well.

 

[OVAZswim]

Does the sand filter have #20 pool filter sand in it or some other media? Like zeo perhaps?

Honestly not sure. It does call for #20 on the name tag of it, but I have never opened it to verify.

 

[Mdragger88]

Also did you mean that water & a cloud comes out of the return when you’re on rinse mode?

 

[OVAZswim]

I’ve seen it on a couple of pools I service. I haven’t diagnosed it completely, but I usually see it when the filter is extremely saturated with dirt and is running at high pressure. Leads me to believe it’s dirt/organics being forced through the media. Also if your VS pump is running on a high rpm it could be flooding the filter not allowing the dirt to be trapped. When I’ve backwashed and slowed down the pump speed, the issue doesn’t return.

I do live in Arizona, so the amount of sediment/dirt wouldn't be a surprise. I don't have a high pressure issue, though. I run my pump at 2700 rpm (out of 3400 max) and my sand filter only sits at about 10 psig. If it was something being forced through, I would've thought that on a backwash/rinse it would get rid of it and stop. No matter how many backwashes I do, it always happens on pump startup out the returns.

 

[OVAZswim]

Also did you mean that water & a cloud comes out of the return when you’re on rinse mode?

Not on a rinse, no. I have my backwash/rinse line plumbed to a river rock bed on my side yard so I can see it go from clear to cloudy, and back to clear during the rinse. Nothing visible on the backwash.

 

[Texas Splash]

After everything you have described, I find myself going back to the sand that was added when the equipment was replaced back in 2022. No telling what they put in there. Some "pool sands" have been known to be bad (small and too fine). This substance you are seeing seems to be puddling/settling down at the laterals, then when the system turns off. It takes a few seconds to purge when it comes back on and to finally reach the jets, then eventually that batch of sediment is gone/purged. At some point you may have to just open up that filter to check.

I hope the techs used unions when they did the install.

 

[Mdragger88]

Glad to clear that up about the rinse!
Zeo is known for the poofing on startup.
Its the reason I replaced mine with regular sand.

 

[OVAZswim]

Thank you all for the replies! I'll go ahead and open up my filter and see if I can tell what's in there. Might as well replace it at this point and know what I'm working with.

 

[OVAZswim]

Hey all. Thought I would post an update after finally getting a break from work travel to change the sand.

To my surprise, when I opened up the filter there was no sand inside. Instead, there were these filter balls that appear to be sold at some pool stores. They were awful to remove. On top of that, they were barely working anymore. All it would take was one storms worth of some debris and I would have to backwash 2-3x to keep my vac running because the pressure would climb 60% or more.

I did a thorough cleaning and installed the proper 300# of HTH #20 sand. After the initial 2 min backwash and rinse, there is no more puff at startup and my filter pressure is even lower than before.

 

[Texas Splash]

Great catch! Glad to hear things are going well again.

 

[Mdragger88]

Wowza!
Filter balls are just sooo gross
So glad you looked!!