Using flocculants while the sand filter is filtering

[amin36]

Hi guys

First of all i know that TFP does not recommend using flocculants so this is only my personal question and i mean no offense

While doing the maintenance of one of my client's pool,i gave her PAC (poly aluminum chloride) for flocculation and after adding it to the water she forgot to change the multi port valve of the sand filter from filter to recirculate.

And as far as i know when something like this happens the filter must be clogged up and one should change the filter media .
I should mention that the water changed to crystal clear
While doing the maintenance of one of my client's pool,i gave her PAC (poly aluminum chloride) for flocculation and after adding it to the water she forgot to change the multi port valve of the sand filter from filter to recirculate.

And as far as i know when something like this happens the filter must be clogged up and one should change the filter media .
I should mention that the water changed to crystal clear afterward

Anyways i decided to open the filter and surprisingly watched that there was no clogging at all and filter media was quite fine.

I am wondering whether we can use flocculants as clarifiers with no damage to sand filter media.

What is your opinion?

 

[JoyfulNoise]

Flocculants are meant to be removed by vacuuming to waste. You add them to the pool and then only recirculate long enough to distribute the chemical (usually an hour or two). Then you shut off the circulation and let the floc fall to the bottom of the pool (typically 24 hours later). You then vacuum the floc to waste to remove it.

If you leave a filter in filter-mode, some of the floc'd particulates will make their way into the filter and get trapped. Floc's do not last forever, they begin to break down back into their smaller particle sizes within a few days (there's an entire technical discussion of why and how this happens that is not necessary to get into here). So, any fine particles trapped in the filter as floc will eventually start to break up again and then come out of the filter. It won't be terribly obvious but what you will see is cloudy water developing slowly over time.

Your best option right now is to shutdown the pool filter and do a deep clean of the sand filter to remove and floc that might be trapped in it. Then see if anything drops out of solution in the pool that you can vacuum from the bottom. All vacuuming should be done to waste, not through the filter media.

This is the reason why TFP does not recommend floc's to the general user. As you can see, a person can easily screw it up and leave themselves with a bigger mess to deal with.

 

[Charlie Bezzina]

Hi. The pool balancing and handover 'professional' who handed over my new pool put a flocculant in my pool and proceeded to vacuum directly into the filter media. I watched him do it. The water looked nice when he packed up for the day... Needless to say it all came back out the returns after a few days. I was not tfp educated at that time.

I have more stories about this 'professional' if anyone needs a chuckle.

 

[amin36]

@Charles Bezzin May be he should have backwashed the filter after vaccuming the floc into the filter.there would have been no problem if he had done it​

 

[amin36]

@JoyfulNoise Here something that i guess is that it might depend on the rate of sand filteration.probably if one uses a slower-rate sand filtration (i mean the maximum rate to be no more than 12 GPM/ft2)the floc will remain in the filter and would not break and get back in the water and one can get rid of it through backwashing of the sand filter.​

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any opinion?​