Chlorine loss problem

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K

Karlosw

Well-known member
Jan 9, 2023
55
Australia
Pool Size
55000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Astral Viron V25
Hi all.

I have joined in the hope that you all might be able to help with sorting the chlorine loss in my Pool.

Essentially over the last couple of months I have been constantly losing chlorine no matter the level of my chlorinator.

I have conducted two slams. The first with low stabilizer where I maintained chlorine level at 10pm for about a week until lost less than 1ppm over night and less than 1 combine chlorine. However within two days of completing this, chlorine dropped to 0 again.

Unfortunately during these two days I boosted stabilizer to 60- 70 ppm. I then did another slam with chlorine at 24 ppm. Again passed the over night test after about 5-6 days. With SWG set at 25% dropped to 5ppm chlorine over 5 days. I then increased SWG to 75% and maintained 4-5 ppm chlorine for two days. To increase chlorine levels I increased SWG to 100% but two days later was back at 0ppm chlorine!!!

I am at a loss for what is going on. Pre-solar heater I could have the SWG at about 40% and would be no problem. I got the solar heater two summers ago and had a similar problem but not to the same extent.

Any advice would be greatly appreciated.

Pool details are set out below.


Pool details:
Fibreglass
55000 liters
SWG V25 Viron with cell replaced 12 months ago. Running 12-13 hours a day
Pool cover used when not in the pool
Pool water temp at 30C with solar water heater

Cheers
 
Welcome to TFP.

I do not know the Viron SWG system. Does it use a flow switch or other flow sensing mechanism to turn itself off when it has low flow?

I suspect that when your Solar heating panels are running the SWG is going into a low flow condition and stopping generating chlorine.

Look at when the SWG is shutting down.

Show us pics of your equipment setup.
 
ajw22 said:
Welcome to TFP.

I do not know the Viron SWG system. Does it use a flow switch or other flow sensing mechanism to turn itself off when it has low flow?

I suspect that when your Solar heating panels are running the SWG is going into a low flow condition and stopping generating chlorine.

Look at when the SWG is shutting down.

Show us pics of your equipment setup.
Click to expand...
Photo attached. I believe the solar heater is on a separate line and does not impact flow to the SWG. In any event, I have turned off the heater and have the same result and at present the solar heater does not come on much anyway given it is hot every day here in Perth.
 
Karlosw said:
Photo attached. I believe the solar heater is on a separate line and does not impact flow to the SWG. In any event, I have turned off the heater and have the same result and at present the solar heater does not come on much anyway given it is hot every day here in Perth.
Click to expand...
my SWG chlorinator is essentially this one without that blue tooth control

www.astralpool.com.au

Viron Salt Chlorinator with Bluetooth Control | AstralPool | AstralPool Australia

AstralPool's Viron Saltwater Chlorinator provides you efficiency, control and convenience. Produce the highest level of chlorine with lowest power consumption.
www.astralpool.com.au
 
Starting a slam process. Key test results today for start of process:
CYA 40 (was 70 four days ago), FC 2 (added 6.2 liters of liquid chlorine to boost to 16), pH 7, TA 150, CH 225, salt 6000
 
aussieta said:
do you have recent test results
and history test results
Click to expand...
Unfortunately I have not written down recent results. But FC went something like this over the past week and a half.

Day 1: 20 (end of last slam)
Day 6: 5
Day 7: 4
Day 9: 0
Yesterday (day 9) I added 2.2 liters to get up to 5 and left the chlorinator on full over night. By 2pm today (day 10) was only 2.
 
Last edited:
Karlosw said:
Unfortunately I have written down recent results. But FC went something like this over the past week and a half.

Day 1: 20 (end of last slam)
Day 6: 5
Day 7: 4
Day 9: 0
Yesterday (day 9) I added 2.2 liters to get up to 5 and left the chlorinator on full over night. By 2pm today (day 10) was only 2.
Click to expand...
7.30pm FC at 11ppm. Based on chlorine added at 2pm should have been at 16ppm. So 5ppm drop over 5 hours with chlorinator on max output.
 

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Karlosw said:
7.30pm FC at 11ppm. Based on chlorine added at 2pm should have been at 16ppm. So 5ppm drop over 5 hours with chlorinator on max output.
Click to expand...
Stick with it. FC consistency is key. Be sure to inspect & brush all areas of the pool to include any potential hiding places for algae. Good luck!
 
I know you posted in my thread (I have replied) but your symptoms are uncannily similar to mine.
I've gone through my 2nd SLAM and maintained SLAM levels for 4 days until I was confident OCLT showed < 1ppm loss.

During the SLAM I had my SWG on 0%. I.e. not producing chlorine. I was purely relying on LC additions. It also made the OCLT easy - eliminating SWG as an element.
Once SLAM was over, I set my SWG to 70% for 13 hours & just waited for the chlorine to come down.

Tested 2 days later and I discovered that chlorine still at SLAM levels, so dropped it down further to 50%.
I figure the slower the taper, the better fight against hidden algae/bacteria - even though the water is utterly sparkling & pool is pristine clean.

I'd like to give an answer as to why (the "why" I have given up on) but really the goal is to get back to the SWG levels I am used to.
I will test water again on Saturday and see what FC levels I get. That'll be 6 days since end SLAM.

Keep going with the SLAM.
I assume you're vacuuming, clearing skimmer box of leaves? I.e. removing any foreign bodies which might cause algae?
And scrubbing pool walls, getting into the skimmer box with a nail brush and giving that a thorough scrub too?

When the SLAM is over (i.e. you get OCLT test < 1pmm) then keep SLAM going longer. Get 2 or 3 nights in a row passing the OCLT.

See my thread, but @Ahhsomeguy suggested I chuck some BioKlenz . So i did that in the middle of SLAMming.
So far I don't know if it has made a difference but it certainly hasn't hurt. I suggest you do that too. Read the pack for the qty to add. Not cheap though - I paid $49 for a 1L bottle. Cheaper online.
 
Thanks for the advice. I will check out the Bioklenz too. I haven’t done the scrubbing yet, hard to find time during the week, but will do this weekend. After recent experience I will definitely be maintaining the slam for a few extra days.

By the way, I also have suffered the cya loss. Went from 70 to 40 in a few days. This could have been because I was down to low chlorine levels (I think I read that algae can eat cya if chlorine is gone).

It is a frustrating experience as I had three years of no problems!!
 
Youfah Mizzum: The BioKlenz goes to work immediately on biofilms within the plumbing system and those tiny stickies to the aggregate surfaces that are microscopic. Using this product you will not see instant changes. It takes a week or so to begin to notice subtle changes. You may also find that the sanitizer demand will rise on you as more detritus organics are dislodged into a planktonic state. Remember, as soon as you get most of the biofilms removed it begins to attach anew, especially when the pumps are shut off and there is no water flow. Thank you for keeping the forum notified as to your journey. Pool owners typically have no sense of biofilm formation causing them problems as hot tub and swim spa owners readily see and deal with. Pools can have considerably MORE build-up than the smaller hot water vessels. The Bio-Klenz will aid in it's removal and your water quality and feel will also be greatly enhanced.
 
ajw22 said:
Algae does not eat chlorine, ever.

CYA - Further Reading

www.troublefreepool.com www.troublefreepool.com

Ammonia will eat CYA. But if you have CYA 40 then it was not due to ammonia since ammonia will take CYA to 0.

Ammonia - Further Reading

www.troublefreepool.com www.troublefreepool.com
Click to expand...
Thanks.
My chlorine did got zero for a day I think so the scenario in that article may have occurred:

“There is bacteria that feeds on Cyanuric Acid and will create ammonia in pool water. This can only occur if the Free Chlorine falls to 0 allowing the bacteria to live. This generally happens in pools closed for the winter and discovered at pool opening”

I certainly lost 30ppm of cya over a couple of days. But chlorine was only at zero for one day max.
 
Karlosw said:
Thanks.
My chlorine did got zero for a day I think so the scenario in that article may have occurred:

“There is bacteria that feeds on Cyanuric Acid and will create ammonia in pool water. This can only occur if the Free Chlorine falls to 0 allowing the bacteria to live. This generally happens in pools closed for the winter and discovered at pool opening”

I certainly lost 30ppm of cya over a couple of days. But chlorine was only at zero for one day max.
Click to expand...
If you got hit with ammonia your CYA would go to 0 and you would not be able to simply add CYA to up it without a process first of clearing the bacteria with a lot of chlorine. That was not the behavior you described.
 

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