Green pool

[mumgoa]

Hi guys

First off I am not a real pool geek. I own my 16 X 32 - 22K gallons gunite pool since 2014

I do not own a test kit (use test strips) but get my water tested without fail each week at the pool store. It has worked for me for the last 7 years

I had algae break out in 2014 and shocking got me clean pool within a few hours

Today, it seems to be a different situation:

Pool was crystal clear on Tuesday and water test was all good
Thursday, the pool is all green

I have had minor algae outbreaks maybe once or twice after 2014 and shocking has cleared it within a few hours

I put i one gallon of shock last night and 2 this morning with filter running since last evening at 5 PM and seems to have made no difference to the color

Got my water tested today (Friday) and except for high chlorine as expected all other chemicals are in balance

Filter gauge is at 23 (like always) and returns have a strong pressure

I was expecting a clearing pool when I woke this AM like it always has been but no such luck this time

Just put in some non chlorinating shock now and waiting

Thanks

 

[Donldson]

Since you mention that you don't have a test kit I'm guessing you know we're going to ask and require results from an appropriate one so that we can properly assist you in figuring out this issue. We don't do test strips, we don't do pool store testing, we need good data to work with and neither of those even comes close.

Test Kits Compared I highly recommend the TF-100 or Taylor k-2006c.

 

[mumgoa]

Thanks Donaldson

How do i know the sand filter is doing its job? It is strange to see clear water turn green in 2 days I would imagine

I have read threads that state sand does not really need to be changed

The pool I own is 7 years old and don't know hold old the sand is?

 

[Donldson]

It is strange to see clear water turn green in 2 days I would imagine

That would be indicative of an underlying algae issue that's just been waiting for the slightest chemistry problem to explode. Sand should not need replaced unless you regularly use items such as floc that can ruin its filtration capability, but that's definitely not the issue here. Filtration problems cause very slow cloudiness. They do not cause quickly appearing issues and they never cause green pools. Green pools are chemistry issues 100% of the time.

 

[mumgoa]

Thanks, sir. Great to know!

I will look into the test kits

 

[mumgoa]

I had a friendly neighbor help out. Per TF 100

FC = 25
CC - 10
TC = 25

Alkalinity = 90
CYA = 80

Does that tell us the reason?

 

[mumgoa]

WIth CYA high, sh

 

[mumgoa]

With high CYA should I start drain and filling in steps - using filter backwash?

 

[Donldson]

Your CC reading is incorrect due to the non-chlorine shock you added (that stuff is worthless in a residential pool, for future reference) so you'll need to ignore that for the time being.

Yes, you'll probably want to get your CYA level down. You're going to need to perform the SLAM Process to clear up the water, but unless your neighbor is going to let you borrow their kit for the duration you'll still need to get your own to manage the process. Test strips and pool store testing got your water in to this mess, I wouldn't continue to rely on them.

 

[mumgoa]

Thanks

I will order the TF 100 kit today

I drained about 4 inches of water and replacing that now

Will repeat a few times

Since the other chemical readings look OK, I will do the SLAM process once CYA level is 60 or lower

 

[mumgoa]

How much water should I be looking at replacing?

I will let the pump run all night and tomorrow I plan to do a second round of drain/refill

 

[Texas Splash]

How much water should I be looking at replacing?

That depends on how high the CYA actually is/was. Easy CYA math .... if the CYA was 150, then replacing half of the water would lower if by about half to 75. You should be able to lower more than just 3-4 inches at a time to protect from pop-out, but do what feels right for you and your local area (water table). But your goal of lowering the CYA to about 60 or below is good in preparation for the SLAM Process. You want that CYA under control first. Two other things:
- Please update your signature with all of your pool and equipment info (it helps)
- Are you on a well?

 

[mumgoa]

Thanks

I will order the TF 100 kit today

I drained about 4 inches of water and replacing that now

Will repeat a few times

Since the other chemical readings look OK, I will do the SLAM process once CYA level is 60 or lower

That depends on how high the CYA actually is/was. Easy CYA math .... if the CYA was 150, then replacing half of the water would lower if by about half to 75. You should be able to lower more than just 3-4 inches at a time to protect from pop-out, but do what feels right for you and your local area (water table). But your goal of lowering the CYA to about 60 or below is good in preparation for the SLAM Process. You want that CYA under control first. Two other things:
- Please update your signature with all of your pool and equipment info (it helps)
- Are you on a well?

Hey

thanks
Not on a well

will update signature

well, some progress on the issue. If i am not imagining things the green is a lot less dark and in between green and cloudy. CNA is now at 55

FC is high at 32

I drained and refilled 10 inches

not adding any more shock due to high FC level

fingers crossed

 

[mumgoa]

I want to drain/refill another cycle

For draining user filter, should I use backwash or waste? I intend to drain abut 2-3 feet

Thanks

 

[Texas Splash]

should I use backwash or waste?

Either is fine. f you think the filter is dirty and needs a cleaning, backwash will work.

 

[mumgoa]

Thanks TX

The color is green to cloudy all day. No further discernible improvements. Looks like fresh water has helped but not quite enough yet. That is why I plan to drain more tomorrow
Can't put more shock in as FC is 32

Anything else I need to do at this point?

Also, I plan to drain and refill about a foot more (not 2 feet)

Please suggest

Thanks so much, guys

This is the first time in 7 years i have this situation. Previous situations have resolved in a few hours with liquid shock

 

[mumgoa]

Also, should I run the pump overnight (it has run about 30 hours straight) since I plan to drain and refill and then have the pump go at a stretch after

 

[Texas Splash]

Best thing you can do at this point is get the CYA down to a point you are ready to start the SLAM Process. Are you still borrowing a friends TF-100? You're going to need quite a bit of reagents for your SLAM Process. With that you should be able to perform the SLAM Process properly. If you follow the notes on that page carefully, you should be able to overcome the algae issue.

 

[Texas Splash]

Might also be good for us to see a pic or two of your pool water from a couple different angles.

 

[Texas Splash]

Oh, and yes, the pump remains on 24/7 during the SLAM Process, but a low speed or rpm is fine. You just want continuous movement.