SLAM done (I'm pretty sure) but sediment at the bottom of the pool

[tko]

I've been SLAMing for almost two weeks - brushing, filter has been running 24x7 for 2 weeks, and for the past couple nights, there has been no FC loss overnight, and CC is between 0 and .5 consistently. There's loss during the day as it's been sunny, and I've brought it up to SLAM levels again. The water is actually pretty clear (I can see a quarter at the bottom of the deep end), but I can see sediment settled to the bottom. When I brush or use the creepy crawly vacuum, it stirs everything up and gets cloudy, but it doesn't seem to be filtering the rest of this stuff well.

I'm thinking I should let FC fall, and use about 5 oz of clarifier (28k gallons pool), to help my sand filter out. I've used DE, and it's helped some, but not as much as I'd like.

My daughter's graduation party is on Saturday - it's slated to be 99 degrees here in Portland, OR. I hope they are wrong, but just in case, it would be nice to have the pool looking spiffy. Thoughts and suggestions? Warnings?

 

[needsajet]

I had this issue (slow to clear) until I learned to let my filter get a bit dirty, i.e. not backwash too much.

I also believe it filtered better when I slowed down my variable speed pump just for the first day or so to help it catch the fines, then I could speed it right up (this was plaster dust when it was new).

Based on the criteria, a SLAM is not done until the dust is gone.

Using your manual vacuum, hose and pole, and moving it very slowly across the floor when the pump first starts up in the morning might help. I also left my vacuum, upside down, in the bottom of the pool overnight sucking water to the filter. When I was done trying to help it along, I brushed to keep it stirred up so more of the dust would go to the skimmer, and on into the filter.

I think you're going to make it by Saturday. It takes a few days sometimes.

 

[tko]

It's been almost two weeks. Or do you mean a few days after the SLAM is done. I have to backwash because the filter hits ~30 psi. My filter has one speed, and vacuuming slowly on the bottom didn't help me, but I'll try the upside down thing.

You don't think a bit of clarifier would help to bind to bigger particles to help it along? My pump runs 24x7.

Thanks for taking the time to reply!

 

[tim5055]

What is your clean pressure after a backwash? You should only backwash when pressure rises 20-25% over clean.

 

[tko]

18-20 is the normal reading - we've been in the house since Feb, pool opened in early April and I've never seen the psi go below 18, but mostly it hovers around 20.

 

[needsajet]

It sounds like you're doing the right things for it to gradually clear up, and the pressure rise suggests the filter is clearing lots out.

The only thing I can think of to consider that hasn't been mentioned is to deep-clean your filter in case it's got some channels. Deep Cleaning a Sand Filter.

I suspect you rinse thoroughly after a backwash. I had to learn that lesson, which for me is 2 minutes then a couple minute's wait before re-starting it.

If I were you, I'd search (upper right of this page) on the word "clarifier" and read a few threads. You'll hear both sides of the story, good brands, etc. For me, DE done right (not more than a 1 PSI rise because too much DE will reduce your filtering efficiency) and time are the answer, plus slow bottom vacuuming, and afterwards keeping the water stirred up so the algae carcasses get to the filter. All assuming the SLAM level was high and mighty, and multiple OCLTs as you mentioned. The only clarifier I ever used that actually did anything on the plaster dust was labelled poly-diallyldimethylammonium chloride, FWIW.

Probably not recommended here and just my own opinion, but you can slow a single-speed down by throttling on the return side. At 30 PSI though, you're already slowed down. The upside-down vacuum would also slow it down depending how you hook it up, but personally, I avoid throttling the suction side of a pump any more than the plumbing and fixtures already do.

 

[tko]

Thank you. I have not deep cleaned the filter as I had someone out there who opened it up, and said it looked good. Also, I'm not in a position right now to be able to have water flowing all over the floor. I replenish DE after a backwash, so I'm wondering if that is an issue. I have researched and read about the clarifier viewpoints, and decided to try 6oz for by 28-20k gal pool. Waiting on it to clear now.

I was told to backwash 1.5-2 minutes (when pressure falls around 20), then I rinse for 30 seconds. Not long enough? And I don't wait before restarting pump - maybe that's another problem? There appears to be sand at the bottom of the pool (based on what I see in the hose when I disconnect. Not sure if sand got trudged in or if it might have come from the filter. Who knows - it was sitting closed for 2-3 years unused.

 

[tko]

How do you slow down the returns?

 

[needsajet]

Yeh, with only a couple days to spare, the deep clean might not be good timing anyway.

If there are any valves on your return lines, you can slow the flow by partially closing those, but keep an eye on your pressure, and when determining the +20%/25% backwash trigger, put them back where they were. Some of the experts here disagree that slower flow makes a difference in a clean sand filter; that's just been what happens to me.

The DE charge does the same thing and more predictably, so probably better to stick to that. Just make sure you're only causing a 1 PSI rise from the DE addition, and you babysit the filter afterwards. Be sure to use pool DE and not garden (or other purpose) DE. Backwashing cleans out the DE, so it is re-done each time. Once you learn your amount from following the procedure, you can use the same amount of DE next time.

Yes, I would rinse longer. Mine needs more rinse time than backwash time to avoid clouds coming out the returns back into the pool. Yours may be different, but just trying to give you the best chance of clean water for your party. You can tighten up the rinse time as you get used to it all.

You may not need the two minute rest after the rinse. I can't explain why, but it seems to work better for me. At least in my feeble mind, I believe stuff in the filter is settling back down. Experts here will say so if that's a useless step.

I still think you have a very good chance of getting there. A bit of white cloudiness is not dangerous or anything, and up to SLAM level is OK for swimming, but it would be nice to get you there for Saturday if we can.

 

[tko]

I really appreciate the info - I'm stepping out to check the FC now. Crystal clear would be so very nice....

 

[needsajet]

How's it going? Any less cloudy this morning?

 

[tko]

It was clearer as things had settled. No FC loss. I slow vacuumed, and PSI went to 30, so I back-washed, rinsed, added some water. Brushed so it got a little bit cloudy again, so we'll wait it out. CC was slightly high (> 0.5), so I think I'll need to keep SLAMing. Can the kids swim though, if I keep FC high?

 

[tim5055]

It was clearer as things had settled. No FC loss. I slow vacuumed, and PSI went to 30, so I back-washed, rinsed, added some water. Brushed so it got a little bit cloudy again, so we'll wait it out. CC was slightly high (> 0.5), so I think I'll need to keep SLAMing. Can the kids swim though, if I keep FC high?

It is safe to swim up,to shock level on FC, but the big thing is clarity. You have to be able to clearly see the bottom of the deep end to be safe to swim. If someone gets in trouble underwater you have to be able to see them.

 

[tko]

We can definitely see the bottom. I can see the drain clearly (and it's scrubbed clean), and the water is fairly clear, but not "sparkling clear". I was hoping for sparkling.

Thank you! I might send the kids in with brushes!

 

[needsajet]

Glad to hear it's progressing and getting cleaner Think about anywhere the green might be hiding, like maybe under the coping, surfaces that are hard to brush, etc. You're going very well on it.

 

[tko]

- - - Updated - - -

Thank you, everyone! The grad party was a success - my daugther (in yellow) was so grateful - her friends voted her party best food, best vibes, best pool.

I am forever grateful to this forum!! I will be making a donation to support the great work here!

 

[needsajet]

Great to hear, and see! Well done, dad

 

[tko]

...or Mom. Dad did vacuum to waste and removed dead mouse from skimmer (while mom screamed: "for the love of God!!!")....but mom did all the chem stuff.

This group hug should've been in front of the pool. It was 99 degrees in Portland OR on the day of the party.



tina

 

[needsajet]

Whoops!!! Dedicated mom - very well done And thanks so for your support of TFP as well