Sediment in pool…how to handle when going out of town?

[pfitz4]

I have sediment collecting in little piles on the floor of the shallow end, the bottom of the stairs, along seams and in corners, etc (photos 1 and 2). It also gets dusty on one side of the slanted walls of the deep end (photo 3). The sediment is brown, dusty, slightly gritty and puffs away instantly. This happens to my pool most years in the spring/early summer but seems to be worse this year. We have had a lot of rain in the past few weeks. The water is sparkling clear otherwise. My pool is in full sun, no nooks and crannies for algae to hide. We have a lot of trees. I opened the pool April 1 and it was very green after a relatively warm winter.

I boosted FC to SLAM level a couple of days ago. Sediment is better but still there. I run Polaris frequently, brush, and I have backwashed twice this week.

Last night I lost 2ppm FC.



Question 1 - what do you think the problem is?

Question 2 - leaving town in 3 days and will be gone for a week. What is your advice on how to handle this?

FC 16
CYA 40 (see note below)
TA 70
PH 7.5
Salt 3200
Temp 82
Note: I know CYA is low for a salt pool. I had it at 60 but it dropped after all the rain. I plan to raise it to 70 but wanted to keep at 40 while FC is at SLAM level.

 

[bobloblaw42]

Appropriate (high end of range) FC production and circulation while out of town can handle sediment remaining in the pool. This looks like pollen.

Typically if the sediment is re-appearing it means you're either in a high pollen production season (grass season maybe?) and its just new debris entering the pool or you may be backwashing too often and its pushing through filter back to pool. Try letting the filter get dirty and only backwash when you're 25% above your clean (post-backwash) pressure on high speed. If you have or have access to some pool grade DE you can accelerate the 'get filter somewhat dirty' process. You could try adding a quarter cup at a time through the skimmer (remove any skimmer socks first) until you have raised your PSI on high speed by 1.0. Now try vacuuming. The pool grade DE should help the filter catch all the very small particles that sometimes pass through a relatively clean sand filter.

 

[pfitz4]

Thanks for the feedback. I’ve been hoping this is just pollen/dirt but when the OCLT showed a loss of 2ppm, I began to think there could be algae. I have fresh reagents on order so I plan to redo the test asap.

Great advice about the DE and backwashing, I’ll give that a try after the trip. I’ve had this sand filter since buying the house 9 years ago, and the sand has never been replaced or cleaned other than backwashing. I imagine that could be an issue. Opening the filter will involve cutting pipes so I’ve been postponing that as long as possible.

 

[pfitz4]

Would you recommend raising CYA before I leave town, if I still haven’t passed OCLT?

 

[bobloblaw42]

Don't raise the CYA if you haven't exited SLAM by time you leave. You'll have to hope he SWG can keep it from getting too out of control and you'll likely need to restart SLAM upon return. Having to restart SLAM is why you'd not want to raise CYA yet.

 

[Newdude]

I’ve been hoping this is just pollen/dirt but when the OCLT showed a loss of 2ppm, I began to think there could be algae

The 2ppm loss proved it. No thinking required.

You thought something was up and ran an OCLT. (Bravo). The results speak for themselves either way. In this case, SLAM on right until you leave. More effort makes it go quicker, no matter how bad it might be. Dose often and go right until bedtime. If you're around for the weekend, hit it every 2 hours and run errands in between. If you need to run out before the times up, dose early and it'll buy you the next block of time away.

Vac and brush at least once daily. Scrutinize every hidden inch and then thoroughly clean them. Ladder rails hold a gallon or two of old water on either side. All up in the skimmer, etc etc.