Algae at 8-10ppm?

Orion7319

Well-known member
Jul 1, 2020
1,287
Rock Hill, South Carolina
Pool Size
19775
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-15)
Earlier this month we left for vacation for a week. I had my father in law come by and skim the pool every day, but I didn’t show him how to use the robot. When I left the FC was 8 and my CYA was 60. I added a pound of Cal-Hypo as I was heading out the door and that should have brought the FC up to around 12. When we got back, I had leaves in the bottom of pool (obviously) and several spots of green algae. My FC was 10 and CYA 60 when I returned. My pool only gets a few hours a day of direct sunlight and is completely shaded or partially shaded all day except between 2:30 and 4:00pm when it’s mostly in the sun (which is why I haven’t upped my CYA to 70, FC seems to hold all day). I run my pump and salt cell 24/7. I monitored my pool via my blink cameras all week and it never rained while we were gone and the pool wasn’t used. This isn’t the first time I’ve had algae spots. Last week we got a ton of rain and salt and CYA levels dropped and the pool got a bit hazy. I noticed a thin layer of algae on the entire bottom of the pool, like a layer of dust gets kicked up when I brush it, so I started a slam last night. I don’t get though how I can up my chlorine to 12ppm, come home and find algae at 10ppm.
 
Some pools need to be brushed/robot/swam in often to keep from having localized algae. You must be in a high organics area.
 
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Some pools need to be brushed/robot/swam in often to keep from having localized algae. You must be in a high organics area.
Yep! My entire backyard gets covered in algae. Algae on the outdoor rugs, on the furniture, on the side of the fence. I have a gardenhose sprayer that I just use to spray bleach around and kill algae. I have tons of trees, and it’s been raining a lot more then usual. I am starting to wonder if I should sometimes use polyquat 60? I could also point my return in the deep end completely down as the spots usually only form in the deep end. I have a betta robot for skimming and only have two returns. Here is a pic of my pool at noon today. Always in the shade at noon.
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Polyquat 60 is likely not going to do much as the FC consumes it.
Surprisingly, for your situation, a phosphate test kit (your own) may be warranted. Only address if above 2000 ppm.

Also, any wrinkles in the liner? Those can be problematic.
 
Polyquat 60 is likely not going to do much as the FC consumes it.
Surprisingly, for your situation, a phosphate test kit (your own) may be warranted. Only address if above 2000 ppm.

Also, any wrinkles in the liner? Those can be problematic.
Ok thanks for the heads up on the polyquat 60. I do have a Taylor phosphate kit that I bought last month, but haven’t used it yet. I’ll test the phosphates once I get this slam done. One question about phosphate treatments if I need to address them? Will that gum up my sand filter? I do have some wrinkles in the shallow end due to a major leak in the gasket around the steps when they installed the liner, but no wrinkles in the deep end where I’m seeing the algae spots. This has to be an area of poor circulation.
 
The water is clear (but hasn’t regained its “sparkle” yet). Two nights ago I passed the overnight FC loss test, but I dumped in another gallon of 10% chlorine for good measure. I’m going to call this SLAM done and am now waiting for the FC to fall below 10 to measure for phosphates. We bought the house in August of 2019 and the pool went green during closing. Last year in August we had an algae bloom despite my daily testing and keeping the FC and CYA and everything else in range. It happened again just now. I am noticing that the large oak tree next to the pool seems to start dropping leaves and acorns at the tail end of July, and I’m starting to suspect that it has something to do with these August algae blooms I’m getting. If the phosphates test high, I will begin monitoring for them every summer when I start seeing acorns. Am I correct to assume that phosphates shouldn’t matter unless they exceed 2000ppm? At that point I am also going to assume that I don’t have to try and bring them down to 0, but somewhere below 2000? 1000 perhaps?? I don’t want to get too hung up on monitoring and treating for phosphates and only want resort to treating for them when they are exceedingly high if I can.
 
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Correct. Lower levels are of little consequence to a properly managed pool.
Just tested for phosphates. My FC is at 14, so that might skew the test a bit, but probably not that much. It tested for me at greater then 500 but less than 1000. The kit only goes to 500 then jumps to over 1000. I did have two significant rain events since I noticed the algae and I backwashed my filter this morning and refilled the pool before testing. One of the rain events almost overfilled my pool, and took 10 minutes to drain (I backwashed the filter for that long to give it a deep clean). How many ppm of phosphates could I have expected to be removed by dilution from rain events that I know that I lost 200ppm/40lbs of salt and around 10ppm of CYA from? More importantly at this point I take it that I shouldn’t be concerned where the phosphates levels are right now. I’m also going to play around with my returns and point them down towards the area where the algae formed. I have a skimmer robot so I’m not as concerned about flow towards the skimmer.
 
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Your water and environmental conditions are just more prone to algae than others. Diligent brushing, etc, should minimize the issue. Be sure to brush / disturb the areas the robot does not get to. Swimming works just as well as brushing.
 
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Your water and environmental conditions are just more prone to algae than others. Diligent brushing, etc, should minimize the issue. Be sure to brush / disturb the areas the robot does not get to. Swimming works just as well as brushing.
This pool gets leaves and dirt in it pretty much continuously. I have to skim the pool or blow leaves off the pool deck several times a day. I have figured out a few things that help. Getting the betta solar skimmer helped, running my pump and SWG 24/7 helps, running the robot a lot helps, adding DE to my sand filter helps. I never have to do long extensive slams on the pool, but I do have to do it a few times a year when I start to see algae at the bottom of the pool. I think I’m going to start bringing my pool up to slam level a few times a year, just to oxidize all the dirt and dissolving leaves I continually have.
 
You might look in to using up to 50 ppm of Borates in your pool. They may be enough to keep your minor algae issues at bay.
 
You might look in to using up to 50 ppm of Borates in your pool. They may be enough to keep your minor algae issues at bay.
I will look into that, thanks! I will probably wait until next year, though as our swim season will be over soon. In the meantime I will start reading up on it.
 
I guess a chainsaw is out of the question.
The main offenders are some pine trees that are on my neighbors side. The other main offender is a large oak. The oak is our favorite tree and if I wanted to take it down it’s going to be problematic. It’s very close to our house and our septic leach field. I don’t know how a tree company can get back there without risking the leach field. Also my neighbor (not the one with the pines) wants to take down an oak in her yard that’s pretty close to it. Apparently it’s going to cost her $8000.00 to take it down. I did just now take down a fairly large Mimosa tree that was dumping all kinds of stuff in the pool and was starting to get a bit close to the over head power lines. That was a job because I don’t own a chain saw. I resorted to using my 18v reciprocating saw on it. I have one more tree near the pool that I can manage to take down by myself I am trying to get my wife to let me buy this as I type this reply before I go after it :)
 
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It’s very close to our house and our septic leach field. I don’t know how a tree company can get back there without risking the leach field.

For these kind of trees, use a tree service that has a crane. I had 5 large sweetgums removed from my backyard this summer. One of them was within about 10 feet of my pool. They attach a cable to a section of tree, cut and lift the section over the house to the street. No heavy equipment in the backyard. It almost took them longer to set up the crane than it took the doing all the cutting. Once on the street, they cut off all the limbs and chip them. They cut the trunks in about 8-10 ft sections and bring in a log truck to remove them.
 
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