Tips on Diagnosing Potential Sand Filter Problem

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AquaBoy

AquaBoy

0
May 13, 2016
41
Savannah, GA
Hello to everyone,

I have been finding info from this site consistently that has aided in my (mostly) successful pool opening, so I want to say thank you to all who have contributed to this site already!

I now have a sparkling clear pool that is extremely inviting, except for one small problem. The last few times I have vacuumed, I have done so in the evening and when I went back in the house all was perfect. However, each time I would come out in the morning I have found that much of the sand I have vacuumed is back in the pool. At first I thought this was due to user error, but the only sand deposits seem to be located right where the water jets would have shot them back in. I also vacuum extremely slowly to make sure that I'm not simply dispersing sand by going too quickly. After perusing advice on these forums, I found a generally accepted idea that I should try vacuuming to waste, then switching to backwash for a couple minutes, then moving to rinse for approx. one minute. The last time I vacuumed I followed this series of steps only to find the same result the following morning. I am thinking it is likely something wrong with the sand filter, but before I skip straight to calling for a pool guy (they're either overpriced here or overpriced in general) I'd like to hear if anyone has any tips on other potential causes/solutions.

On a side note, I have never owned a pool and this is my first season opening it up. I did look back at the pictures on Zillow of the pool (during the
For Sale window they had a pool guy performing weekly maintenance) and actually noticed some sand in the same areas. So maybe this has been an issue for some time. I have not peeked into the sand filter, nor do I want to take that step and risk screwing something up before finding out from the folks here if you feel it may be something else entirely. Thank you all in advance for any advice/recommendations you may have!
 
You might want to make absolutely sure it's the filter before you start digging (literally).

Turn off the pump. Have someone hold a sock over a return, then turn the pump back on. That should cause sand to go into the sock if you have a problem with the filter.

Now you have to diagnose the problem. Could you please post the model of your filter?

The most common problem I have seen is when someone adds the sand improperly and either knocks a lateral loose or breaks the manifold or a lateral.
 
I was trying to upload a pic with my response but I don't believe it worked. If it shows up after this I will delete to make things less confusing..

Do you think I would be able to detect enough sand in the sock by turning the pump on without having vacuumed first? I ask because, for example, I vacuumed last Saturday evening. Sunday I came out and a small amount of sand was back in the middle of the pool straight out from where the jets are located. However, since then I have run the pump daily and no further sand has accumulated. So I am wondering if this sand is basically being recycled as I vacuum and coming right back out but not consistently being added as I turn the pump on from day to day. Not sure if that makes sense or has any logic to it, but I'm wondering if it would be easier to tell if I vacuum and then turn the pump on afterward with a sock?

The model of the filter is now in my signature. I will work on adding images since that requires a bit more work to get it uploaded properly onto the forum. Thank you!
 
Welcome to TFP :)

It could be sand, have you done a deep clean on you sand filter?

From the looks of it what most people think is sand is actually algae, could you get some and smear it on a paper towel, if it is sand you will know if it smears or is black/green then its algae

How are you water levels, could you post them up.. maybe someone will see something and be able to help :)
 
Right, what he said above. That's why I'd like you to do the sock test. It may not be sand. Whatever it is, that's a lot of it though. When I had a broken lateral, it wasn't putting out that much!

Sand is usually light brown too, that looks dark.
 
No, I have no idea what that means (deep cleaning the sand filter) but I will look it up. We moved in to the house in December and this is the first month I have been playing around with it while trying to get it opened. Basically I threw in shock whenever we had a bad rain and other than that I had a pool guy come out a month ago but it turned out to not get as warm as I was hoping. And for what he did, it seemed like a ridiculous price. I did have a small algae issue a couple of weeks ago on the sides and that has cleared up; I used algae control from Leslie's and have religiously brushed the pool every day since. However, it would not surprise me if that is the remnants of that algae that was killed off (or at least removed from the side walls). I will take a test in a few minutes and put those numbers up.

The follow-up question I would have is that if that is indeed algae, would it be normal for that to be vacuumed up only to return back through the jets after vacuuming to waste/running backwash/rinsing? Or would that mean the problem is algae AND possibly the sand filter? I'll post the numbers in a few minutes since that may tell more about the situation than my guesses. Also with the sock, is that literally just a standard white sock? I have seen this suggestion with applying shock as chemicals as well, but figured it might mean a "sock" made out of pantyhose. Thank you both for your responses!
 
I just went into the pool to get a closer shot of the sand/dirt.
The first pic appears to be sand. Tree coverage combined with my shadow makes it appear dark, but it is a light brown color and disappears when I gently sift it.




The second pic appears to just be soil, which is understandable as that may have happened from mowing/weed eating the lawn and it possibly getting into the pool.


So in the larger pic that I posted earlier, the small tight formations are light brown when up close and the overall darker area are dark brown and simply spin around and settle when sifting. Hope this helps
 

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Its dead algae. Your test results - what are you testing with?

I know your water is clear but those numbers are speaking to me. LOL

- - - Updated - - -

Do you know your CYA level?

Have you read the articles in Pool School - and understand "recommended levels?" :)

- - - Updated - - -

Can you take a pic of your skimmer(s) and your eyeballs? (circulation thoughts...)
 
I tested with two kits, one was the AquaCheck Test Strips. But since that seems like more of a quick and dirty rather than accurate method, I also used a Poolmaster 22260 5-Way Test Kit with Case - Basic Collection. I don't know the CYA level, and I was wondering why that was not mentioned in my test kit. Or maybe I missed it on the quick strips. I tested twice with the 5-way test kit since I didn't want to put up incorrect numbers when responding back on this thread.

I'll snap a pic of the skimmer, I assume you mean from the top? Are the eyeballs what I was calling jets? I looked it up online and it appears to be the jets but I can't tell 100%. Thank you both for your responses!
 
Take a look at my sig - they CYA chart.

Your FC is too low.
Your CC is too high - anything higher than .5 and you should SLAM the pool.

It appears to me that you have a "nascent" algae situation - thats what the brown dust is, dead algae collecting in the divots.

I recommend you order one of the recommended test kits so you can start SLAMming the pool to cure the issue but you can't properly SLAM without knowing your CYA level.

Yes jets are eyeballs... typically depending on the set up they should point down and to the right or left to create a circular flow pattern to direct surface debris towards skimmers and not straight into the middle of the pool :)

But every pool set up is different so that's why I asked....
 
I will do some reading in the recommended testing levels and switch to a kit recommended there. I was reading about the SLAM solution earlier and will go through that again so that I can go through that process once I know the CYA level. That is a good point and one that I was not aware of with the eyeballs. They do point straight out into the middle of the pool. I will adjust those as well. Thank you for all of your info and recommendations! Looks like I still have quite a bit of work to do!
 
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