Lay My Hat

Naive question. Will it work if I don't run the chlorine down but adjust the levels back up again after treatment?

Apologies for the TC, but which titration testing kit would you recommend please Teapot? There seem to be so many different ones it's a bit bewildering (like most things for me, really).

Casscat wrote:Naive question. Will it work if I don't run the chlorine down but adjust the levels back up again after treatment?

Not naive, many pool shops and builders don't know what to do.
What will happen is you will use more ascorbic acid which will cause the chlorine to drop rapidly burning out the ascorbic but also that extra ascorbic used will cause a bigger chlorine demand to get the chlorine level back up again. One chap last year didn't allow the chlorine level to drop from the shocking he gave the pool, took him around 10 days to get the chlorine to hold but I gather he used about 5 kilo's which is just mad.

Just go easy with it, if you can get some de chlorinator (sodium thiosulphate) that would work but what level is the chlorine if it only 1ppm then you should be ok with the ascorbic.

jlaceysmith wrote:Apologies for the TC, but which titration testing kit would you recommend please Teapot? There seem to be so many different ones it's a bit bewildering (like most things for me, really).

What are you looking to measure?

Sorry, Teapot. The usual daily/weekly tests. We've used strips in the past and we haven't had a problem, but think we should use a better method.

teapot wrote:

Casscat wrote:Naive question. Will it work if I don't run the chlorine down but adjust the levels back up again after treatment?

Not naive, many pool shops and builders don't know what to do.
What will happen is you will use more ascorbic acid which will cause the chlorine to drop rapidly burning out the ascorbic but also that extra ascorbic used will cause a bigger chlorine demand to get the chlorine level back up again. One chap last year didn't allow the chlorine level to drop from the shocking he gave the pool, took him around 10 days to get the chlorine to hold but I gather he used about 5 kilo's which is just mad.

Just go easy with it, if you can get some de chlorinator (sodium thiosulphate) that would work but what level is the chlorine if it only 1ppm then you should be ok with the ascorbic.

If the ascorbic is being applied topically then does the chlorine level matter? The amount being used is not huge and the sock technique targets the area to be treated. Can I just try the application and then reset the pool levels afterwards? Obviously I don't want it to take ten days to recover as I will be having guests arrive two days later! Too risky?

jlaceysmith wrote:Sorry, Teapot. The usual daily/weekly tests. We've used strips in the past and we haven't had a problem, but think we should use a better method.

Now with the greatest of respect, without another tester to check against you are not likely to know The strips oblige by changing colour but where that is in relation to the actual reading is the funny bit.

I am and have been beating the suppliers verbally for a couple of weeks to get the best prices for test equipment, if you can bare with me for a day or two I have one more to get in contact with.

Casscat wrote:
If the ascorbic is being applied topically then does the chlorine level matter? The amount being used is not huge and the sock technique targets the area to be treated. Can I just try the application and then reset the pool levels afterwards? Obviously I don't want it to take ten days to recover as I will be having guests arrive two days later! Too risky?

Yes it should be ok, let me explain a little what's going on. The iron has several different forms some are in solution and they can change form and stain. The ascorbic acid is a reducing agent and and changes the form back to a non staining in solution form. If the chlorine level or pH is too high it will re oxidise and stain. Once the stain is removed and the iron is in solution the sequestrant is added and this binds to the iron to prevent it changing form again (at least for a while)

On the pool picture I showed earlier, I removed the iron from the pool, not sequestered it so no problem is likely to re occur providing the owner changes out the iron screws for 316 stainless steel which was the cause in his case.

Thank you Teapot, that's kind. Sorry to interrupt your thread, Casscat - I hope you can sort your pool out soon!

Just popping back into this one briefly. The ascorbic minimised the staining very temporarily but the effect wasn't worth the impact on the pool chemical balance. We are edging towards Decision Time in terms of getting proper remedial work done, and my manager has been speaking to a pool firm locally who are suggesting that instead of excavating all the concrete they can simply strip off the tiles, lay a special resin bonding and then retile and this will keep the rust at bay. What say you Teapot? Is there such a system which will create an impermeable barrier long term? Seems kind of logical to me but what do I know.

Now that description isn't how I would carry out such a repair, that sounds more like a quick bodge. To be sure I asked the same question of a friend who also caries out repairs of this type and we both agreed that the rusting material needs cutting back with a diamond disk'd angle grinder and then the area re filled with epoxy mortar.

I would also put the new tiles on with epoxy tile adhesive (for pools) and epoxy grout to give maximum water protection compared to cement based adhesive and grout.

Would the cutting back actually involve digging up the whole pool though as although there is only one area of rust at present it's a pretty fair bet that the same deterioration is present all over. It's a massive project for a 10m x 5m pool

It shouldn't mean a total removal, should just be a local repair. the re enforcement is in panels normally so if one part is high the rest should be lower so a small area only I would hope.

I will inspect when I get out there in September, but manager says that more rust spots are appearing.

Trying to keep positive if you have one rust area, the iron staining will migrate all over not necessarily meaning the rebar is coming through in all areas.

Well that's fingers crossed for you.