In the process of SLAMming. I don't think my sand filter is working.

[nasparkles]

Took off pool cover and pool looked like a pond. Dark green with algae. Balanced water and started SLAM 24 hours ago. Within first 2 hours the water turned a blue-green color, no visibility (I can see the patterns on the side of the pool about 4 inches down). Continued SLAM, but it has been 24 hours now and the water looks exactly the same, also the filter pressure has not increased at all. Do I need to put fresh sand in the filter? Or am I just being impatient? I feel like the pressure should be increasing at least a little bit, and the water should be slightly clearer after filtering for 24 hours. Thanks in advance for your help.

 

[Bama Rambler]

When was the last time you deep cleaned your filter? The sand could be channeled, but if it is all you need to do is give it a good deep cleaning. There is a good thread here about how to do that.

Does the pressure gauge go to zero when you shut the pump off?

 

[Donldson]

Ponds take more than 48 hours to clear. I didn't cover my pool this year, the water was so murky I couldn't even see the skimmer basket for several days in to the SLAM even as the water turned from deep green to milky blue.

Have you backwashed to see that the filter is filtering things out?

 

[nasparkles]

When was the last time you deep cleaned your filter? The sand could be channeled, but if it is all you need to do is give it a good deep cleaning. There is a good thread here about how to do that.

Does the pressure gauge go to zero when you shut the pump off?

Yes, the pressure gauge drops to zero when it is not on. I have not deep cleaned yet, as this is only the beginning of year 3 for our pool. But I will check out that thread. Thank you!

 

[nasparkles]

Ponds take more than 48 hours to clear. I didn't cover my pool this year, the water was so murky I couldn't even see the skimmer basket for several days in to the SLAM even as the water turned from deep green to milky blue.

Have you backwashed to see that the filter is filtering things out?

I have not backwashed yet, since the pressure hasn't gone up yet at all. I definitely expected this process to take time, I just thought I would have to backwash pretty frequently due to algae clogging the filter.

 

[nasparkles]

Yes, the pressure gauge drops to zero when it is not on. I have not deep cleaned yet, as this is only the beginning of year 3 for our pool. But I will check out that thread. Thank you!

Thanks for the thread info, I am going to do a deep clean this weekend. I can actually see the bottom of the pool now, so the process is just taking much longer than I am used to. Just out of curiosity, what does it mean if the pressure gauge on the filter doesn't drop to zero when you turn the pump off?

 

[nasparkles]

I have not backwashed yet, since the pressure hasn't gone up yet at all. I definitely expected this process to take time, I just thought I would have to backwash pretty frequently due to algae clogging the filter.

I forgot to ask you if you had to backwash at all throughout your slam process? Pool is slowly getting clearer, so that's encouraging! I can actually see the bottom now.

 

[Richard320]

Thanks for the thread info, I am going to do a deep clean this weekend. I can actually see the bottom of the pool now, so the process is just taking much longer than I am used to. Just out of curiosity, what does it mean if the pressure gauge on the filter doesn't drop to zero when you turn the pump off?

It means it's useless. The innards got frozen and messed up. It's not just a matter of offsetting by so many psi.

And your pool's behavior seems completely normal. The cloudiness is not unlike the CYA test. Can you see the difference between 150 and 200? No, because the lines would be so close together they'd overlap. They don't even print those on the view tube. You're clearing, and probably a sizable reduction, but it isn't visible. And since your pool was covered, you just have dead algae, not a whole bunch of leaves and twigs and mud, which s why you aren't seeing the pressure skyrocketing.

Backwash when the pressure rises 25% from clean. A slightly dirty sand filter actually filters better, so don't get gung-ho with backwashing. But if the return flow slows down noticeably, then it is time, regardless of the gauge.

 

[nasparkles]

It means it's useless. The innards got frozen and messed up. It's not just a matter of offsetting by so many psi.

And your pool's behavior seems completely normal. The cloudiness is not unlike the CYA test. Can you see the difference between 150 and 200? No, because the lines would be so close together they'd overlap. They don't even print those on the view tube. You're clearing, and probably a sizable reduction, but it isn't visible. And since your pool was covered, you just have dead algae, not a whole bunch of leaves and twigs and mud, which s why you aren't seeing the pressure skyrocketing.

Backwash when the pressure rises 25% from clean. A slightly dirty sand filter actually filters better, so don't get gung-ho with backwashing. But if the return flow slows down noticeably, then it is time, regardless of the gauge.

Today I could see the bottom well enough that I was able to start vacuuming some big blobs of algae that were in various spots. As soon as I started vacuuming to the filter, the algae simply shot right back into the pool thru the return. This has to mean my filter isn't working well at all, right?

 

[Richard320]

Today I could see the bottom well enough that I was able to start vacuuming some big blobs of algae that were in various spots. As soon as I started vacuuming to the filter, the algae simply shot right back into the pool thru the return. This has to mean my filter isn't working well at all, right?

Yes. It's either got an internal problem or the multiport is set on bypass.

 

[nasparkles]

Okay. I ordered some replacement parts and will have to wait for a new multiport clamp to come in before I can get the filter open to see inside. (1 screw on the clamp is stripped and I'm going to have to break the clamp to get it off.) In the meantime I vacd the blobs to waste and put it back on filter. Not sure what else I can do for now. Thanks for taking your time to help me out with my questions. It is much appreciated!

 

[nasparkles]

Update: I did notice a drop in the return pressure, even though there was no change in the filter pressure. Backwashed and water was FILTHY! Put some DE in to help filtering and overnight the pool was crystal clear. Still algae spots on bottom of pool tho. I have continued shocking every day, once in late morning and again in evening once the sun goes down. I am officially on day 10 now. It has been 3 days since the pool water cleared, and I think the algae on the bottom is slowly clearing...I think. I'll give another update when I get the spots cleared up.

 

[Richard320]

Update: I did notice a drop in the return pressure, even though there was no change in the filter pressure. Backwashed and water was FILTHY! Put some DE in to help filtering and overnight the pool was crystal clear. Still algae spots on bottom of pool tho. I have continued shocking every day, once in late morning and again in evening once the sun goes down. I am officially on day 10 now. It has been 3 days since the pool water cleared, and I think the algae on the bottom is slowly clearing...I think. I'll give another update when I get the spots cleared up.

By Day 10 any visible algae should have been scrubbed away. Is it embedded in Calcium Scale or what? It won't scrub off and vacuum up?

 

[nasparkles]

By Day 10 any visible algae should have been scrubbed away. Is it embedded in Calcium Scale or what? It won't scrub off and vacuum up?

It vacuums up easily, but by the next morning it reappears, although a little less each day.

 

[Richard320]

It vacuums up easily, but by the next morning it reappears, although a little less each day.

Only dead algae clumps up like that so you're still killing something.

 

[nasparkles]

My plan is to keep shocking until I don't see any traces of the algae, brush, and then do a mustard algae shock just to be certain. Then I'll let the chlorine level drift down to normal and see what happens. Pray for me!

 

[nasparkles]

Day 16 and I don't think that it's ever going to go away. I don't understand how SLAM took me from a pond with floating scum on top, to crystal clear water in 7 days, but over the course of an additional 9 days there has been very little progress. I feel like the past 7 days have had slight to zero progress depending on the day. Starting to feel like the definition of insanity...repeating the same actions, expecting a different outcome. I will keep going on until the weekend, then I am thinking maybe I should replace the sand in the filter and see if that helps at all. Only waiting for the weekend because I don't have time during the week. Super sad right now. I want to swim!!

 

[aeh0603]

It sounds like you still have a little bit of algae hiding somewhere. Have you checked inside or under your stairs/ladder, inside the skimmer/weir door, do you have a light niche it could be hiding behind? I would also recommend a deep clean of your sand filter. Sand doesn't really go bad unless it gets gummed up by the use of FLOC or clarifier, but it can develop channeling over time which makes it less effective. I've seen other thread similar to yours where the tail end of SLAM dragged on and was passed quickly after deep cleaning the sand.

Also, it's safe to swim as long as FC is between minimum and SLAM level for your CYA and you can see the entire bottom of the pool.

 

[nasparkles]

It sounds like you still have a little bit of algae hiding somewhere. Have you checked inside or under your stairs/ladder, inside the skimmer/weir door, do you have a light niche it could be hiding behind? I would also recommend a deep clean of your sand filter. Sand doesn't really go bad unless it gets gummed up by the use of FLOC or clarifier, but it can develop channeling over time which makes it less effective. I've seen other thread similar to yours where the tail end of SLAM dragged on and was passed quickly after deep cleaning the sand.

Also, it's safe to swim as long as FC is between minimum and SLAM level for your CYA and you can see the entire bottom of the pool.

I haven't put my ladder in yet, and I have cleaned every surface that I can. Someone else mentioned deep cleaning the sand and I think that is also a good idea. I was about to attempt that about a week and a half ago, but one screw on the filter clamp got stripped and we couldn't get the clamp off. So frustrating! I have gotten a new clamp, so I can break the old one off and get to the sand this weekend. I didn't realize we could swim at slam level, so that's really good to know! It will make the hard work more bearable if I can actually get in and cool off. We've already had some pretty hot days here in Alabama! Thanks for giving me some motivation to keep going!

 

[nasparkles]

Today is the day I am going to address the sand issue. I let the chlorine drift down to 6 ppm last night and this morning it measured at 3 ppm, so burned a lot of chlorine overnight, which tells me something is growing rapidly ar normal levels of chlorine. Went out this morning and there were many more spots of algae than usual. Probably 10 times the amount. But only on one side of the pool. I tried to attach pics but it said it was too large for the server. I don't know what's up with that. I'll try to attach to a separate post. Another thing is, I check the pool in the early evening and the bottom is still clear, but overnight everything grows apparently. Anyways, I really hope changing out the sand will do the trick, because if not I will be at a total loss! Heading to the store now....