Can't Get Rid Of Pollen

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D

deanr

0
Bronze Supporter
Jun 18, 2014
21
Wadsworth, OH
Pool Size
17500
Surface
Vinyl
Chlorine
Liquid Chlorine
Hi all,

I inherited a 27ft above ground pool when we moved here (Northeast OH) a couple years ago, roughly 17.5k gallons. This has a single cartridge filter system with a Jacuzzi 1HP, two speed pump. I have to confess I don't run the pump much (a few hours once a week maybe).

Last year I came across TFP, and have been following the BBB method ever since with good success. The pool sits in a shady area with trees on three sides. Normally, the only problem I have is complaints about water temperature (I'm pretty happy if I can keep it above 80F the last couple years even with the solar cover we keep on it all the time). The pool hasn't gotten a lot of use due to the cool weather we had this summer.

This summer, I've developed what appears to be a pollen problem. There is a yellow/brown powdery substance that collects on the bottom of the pool (only bottom, not sides). I'm nearly certain this isn't algae as I never let the FC fall below about 3ppm (Taylor FAS-DPD kit), CYA ~30. Water is crystal clear, except for the pool bottom. There is virtually no chlorine load - I lose none overnight and only a little during the day even if the pool is uncovered (remember, this is a fairly shady area and is in shade from early afternoon on). I vacuum it up, and a couple days later it is back. If I run the pump overnight, next morning it is in clumps on the pool bottom.

In desperation, I treated for mustard algae - I raised FC to 18ppm, vacuumed and a couple days later the pollen was back with the chlorine still at 16ppm. I can't believe this could possibly be algae at those chlorine levels (CYA 30ppm), so I'm convinced it must be pollen.

For whatever reason, my cartridge filter doesn't appear to be catching this when I vacuum - I can see it coming back out the return. It does catch some, if I open up the filter when I'm done, the water is yellow. But there is a lot that comes right back into the pool. I've tried putting on skimmer socks when vacuuming, but that doesn't help at all. They catch bigger things, but the pollen goes right through - maybe too high pressure?

I've about reached the breaking point - tonight there was so much on the bottom that when vacuuming it clouded up the pool with everything streaming back out the return. I don't know if there is a problem with the cartridge filter, or if pollen is normally this difficult to vacuum out. Perhaps if I ran the filter on low 24/7 it would pick up more and not pull it through the filter.

Any suggestions? Would flocullant or clarifier work to make these particles big enough to catch them in the filter or skimmer sock?

Thanks!
Dean
 
Deanr, when you touch this stuff does it poof up and disappear ? If you haven't noticed try it and see if just disappears when it's touched. If it does it's dead algae.
Your filter should be able to catch pollen along with the skimmer sock catching it. I know my skimmer sock catches pollen. Like was mentioned above check all the pleats for tears.
You stated you never let your FC fall below 3, good thing, but what is the level you target when you dose with chlorine ? What are you using for chlorine ? Do you test for CC and what is that result ? Better yet post up a full set of test results and what test kit you use.
You need to be running your pump more. At least 4-6 hours a day. If you don't your chlorine will not be mixed with the water properly if you only run it once a week. Plus not filtering the water properly. Not a good thing. Could cause algae to start to form and your FC kills it off before it can get a good foot hold. ?
 
As pwrstrk mentioned, you need to run your filter daily and not a few hours once a week. The pool needs to be turned over at least one time a day regardless of normal FC levels.
 
Do you have a vacuum to waste option? I vacuum by siphon over the side of my pool, don't even use the pump/filter since it is so small. You do have to move slow but if it isn't getting filtered this should help. although as other have stated, you do need to run your system more - at least a few hours daily.

I wonder if your cartridge is ripped or not set in the container correctly.
 
The cartridge filter itself is in its second year. I don't know of any tears in the pleats, but haven't checked each one thoroughly. I've never thought the cartridge fit well on the post it sits on - I've always suspected water could flow around it. Perhaps that is part of the problem.

I know I need to run the filter more - I had thought with such low use and nothing in the pool (no ladder even) that the chlorine would stay mixed. If that isn't the case, then I can see how there could be areas where algae could start to form.

I use liquid chlorine, 12.5%. I typically put in about half a gallon every few days in the summer, which raises it about 3.5ppm at a time (tend to lose 1ppm/day). It's lasting longer now that I'm getting less sun. I haven't checked CC in a long time as I've never measured any after the initial work opening the pool. I had thought that if there was no real chlorine load, that would be an indicator that there is no algae in the pool. Is that a correct statement, or am I missing something?

I'm using a Taylor K2006 kit.
FC=6ppm
CC=?? (haven't measured in a long time)
pH=7.3
TA=110
CH=500
CYA=30

- - - Updated - - -

One other question - I have a two speed pump. If I run the pump overnight, do I need to run on high speed or is low speed ok?
 
You can run your pump on low speed most of the time. I only use high speed when I vacuum, mix bleach additions or if I need the water to be skimmed better.
One other thing is to make sure you run your pump 30-40 min's prior to taking any tests to make sure water is mixed well. You can do that that on high also.?
 
Thanks!!

Any thoughts on my theory that if there isn't a significant chlorine load (less than 1ppm drop per day), then I must not be having an algae problem?
 
It could very well be just pollen. Try touching it with something, your foot, brush, carefully and if it poofs into a cloud and disappears it's dead algae. If it doesn't I'd say it's pollen, silt, something along those lines.
If your using an FAS/DPD test kit you could do an OCLT Test. Bring your FC up to 10 at night and confirm it's at 10. Then in the morning test your FC before the sun hits the pool. Let your pump run the whole time at night. If you lose 1 ppm or less your good. ?
 
I hit the debris with a brush; it took a harder hit then just a touch to make it react. But when it did, it poofed to barely visible powder floating in the water.

Until a couple days ago, the water has always been very clear, with the exception of the debris on the bottom (this has been going on for a couple months). This last time the debris level on the bottom was much heavier. When I vacuumed and saw all the debris coming back out of the return the water turned cloudy. I attributed that to the debris floating in the water. Could have been but when I turned the pump off it didn't settle overnight - the water is no longer clear like it always had been. Now it definitely looks like an algae bloom starting.

I removed the solar cover a couple days ago in preparation for closing the pool (which I can't do until I get this problem cleared up). I checked the CYA level today, and this time I got levels somewhere between 40-55ppm!

I've always had a difficult time with this test; I prefer precise, repeatable numbers in my measurements. I haven't checked this number since mid summer, when I was consistently getting readings around 30ppm. Since I use only liquid chlorine, I expected the CYA to go down over the summer, not up. I was quite surprised with these numbers, so I repeated the test several times (same solution, just kept pouring it back and forth over an hour or so). Each time, I got a value of ~55ppm at first reading, thought that couldn't be possible, looked again and thought I could still see the dot. I'd keep dropping until I was sure the dot was gone, usually around 40ppm.

If the CYA level really is around 50ppm, then it had to be at least that high all summer and I've been running FC levels too low all this time. Perhaps that could explain why my FC levels haven't been dropping as quickly on the low end as I had expected.

Today I SLAMed the pool, taking FC up to 22ppm. I'll hold it there until this clears up, then plan to close the pool along with some Polyquat 60.

Any thoughts on the CYA reading? At the beginning of the summer I had no measurable CYA, and an extremely high chlorine load. I had to add CYA, I put in enough to get up to about the 30ppm level that I was reading. I took readings for several weeks after, but perhaps it took longer to dissolve than I expected. Or perhaps the reading now is bogus. The water is cold now with the cover off (66 degrees), not sure how that might effect the reading...

If there are any best practices on measuring CYA, I'd appreciate them. I really dislike subjective readings! I guess I should get a reference solution to see what it should look like, that would at least help...

Thanks!
 

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Your doing the right thing with a SLAM. It'll go quick. Just follow the process to the T as described in Pool School. Your done when
1 water is crystal clear
2 CC of 0.5 or less
3 pass the OCLT
I think there were a couple of factors that led to this lack of pump runtime, low FC and the misinterpretation of the CYA level. Now you'll know better.
The comparative test might not be a bad idea if your having trouble with the CYA test. Was it a sunny day when you tested and did you have your back to the sun and test vial at waist height ?
Is still take a look at your filter for problems. Stuff shouldn't be getting blown back into the pool. ?
 
I've tried to be consistent about testing the CYA when it is sunny, and keeping the sun to my back (meaning the measurement is taken in the shadow of my body at waist height). I'm not sure what I did differently this time, other than the water temp is probably lower. I faintly remember reading somewhere that water temp needs to be at least 70? But I doubt it made that much difference today.

In any case, I've learned a few things.

Thanks!!
 
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