Foam layer on pool?!?

[HarrisonHRG]

evening,

Discovered for the last 48hrs we have a horrible looking light foamy layer on our pool surface.

all tests complete with a Palintest6

FC: 3.8
CC: 0.3
CYA: 14 (indoor pool so chlorine moderator only)
CaH: 360 (a little high, maybe need to stop using CAL HYPO during SLAM)
TA: 110
PH: 7.2 (maintained by SWG system)

This scummy layer doesn’t seem to move or be filtered out by the glass media filter and it has been present for a few days.

Any pointers to remove this id appreciate?

Here’s some pictures. Only completed the SLAM process 5 days ago!

 

[PoolStored]

What chemicals have you added in the last 7 days?

 

[HarrisonHRG]

What chemicals have you added in the last 7 days?

Only Cal Hypo (whilst doing a SLAM)

Hydrochloric acid is auto dosed. Nothing else.

 

[mknauss]

If you used cal hypo for a SLAM, you used a lot. Any non reactive particulates in the product likely are creating what you are seeing. Try a small amount of Dawn dishwashing detergent (or equivalent that you would have) to see if that breaks the surface tension and allows the particulates to be filtered out.

 

[HarrisonHRG]

If you used cal hypo for a SLAM, you used a lot. Any non reactive particulates in the product likely are creating what you are seeing. Try a small amount of Dawn dishwashing detergent (or equivalent that you would have) to see if that breaks the surface tension and allows the particulates to be filtered out.

Used about 1.6kg in total...

I was thinking about a drop of dish soap (we call it Fairy Liquid in the UK) - Wouldnt this cause a bubbling effect at all?

Some things online mention "Enzymes" - Any ideas what that is? the same thing?

 

[mknauss]

You could try Enzymes. Key is to get it without a bunch of additives. Not sure what you have available.

A few drops of Fairy Liquid will not foam up.

Hard to believe you could do a full SLAM process using 1.6 kg of cal hypo in 77 cubic meters of water.

 

[HarrisonHRG]

You could try Enzymes. Key is to get it without a bunch of additives. Not sure what you have available.

A few drops of Fairy Liquid will not foam up.

Hard to believe you could do a full SLAM process using 1.6 kg of cal hypo in 77 cubic meters of water.

My cal Hypo is 72%

My starting chlorine level (thanks SWG) was 9.2, so the 3 days it took to meet the criteria wasn't too bad on the Cal Hypo.

I will give a few drops of fairy liquid a go and see if it coagulates the foam.

Thanks for the advice will feedback

 

[AUSpool]

I’ve seen similar when adding salt. I use my scoop/net until it’s all either in the net or dissolved and then rinse the net with my hose.

I would switch to regular liquid pool chlorine for a slam next time. It sounds like you’re slamming quite regularly, I have never needed to slam in 15 years, it shouldn’t be a regular maintenance thing.

Your pH is quite low, there is no need to force it down to 7.2, 7.6 is fine.

I would aim to keep your CyA between 20 and 30ppm.

 

[HarrisonHRG]

I’ve seen similar when adding salt. I use my scoop/net until it’s all either in the net or dissolved and then rinse the net with my hose.

I would switch to regular liquid pool chlorine for a slam next time. It sounds like you’re slamming quite regularly, I have never needed to slam in 15 years, it shouldn’t be a regular maintenance thing.

Your pH is quite low, there is no need to force it down to 7.2, 7.6 is fine.

I would aim to keep your CyA between 20 and 30ppm.

Interesting, we did add some salt now thinking of it a few weeks ago, could be that indeed.

Liquid chlorine for slam is definitely on the list after this Cal Hypo is used up.

reason for the shock (needs it after heavy use or around once every 3 months) and the lower CYA is it’s an indoor pool with extremely high bather load. (Had 400 people in it over 7 days before!)

UK regs state there should be 0 CYA in a indoor pool, so I’m running a little CYA solely for its chlorine moderation on the bather to reduce HOCL harshness..

I hope that all makes sense and doesnt sound too daft .

Interestingly my SWG states PH should be “maintained between 7-7.4” - always kept it this way?

 

[AUSpool]

Interesting, we did add some salt now thinking of it a few weeks ago, could be that indeed.

When I notice it with salt additions it’s almost immediate, caused by the small amount of impurities in the salt (~0.6%). Our regular salt is really quite good but it doesn’t take much. I suspect your foaming is caused and interaction between impurities in the calhypo and oils, lotions, ect. introduced by the high bather load. Manual dispersion with a net and a drop or two of dish detergent as mentioned should clear it.

reason for the shock (needs it after heavy use or around once every 3 months) and the lower CYA is it’s an indoor pool with extremely high bather load. (Had 400 people in it over 7 days before!)

That makes sense. Liquid chlorine would be a better option and prevent the foaming.

UK regs state there should be 0 CYA in a indoor pool, so I’m running a little CYA solely for its chlorine moderation on the bather to reduce HOCL harshness..

Not surprised. The only reason I mentioned it was for confidence in the test result. The closer you get to zero the less confidence you have in the result. I would just try to stay near 20ppm. It has a very good affect on chlorine moderation or stabilisation, even at low levels. I even read the term “chlorine sequestering tendency” just recently although its more of an equilibrium reaction in reality.

Interestingly my SWG states PH should be “maintained between 7-7.4” - always kept it this way?

I bet they don’t say why. Normally it’s old habits. The equilibrium of HOCl and OCl- is ~7.5 where the concentration of HOCl is greater below 7.5, its normally related to that. But there is still plenty of sanitising FC at 7.8 so it shouldn’t matter. And with CyA, even a small amount the dependency on pH is greatly reduced. There is no difference to bather comfort particularly to eye comfort.

Start by trying a ne target of 7.4-7.5, you’ll use less acid and bicarb.

 

[HarrisonHRG]

When I notice it with salt additions it’s almost immediate, caused by the small amount of impurities in the salt (~0.6%). Our regular salt is really quite good but it doesn’t take much. I suspect your foaming is caused and interaction between impurities in the calhypo and oils, lotions, ect. introduced by the high bather load. Manual dispersion with a net and a drop or two of dish detergent as mentioned should clear it.

Ah yeah that makes sense, now thinking about it we used a paint mixer in buckets to pre dissolve the salt, so maybe thats caused our issue? - it did have a slightly foamy layer after doing that too!

That makes sense. Liquid chlorine would be a better option and prevent the foaming.

We never had any issues with our cal hypo before in terms of foaming (when i first took over the chemical management pool was green and full of algae but no foam from the same shock) - but agree, thatll be the last of our shock and liquid chlorine is what we will be going towards.

Not surprised. The only reason I mentioned it was for confidence in the test result. The closer you get to zero the less confidence you have in the result. I would just try to stay near 20ppm. It has a very good affect on chlorine moderation or stabilisation, even at low levels. I even read the term “chlorine sequestering tendency” just recently although its more of an equilibrium reaction in reality.

Interesting - our test kit says it accurately measures down to 3ppm with a +- 1 ppm variance. Im consious given our bather load to keep the CYA on the lower end of recommended, so far seems to work a dream.

bet they don’t say why. Normally it’s old habits. The equilibrium of HOCl and OCl- is ~7.5 where the concentration of HOCl is greater below 7.5, its normally related to that. But there is still plenty of sanitising FC at 7.8 so it shouldn’t matter. And with CyA, even a small amount the dependency on pH is greatly reduced. There is no difference to bather comfort particularly to eye comfort.

Start by trying a ne target of 7.4-7.5, you’ll use less acid and bicarb.

I've put it to 7.4, lets see ! thanks for the information on that. we are currently using a ORP sensor for it, so adjusting the PH will change that setpoint so ill look forward to changing that around soon lol.


Dish soap and use the net is the way i think to try and shift it, and in the future just dump the salt in and let it disperse itself??

 

[AUSpool]

I've put it to 7.4, lets see ! thanks for the information on that. we are currently using a ORP sensor for it, so adjusting the PH will change that setpoint so ill look forward to changing that around soon lol.

If your comfortable with how your managing CyA between 10 & 15ppm stay with that. ORP probes are sensitive to CyA.

 

[AUSpool]

Dish soap and use the net is the way i think to try and shift it, and in the future just dump the salt in and let it disperse itself??

Don’t leave salt sitting on the bottom, it can stain. Use your brush to push it around until its dissolved.