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Chlorine lock mystery

Created by Harrow Harrow  > 9 months ago, 11 Jan 2016
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Harrow
Harrow

NSW

4521 posts

11 Jan 2016 4:41pm
Pool has quite a tinge of green to it that I just can't budge. Test kit shows 10ppm of chlorine, and 300ppm of stabiliser, and pH is mid 7's.

Typical chlorine lock scenario....except....I haven't added stabiliser or stabilised chlorine for years (pool is shaded most the day, so don't really need it) and I've done quite a few filter backflush pump outs with the heavy rain we've had recently.

How is this possible?


felixdcat
felixdcat

WA

3519 posts

11 Jan 2016 1:52pm
Add yellow to blue and what do you get? Stop peeing in it!
Harrow
Harrow

NSW

4521 posts

11 Jan 2016 5:15pm
At least you didn't say I need more downhaul.
adolf
adolf

1862 posts

11 Jan 2016 2:22pm
Chuck some more chems into it and run the filter until it's clear
Zachery
Zachery

597 posts

11 Jan 2016 4:42pm
most local hardware shops do tthe free test then sell u what u need, but from my younger kid days i think it was a small amount of hydrachloric acid to remove the algae from water , no swimming for one hour filter on!!! please check said advise been awhile!!!
bazell
bazell

NSW

120 posts

11 Jan 2016 7:57pm
Been having the same problem all season. Filter was clagged so replaced the beads then hit it with cloud out and acid and finally its clean.

Hate that bloody pool but Mrs won't let me fill it in

MDSXR6T
MDSXR6T

WA

1019 posts

11 Jan 2016 5:26pm
How are your phosphate levels?
Chris6791
Chris6791

WA

3271 posts

11 Jan 2016 5:46pm
Select to expand quote
bazell said..
Been having the same problem all season. Filter was clagged so replaced the beads then hit it with cloud out and acid and finally its clean.

Hate that bloody pool but Mrs won't let me fill it in



They make a great Koi pond. Technically it's not being filled in...
Battle
Battle

536 posts

11 Jan 2016 8:59pm
Give up and go live in a van.
Harrow
Harrow

NSW

4521 posts

12 Jan 2016 12:56am
Select to expand quote
MDSXR6T said..
How are your phosphate levels?


Probably through the roof as I have a dozen 20m gum trees all around the pool.

But what I really want to know is how I have isocyanuric acid levels 20 times the recommended level, WHEN I'VE NEVER PUT ANY IN THE POOL!!!???

MDSXR6T
MDSXR6T

WA

1019 posts

11 Jan 2016 11:01pm
What chlorine are you using? Liquid, granular or tablets?

Are you sure the test is accurate or your not confusing the CYA test with water hardness? The tablets used in home / tube style tests can be somewhat inaccurate.
Elroy Jetson
Elroy Jetson

WA

706 posts

12 Jan 2016 12:02am
Your pool is an ecosystem. Over time the bacteria and Algae in the pool can develop a resistance to 'normal' levels of Chlorine. Evolution is happening in your backyard and its time for a super chlorination.

The short term higher levels of chlorine kills everything in the pool. Don't swim in the pool for a few days or until the Chlorine level returns to a normal level.
JulianRoss
JulianRoss

WA

544 posts

12 Jan 2016 11:17am
.... sounds like chemtrails to me....
Loftywinds
Loftywinds

QLD

2060 posts

12 Jan 2016 2:43pm
I had the same issue. Solved it by salt saturating it, heaps of filter and a good 5 minute backwash to clean the filter, followed by 2 litres of HydroChloric acid.
Done
Harrow
Harrow

NSW

4521 posts

12 Jan 2016 8:58pm
The chlorine bomb has been dropped. We'll see what remains in the morning. Got 4 gallons of brickies acid in the garage to deal with the aftermath.
lungs
lungs

QLD

492 posts

12 Jan 2016 9:28pm
If the stabiliser level is correct (most off the shelf test kits won't test for stabilizer, its not alkalinity or hardness by any chance) then its way too high, 100 max but works best between 25 to 50. the higher the stabiliser the more free chlorine you need. Take a sample to a pool shop, but be wary when they try to sell u stuff, make up a story that you have most of it and need to check the shed etc. etc. then source it elsewhere cheaper.
You need to distinguish between free chlorine and total chlorine as free chlorine does the killing/oxidizing. Get Alkalinity correct then Ph then Liquid chlorine (its cheapest) run filter continuously until it clears up. You really do need to get a full test done to find out what's going on. Could be copper from algaecide, crappy filter or heaps of other reasons. This link is pretty good.


www.troublefreepool.com/blog/
Harrow
Harrow

NSW

4521 posts

12 Jan 2016 11:08pm
Select to expand quote
lungs said..
If the stabiliser level is correct (most off the shelf test kits won't test for stabilizer, its not alkalinity or hardness by any chance) then its way too high, 100 max but works best between 25 to 50. the higher the stabiliser the more free chlorine you need.

www.troublefreepool.com/blog/


Thanks for the link, it looks interesting. I'll check it out.

This is what I'm using, it checks for cyanuric acid. www.aquachek.com/retailer/aquachek-yellow-4-in-1/

I know 300 is ridiculously high. What I am really wondering is if anyone can tell me what would cause my kit to show 300ppm when I haven't added stabiliser or used stabilised chlorine for almost a decade. Any ideas, it's a damn mystery to me!!!

Edit...I thought I knew my pool chemistry, but after reading the link you posted, I only knew about half the story. Thanks!
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