Having problems with Green Algae coming back over and over and.........

JoyfulNoise

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May 23, 2015
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Rob,

If you can, it might be helpful to check the nutrient levels in your water. Water high in phosphates and nitrates can make it hard to maintain a clean pool because any dip below the recommended FC levels will give algae a chance to grow. If your water is particularly rich in nutrients, then that slight chance of growth gets enhanced by a favorable "food" environment.

Normally we always say that phosphates are irrelevant and that is true in 99.9% of the pools out there. Your situation seems unique in that you are reporting constant algae outbreaks even though you've completed SLAMs and seem to hold to the proper FC/CYA ratios. Maintaining the proper FC/CYA ratio will always kill algae but excess nutrients just make it harder if you happen to slip up.

It's not urgent to get the tests done, but at some point when it's convenient you might stop by a pool shop and ask them to check your nitrate and phosphate levels. If they are relatively normal, then that ends this idea. But if one or both are very high, remediation of the water with respect to them may be required to get you to a place where you not trying to balance on the head of a pin.


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006
 

Docker_rob

Active member
Feb 7, 2015
43
Perth - Australia
Hi guys, first to clarify yes I have slam'd with FC up over 28 for a couple of days now. Cc is below 0.5 and I just need to complete my overnight test but I am sure that is more a formality.

Matt re the phosphates thing. 12 months ago I was told my phosphates were high and the pool shop sold me some "potion" to use. After readng here I thought that was a con so although I used the product I left it at that.

But being they said it was high once maybe it is high again. I will take a sample to be checked. Visually My water is 100% at the moment although chlorine will be high. Will phosphates still show up after a slam?

And the test says I am high in phosphates, so do I buy the pool shop stuff? I recall it was very expensive so maybe their are alternatives?
 

JoyfulNoise

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A properly done phosphate test should not be affected by chlorine. All I would do is get the pool store to test for phosphates and nitrates (if available). Do not buy anything and simply ignore their advice. Post results here when you get them.


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006
 

Docker_rob

Active member
Feb 7, 2015
43
Perth - Australia
(Per post #17). FC of 5 (or even 10) is not shock level.

Hi Marian, I think you are confusing my results I posted in #1 which were Pre-Slam results. At that time I had FC of 5 but murky water on its way to swampsville :)

I ran my SLAM at or over a FC level of 28 based on my CYA of about 65

I am going to head to the Pool store now and ask for the Nutrient test.
 

MarianParoo

Well-known member
Aug 16, 2014
4,612
Northern IL
.
Nope, this was the one that confused me:

Hi guys, after all this I am leaning towards keeping my FC levels higher than what the K1000 test can measure. (Only goes to 5ppm and that's the min of what I am aiming for)

So instead of using reagent test all the time (which I will run out of and supplies near me are not available) is there either another suitable day to day test kit I can use that say measures up to 10ppm?

Or is it feasible to dilute the sample say 50% and still use the K1000 kit for my day to day testing?

Perhaps you were meaning post-slam? If so, how are you testing to 28ppm NOW during your slam?

I apologize if I misread your intent. Good luck with everything.
 

Docker_rob

Active member
Feb 7, 2015
43
Perth - Australia
Hi all, Just back from the Pool shop and I finally feel we may be getting somewhere.

The pool store ran a phosphate test with a kit where they look for a colour change from Clear to Blue to indicate phosphate level. Their test kit scale went from 0 through to 1.0 ppm in 0.2ppm increments. with 1.0ppm being the highest they could measure. Anyway my result was 1.0 ppm (or possibly higher as it doesn't read higher than that n the scale they used)

I didn't buy any products but we chatted about a product called "Starver" and being I have had this issue ongoing they were talking about the need to possibly incorporate ongoing phosphate control into my monthly routine. Here's a link to the product they recommended - STARVER LIQUID 5LTR

I Look forward to hearing back what you think I should do. :thumleft:

Cheers.....Rob
 

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Docker_rob

Active member
Feb 7, 2015
43
Perth - Australia
Thanks Chem Geek - yes I do have the TF-100 (which includes the K1000)

Up until now I had been using the K1000 for regular FC checks a couple of times a week, and the TF100 with R0871 reagent less frequently (maybe every 1 - 2 weeks). to get a more accurate number. Last 2 SLAM's I have been chewing through the R0871 reagent (with FC levels above 30 it takes a lot of drops) so I was keen to use that sparingly as I will run out and getting supplies (although reagent is cheap) the freight is a killer for me. Hence I thought I could use the other kit for more regular day to day testing to make sure I wasn't getting too low on my FC levels.

You also mentioned water circulation may be less than ideal. This is very possible if not probable especially when I have my Pool blanket on for extended periods. When on the skimmer doesn't really work and if on for a few days leaves and the like get in and are not skimmed off. and more load on the FC I presume.

Anyway not to worry, from the sounds of it I probably have a few things contributing to these outbreaks. 2 (maybe 3) choices moving forward.

1 - Keep my FC level at a higher level (Must be something higher than 5 as I had an outbreak start to kick off at that level)

OR

2 - Use one of those Phosphate remover products

And possibly 3

Use the pool blanket less or take it off more regularly


If I was going to go with option # 1 would there be a FC level / range I can aim for is it it purely trial and error?

Or is Option # 2 likely better for me?

Thanks again everyone for your help. I've learnt a lot.

Rob
 

JoyfulNoise

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May 23, 2015
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I would suggest you maintain the higher FC and not go chasing down too many rabbit trails with phosphates. 1000ppb is the upper limit of most tests and so the sample should have been diluted to find the proper value. That said, my phosphates are high the last time I checked (750ppb) but my water is fine. And that number is "high" by pool store standards which is just their means of justifying the sale of expensive chemicals.

I think the real problem here is poor circulation, a pool that is probably covered too much and inaccurate testing. I, personally speaking, think the OTO yellow chlorine test is worthless and inaccurate and I have never gotten it to read properly. I much prefer to use the DPD chlorine test chemistry. And I think you need to use the more accurate FAS-DPD test much more frequently than you are now as I'm pretty sure what's going on here is your FC is dipping too low. That gives the algae a chance to grow and then your back to green.


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006
 

chem geek

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Mar 28, 2007
12,083
San Rafael, CA USA
Last 2 SLAM's I have been chewing through the R0871 reagent (with FC levels above 30 it takes a lot of drops) so I was keen to use that sparingly as I will run out and getting supplies (although reagent is cheap) the freight is a killer for me.

During a SLAM you can use a 5 ml sample size where each FAS drop represents 1 ppm. That will save on reagent. For normal testing, using the 10 ml sample size for 0.5 ppm resolution should be sufficient. The OTO test can be hard to read, but I hear you regarding the cost of getting the FAS-DPD reagents to you.

As for the FC/CYA level, yes it's trial-and-error in your case. You could see what a 10% ratio does so at 65 ppm CYA that would be 6.5 ppm FC. The downside with this approach is that you lose more chlorine to sunlight so it costs more in chlorine.

Is your vinyl liner blue? If so, then yellow pollen on a blue background looks green so are you sure you don't have pollen? Have you tried using a skimmer sock to see if it collects anything?
 

Docker_rob

Active member
Feb 7, 2015
43
Perth - Australia
During a SLAM you can use a 5 ml sample size where each FAS drop represents 1 ppm.

As for the FC/CYA level, yes it's trial-and-error in your case. You could see what a 10% ratio does so at 65 ppm CYA that would be 6.5 ppm FC. The downside with this approach is that you lose more chlorine to sunlight so it costs more in chlorine.

Is your vinyl liner blue? If so, then yellow pollen on a blue background looks green so are you sure you don't have pollen? Have you tried using a skimmer sock to see if it collects anything?

Hi chem geek, Yes my liner is blue, but I am 99% sure it is algae as when I have had to scrub off fittings they have been green. Thanks for the 5ml sample size tip, that will help a lot.

As for moving forward I am in 2 minds at the moment which way to go (maybe it's a bit of both) Chlorine use is not so much an issue as I have an SWG so, just need to notch that up a bit, but.....

If I keep my FC around say the 7ppm and I had an outbreak kick off at about the 5ppm level, I don't have a lot of leeway for error. As my pool is not big, a high bather load could knock that FC down a couple of points quickly or If I added too much CYA one day, there again I'm really sitting on a knife edge. (Maybe in reality that's what it is for everyone though I'm not sure)

If I go the Phos remover route and get phosphate down to a more manageable level, once treated is that likely to be it for a little while until it builds up again? Or is this just likely going to be a much shorter fix? i.e Will it be back to haunt me sooner than it's worth?

I'm thinking if it improved things for say 6 months from one or 2 Phos treatments, then that's not too bad and gives me a bit of extra leeway on my FC levels. I will then need to monitor that phosphate levelvia the pool store more regularly to stay ahead of the curve. (In all honesty that has only been measured twice in 3 years and one of those times was yesterday)

Decisions decisions......
 

JoyfulNoise

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May 23, 2015
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Don't know about Australia but here in the US there are several phosphate test kits. I have one by AquaCheck which was pretty cheap (~$10 US) and it reads 0-1000ppb in 250ppb increments. I believe Taylor retails a similar test. If you are serious about phosphates, then you should get a test kit for it so you can confirm that any phosphate remover product you use is indeed working. As you know, pool store testing is often way off.

By the way, does your liner have any seams? Algae loves to hide in liner seams.


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006
 

chem geek

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Mar 28, 2007
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San Rafael, CA USA
The phosphate remover should let you operate at lower FC/CYA levels or for your pool the normal levels and not get algae growth. Even if you have significant phosphate levels in your fill water it will take time for that to climb unless you have very high amounts of evaporation and refill. Even so, the amount of phosphate remover needed won't be that high once you do the initial larger one-time dose to lower it. Note however that you can't use phosphate-based metal sequestrants such as HEDP since they break down to produce orthophosphate (a lot of orthophosphate depending on how much HEDP you use). If your' not using HEDP, then the only other significant source of phosphates would be blown-in fertilizer.
 

Docker_rob

Active member
Feb 7, 2015
43
Perth - Australia
Just thought I'd provide an update for all those who have helped here. I decided to add some Phosphate remover and ran the pump for the last 24 hours. During that time what looked like a "brown dust" had settled on the pool floor in patches. I've vacuumed it away and backwashed the filter.

I just had my Phosphate tested and now sitting at 0.6ppm (from somewhere north of 1.0ppm) so it's certainly come down.

I've added a little more phos remover, but hoping at these reduced levels and keeping my FC in the recommended ranges the chance of another outbreak will be greatly reduced.

In hindsight I now look back and I had fertilised my lawn 6 or so weeks ago. I'd say some of that granulated fertiliser has blown into the pool and may be the source of my problem. It's certainly something I will need to be mindful of next time I need to fertilise.



Cheers
 

Casey

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Fertilizing could very well have tipped your pool over to the green monster. Maybe next time wait til your wind blows away from your pool so you don't get it in there.
 

ping

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Jun 24, 2011
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Long Beach, CA
How often does the pool get brushed?

Has the cover been on during the SLAM to get exposed to the high FC? I would make sure it gets in the water at SLAM levels and then brush it completely down and inspect it for any signs of algae.

I would shoot for maintaining the FC at 7ppm this summer.
 

BuckeyeChris

Well-known member
Jan 28, 2014
824
Buckeye AZ
Keeping your pool a few ppm above the target FC ppm is not that big of a deal, and over the course of the year is still cheaper than using phosphate removers. It takes a bump to get up to that level, but to stay at your target each day will take almost the same amount of bleach.
 

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