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Thread: Foam in back of filter

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    Foam in back of filter

    So my water is near perfect, no odor crystal clear. But every day I see a cloudy green collection of foam in the back of the filter bucket, where the water circles down from the surface towards the filter. I've just been scooping it out with a scimmer and wiping the back of the wall.

    It's a 500 gallon tub, CH 180, TA 60, PH stable between 7.5-7.8. Using bleach sanitizer with CYA at 50 ppm. Tub is used 3-5 times a week.

    Only other relevant details are, I just got new filters which seem to have much less flow resistance than the older filters.

    I'd like to know what's causing the foam and is it a problem?
    Intex 15'x48" AG metal frame pool (4,440 gal), Krystal Clear (1600) 14" sand filter, Taylor K2006 test kit, Intex Deluxe Maintenance Kit/vacuum (love it!), Intex Deluxe Skimmer, BBB.

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    Mod Squad JVTrain's Avatar
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    Re: Foam in back of filter

    Do you have a FAS-DPD test for chlorine so that you can get your FC and CC values?
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: Foam in back of filter

    Quote Originally Posted by JVTrain View Post
    Do you have a FAS-DPD test for chlorine so that you can get your FC and CC values?
    I have a DPD drop test where u match the colors.

    Last night after short 2 person soak I added 6 oz of 8.25% bleach and my numbers for this morning (I got the green thick foam near filter as usual)

    FC 0.5 ppm
    CC 1 ppm

    Also cleaned my filters yesterday which didn't seem to solve it.

    Here's a pic after scooping and cleaning it out, then adding 1 oz of bleach and running jets for 10 min

    Intex 15'x48" AG metal frame pool (4,440 gal), Krystal Clear (1600) 14" sand filter, Taylor K2006 test kit, Intex Deluxe Maintenance Kit/vacuum (love it!), Intex Deluxe Skimmer, BBB.

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    Re: Foam in back of filter

    How long has it been since your last refill of the spa?

    Add the details of your spa to your signature and your location in your profile would help too.

    I'd recommend getting a FAS-DPD test kit so that you can more accurately determine FC and CC levels. This test has a definitive color change endpoint for each, rather than a color match block. You can get just the individual test reagents if you already have a DPD and pH test. TFTestkits.net

    But, if we go on your DPD test results alone, you need to do one of two things:
    1. If it hasn't been that long since your last refill, you need to SLAM the tub. Same procedure as you would use for a pool where you elevate the FC level to the recommended shock level based on your CYA and MAINTAIN that FC until you pass the procedure criteria. See the link in my signature for SLAM Procedure. However, your DPD test kit will not be able to measure the FC levels needed to complete the SLAM procedure as I'm sure your DPD test goes up to 10 ppm FC at the most, where the FAS-DPD will go up to 50 ppm FC. There's the difficulty as you can't truly complete a SLAM without a FAS-DPD test kit.
    2. Purchase a spa deep clean product. I HIGHLY recommend Ahh-some spa and jetted tub cleaner. This will remove residual biofilms that have likely accumulated in your spa plumbing based on the foam your are seeing. Perform the spa deep clean procedure using your existing spa water. Drain and repeat if you get a lot of scum and extreme grossness that Ahh-some will remove from deep in your plumbing. It's astonishing what comes out and how well it works. I'd also remove your filter from the housing and throw it in the middle of the tub when doing the treatment. Then refill and start with fresh water and certainly fresher plumbing. This option 2 is your best option, in my opinion.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: Foam in back of filter

    Quote Originally Posted by JVTrain View Post
    How long has it been since your last refill of the spa?

    Add the details of your spa to your signature and your location in your profile would help too.

    I'd recommend getting a FAS-DPD test kit so that you can more accurately determine FC and CC levels. This test has a definitive color change endpoint for each, rather than a color match block. You can get just the individual test reagents if you already have a DPD and pH test. TFTestkits.net

    But, if we go on your DPD test results alone, you need to do one of two things:
    1. If it hasn't been that long since your last refill, you need to SLAM the tub. Same procedure as you would use for a pool where you elevate the FC level to the recommended shock level based on your CYA and MAINTAIN that FC until you pass the procedure criteria. See the link in my signature for SLAM Procedure. However, your DPD test kit will not be able to measure the FC levels needed to complete the SLAM procedure as I'm sure your DPD test goes up to 10 ppm FC at the most, where the FAS-DPD will go up to 50 ppm FC. There's the difficulty as you can't truly complete a SLAM without a FAS-DPD test kit.
    2. Purchase a spa deep clean product. I HIGHLY recommend Ahh-some spa and jetted tub cleaner. This will remove residual biofilms that have likely accumulated in your spa plumbing based on the foam your are seeing. Perform the spa deep clean procedure using your existing spa water. Drain and repeat if you get a lot of scum and extreme grossness that Ahh-some will remove from deep in your plumbing. It's astonishing what comes out and how well it works. I'd also remove your filter from the housing and throw it in the middle of the tub when doing the treatment. Then refill and start with fresh water and certainly fresher plumbing. This option 2 is your best option, in my opinion.
    OK thanks for the info. I'll attempt the slam process also might look into getting the fas dpd test. Already blew another 20 getting reagents to test CYA and CH. Wish I just got the k2006 in the first place.

    It's about 4 months since last refill. I have used a product called spa purge last year which did a pretty good job. A bit expensive at $40 for one time use may give yours a look.

    Anyway, I added a pic to my second post if it makes any difference. Thanks again
    Intex 15'x48" AG metal frame pool (4,440 gal), Krystal Clear (1600) 14" sand filter, Taylor K2006 test kit, Intex Deluxe Maintenance Kit/vacuum (love it!), Intex Deluxe Skimmer, BBB.

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    Mod Squad JVTrain's Avatar
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    Re: Foam in back of filter

    4 months is quite a while since your last refill if you're using the spa regularly. 3 months is a good length of time on a well-used spa. You're due for a refill.

    You can get ahh-some on amazon for about $30 for a 2 oz container. This would likely give you 4 treatments, depending on the size of your spa. The 6 oz container is a better value for $50, but you may not need that many uses in the near future. It's far and away better than any other spa deep cleaning product that has been used by folks on this site.

    The hard part of trying a SLAM without a FAS-DPD is that you don't know if you're getting your FC high enough or too high and you don't know if you're maintaining the proper FC and you can't properly measure the FC at elevated levels to complete the last step, the OCLT. It would be more like a shock (and pray) and maintain (and pray) procedure. It may work out for you, but it's certainly not a recommended way to reliably deal with the problem.

    The pic doesn't look too bad, but that's after you had cleaned it out.

    Keep in mind, at your 50 ppm CYA, you should always have the FC above 3 and periodically be shocking the spa up to over 12 ppm FC. I say over because if you're using the information from the "How do I use chlorine in my spa" sticky thread, the recommended CYA level is 30 ppm. At 50 ppm, you need more FC to achieve the same level of sanitation.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: Foam in back of filter

    Quote Originally Posted by JVTrain View Post
    4 months is quite a while since your last refill if you're using the spa regularly. 3 months is a good length of time on a well-used spa. You're due for a refill.

    You can get ahh-some on amazon for about $30 for a 2 oz container. This would likely give you 4 treatments, depending on the size of your spa. The 6 oz container is a better value for $50, but you may not need that many uses in the near future. It's far and away better than any other spa deep cleaning product that has been used by folks on this site.

    The hard part of trying a SLAM without a FAS-DPD is that you don't know if you're getting your FC high enough or too high and you don't know if you're maintaining the proper FC and you can't properly measure the FC at elevated levels to complete the last step, the OCLT. It would be more like a shock (and pray) and maintain (and pray) procedure. It may work out for you, but it's certainly not a recommended way to reliably deal with the problem.

    The pic doesn't look too bad, but that's after you had cleaned it out.

    Keep in mind, at your 50 ppm CYA, you should always have the FC above 3 and periodically be shocking the spa up to over 12 ppm FC. I say over because if you're using the information from the "How do I use chlorine in my spa" sticky thread, the recommended CYA level is 30 ppm. At 50 ppm, you need more FC to achieve the same level of sanitation.
    Quick question about the chlorine test.

    I have the chlorine test where you add 5 drops of R-001 and R-002, cap, invert, match color. The test tops out at 5 ppm. If my shock level is 20, wouldn't I be able to use 1 drop of each and multiply the results by 5 to test high levels of chlorine up to 25? Or would this not work the way I'm expecting.
    Intex 15'x48" AG metal frame pool (4,440 gal), Krystal Clear (1600) 14" sand filter, Taylor K2006 test kit, Intex Deluxe Maintenance Kit/vacuum (love it!), Intex Deluxe Skimmer, BBB.

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    Re: Foam in back of filter

    If you're going to fudge the test to try to get a result for higher FC levels, you're better off diluting your pool water then using that to fill the cylinder. For instance, taking 200 mL of pool water and diluting it to 1 liter, then using that water to fill the tube to give a 5x dilution.

    However, when you do this the resolution of your test goes from 1 ppm to 5 ppm. That is, you can only tell the difference between 15 and 20 ppm or 5 and 10 ppm. Also, if you use a small volume of water to dilute, such as 1 mL into 5 mL of water, there is greater error introduced than if you dilute a larger volume of pool water. Again, it's an educated guess at best and not sufficient to properly complete a SLAM procedure. If you go down this road to attempt to solve your problems, your chance of success is much lower than if you do it properly with a FAS-DPD test. Everyone's out to save a buck, but sometimes saving a few bucks ends up costing your hundreds or worse, health problems.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: Foam in back of filter

    Quote Originally Posted by JVTrain View Post
    If you're going to fudge the test to try to get a result for higher FC levels, you're better off diluting your pool water then using that to fill the cylinder. For instance, taking 200 mL of pool water and diluting it to 1 liter, then using that water to fill the tube to give a 5x dilution.

    However, when you do this the resolution of your test goes from 1 ppm to 5 ppm. That is, you can only tell the difference between 15 and 20 ppm or 5 and 10 ppm. Also, if you use a small volume of water to dilute, such as 1 mL into 5 mL of water, there is greater error introduced than if you dilute a larger volume of pool water. Again, it's an educated guess at best and not sufficient to properly complete a SLAM procedure. If you go down this road to attempt to solve your problems, your chance of success is much lower than if you do it properly with a FAS-DPD test. Everyone's out to save a buck, but sometimes saving a few bucks ends up costing your hundreds or worse, health problems.
    Yeah my theory didn't work out. I raised the spa to shock level and tried 1 drop of each and got no color.

    Gonna give the diluting a try. Will probably end up refilling but worth a shot since my hoses are frozen right now.

    Anyway thanks a ton for the thorough explanations I swear u guys are better helpers than the pool and spa store.
    Intex 15'x48" AG metal frame pool (4,440 gal), Krystal Clear (1600) 14" sand filter, Taylor K2006 test kit, Intex Deluxe Maintenance Kit/vacuum (love it!), Intex Deluxe Skimmer, BBB.

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    Re: Foam in back of filter

    I was wondering about your location for that reason. Right now if I had to drain and refill my spa, it would be a real pain in the @$$. First getting it to drain and then trying to refill with temps in the single digits... not fun. I try to do a drain/refill in late October/November whether I need it or not, just so I have a better chance of having good water as long as I maintain it well through March.

    Good luck!
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: Foam in back of filter

    Quote Originally Posted by JVTrain View Post
    I was wondering about your location for that reason. Right now if I had to drain and refill my spa, it would be a real pain in the @$$. First getting it to drain and then trying to refill with temps in the single digits... not fun. I try to do a drain/refill in late October/November whether I need it or not, just so I have a better chance of having good water as long as I maintain it well through March.

    Good luck!
    Yep phili suburbs. Weather is really all over the place lately. I'm sure I'll get a 40 degree day soon and I'll be taking full advantage of it.

    I shocked to 20 ppm FC (using poolmath numbers) and the foam is a lot less today. It's honestly not that big of a deal since everything else is perfect, crystal clear water no odor. Chlorine usage is a little high though. After shock and no use FC was down to 1 ppm in about 20-22 hrs.

    Do phosphates play any role in FC consumption? I remember a few years back I tested high levels of phosphates and use a product to remove some and chlorine usage dropped a lot.
    Intex 15'x48" AG metal frame pool (4,440 gal), Krystal Clear (1600) 14" sand filter, Taylor K2006 test kit, Intex Deluxe Maintenance Kit/vacuum (love it!), Intex Deluxe Skimmer, BBB.

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    Re: Foam in back of filter

    Quote Originally Posted by spanoob9 View Post

    I shocked to 20 ppm FC (using poolmath numbers) and the foam is a lot less today. It's honestly not that big of a deal since everything else is perfect, crystal clear water no odor. Chlorine usage is a little high though. After shock and no use FC was down to 1 ppm in about 20-22 hrs.

    Do phosphates play any role in FC consumption? I remember a few years back I tested high levels of phosphates and use a product to remove some and chlorine usage dropped a lot.
    Losing that much FC is common when you have active algae and or bacteria, especially in a higher temperature situation like a spa. Keep bringing the FC up there until it sticks there. You might not have color or odor but there is certainly something consuming all that FC, likely you have some algae or bacteria growth on your filter. I'd remove it, spray it off well and soak overnight in a 5 gallon bucket of warm/hot water and dishwasher soap rinse and reinstall.

    There's lots of discussion on the topic of phosphates so feel free to search the site. The long and short of it is: phosphates are indeed algae food. However, if there is no algae present, phosphates do not matter. Maintain proper FC levels to prevent algae growth and phosphates don't matter. People who insist on maintaining lower than TFP recommended FC levels can use phosphate removers as insurance against algae. Phosphate removers are very expensive and simply maintaining proper FC levels is cheaper and more reliable.
    Last edited by JVTrain; 01-15-2016 at 10:30 AM. Reason: ADDED DISHWASHER SOAP AS I INTENDED.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: Foam in back of filter

    Quote Originally Posted by JVTrain View Post
    Losing that much FC is common when you have active algae and or bacteria, especially in a higher temperature situation like a spa. Keep bringing the FC up there until it sticks there. You might not have color or odor but there is certainly something consuming all that FC, likely you have some algae or bacteria growth on your filter. I'd remove it, spray it off well and soak overnight in a 5 gallon bucket of warm/hot water and dishwasher soap rinse and reinstall.

    There's lots of discussion on the topic of phosphates so feel free to search the site. The long and short of it is: phosphates are indeed algae food. However, if there is no algae present, phosphates do not matter. Maintain proper FC levels to prevent algae growth and phosphates don't matter. People who insist on maintaining lower than TFP recommended FC levels can use phosphate removers as insurance against algae. Phosphate removers are very expensive and simply maintaining proper FC levels is cheaper and more reliable.
    Shocked again to 20 last night and chlorine reserve is improving. About 5 ppm left this morning.

    Also cleaned filters today and there was some algae build up on the inner filter. Still getting the nasty foam in the back of filter bucket but it is getting smaller.

    Also forgot to mention that I do have an ozonator but the cartridge hasn't been changed or serviced in at least 5 years. I get the bubbles coming from the return jet but not sure if its just air from the injector or actual ozone. I did read your post in the thread regarding ozones and figured that might account for some of the FC loss.
    Intex 15'x48" AG metal frame pool (4,440 gal), Krystal Clear (1600) 14" sand filter, Taylor K2006 test kit, Intex Deluxe Maintenance Kit/vacuum (love it!), Intex Deluxe Skimmer, BBB.

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