Request help raising chlorine levels after Ascorbic Acid treatment

[KazooTom]

Split from Ascorbic Treatment--gone bad?? Zea3

Ascorbic acid and chlorine destroy each other. It is normal to have trouble raising the FC level after an AA treatment. Just keep adding small amounts of chlorine and it will eventually hold. You don't want to add too much chlorine all at once because that can cause the metal stains to reappear.

I really would like a few more specifics on the use of liquid chlorine to return the pool to "balanced" after using ascorbic acid to remove iron stains. Don't want to do something by mistake and end up with the "iron" precipatating out. My pool looks great without the stains -- really want to keep it that way.

What does it mean to add the chlorine SLOWLY? (e.g. 2 cups or 1qt at a time or a half gallon?) How much is A LOT of chlorine that is usually needed to get the job done. (2gal/4gal/6gal of 10%) What is the earliest I may find the FC holding . . . How likely is it to take a week or more to hold the FC? Will continue to add Polyquat 60% every three days until FC holds.

Here's my situation. I have a 12000gal in ground pool with vinyl liner. Used 1lb ascorbic acid and stains completely disappeared. Added amt. of sequesterant treatment on bottle plus 25% more and have run it first on recirculate and now 24hrs later on filter. PH 7.1, TA 100, FC 0.0. Pool calculator says 23oz to go from 0.0 to 1.5ppm FC. How should I proceed to add liquid chlorine (10%)? How often should I test for FC? Should I keep adding and testing every 30mins until I get to 1.5ppm -- and use that amount to keep FC up. Lot's of specific details about using "ascorbic acid" -- more vague in the on-line directions about "how" to safely get back to operation. Appreciate any concrete advice you can offer. I know that size of pool, organic debris, water temp. can factor in. Just would like some better idea of what is a prudent way to go.

 

[UN1017]

It's hard to say because you have to take organics and the AA into account. If my math is right, 4 oz. of AA neutralizes 1 ppm of FC in 12000 gallons. That means if you only take the AA into account, you need 4 ppm of FC to eliminate the AA. In your pool, 4 ppm FC is 60 oz of 10% bleach.

I would add that amount over several hours and just make sure your sequestrant levels and pH are kept in check. I would continue gradual (15 oz) additions over hours (maybe a couple days) until it starts to hold.

 

[KazooTom]

Hey 1017: Thx for the prompt reply. Your advice helps me to get started.

The end goal for FC level that holds then is 4ppm?

FYI my CYA level is 45-50 and the Best Guess Chart comes up with 4-6ppm FC too for that level of CYA.

When should I begin to get a FC reading above "zero"with my TTK drop test (DPW) even if it disappears again in a short time-- maybe after adding the 60oz gradually?

 

[duraleigh]

The end goal for FC level that holds then is 4ppm?

FYI my CYA level is 45-50 and the Best Guess Chart comes up with 4-6ppm FC too for that level of CYA.

No, your goal is to restore your pool to the values suggested in the FC/CYA chart. It happens that 4 ppm will work but you seem to say that there is a different set of levels for pools having completed AA treatments.....there is not. Resume your daily FC additions and testing in that 4-6 ppm range and you should be fine.

When should I begin to get a FC reading above "zero"with my TTK drop test (DPW) even if it disappears again in a short time-- maybe after adding the 60oz gradually?

Maybe is the correct answer. No one can calculate that but you will be able to see it by testing correctly.

 

[KazooTom]

Most advice on-line says to keep FC chlorine levels at 2ppm or under for 1wk or 2wks after adding the ascorbic acid. I guess I was confused and thought that 4ppm instead of 2ppm was the better initial hold point. Glad that you asked me to reread. Thx.

Showing a 1ppm FC reading right now with the Taylor DPD drop test. Will keep checking every few hours. PH around 7.1 to 7.2. Will test a few times today. If FC drops will keep adding liquid (10%) at 2 cups every few hours. Wish me success.

 

[singingpond]

KazooTom, you may want to PM user swampwoman and ask her to look in on this thread - she has personal experience with metal sequestrants and AA treatments, and her comments are always well informed and thorough.

 

[Swampwoman]

Good morning, KzooTom! Sorry I missed this...busy with guests

Btw, Singinpond, thanks for the vote of confidence, but I should disclose that I completely avoid AA treatments these days due to the precise anxieties expressed by KazooTom

So, Tom, here's my 2 cents, but your mileage may vary...the reason for the advice to "slowly" bring up the FC is to avoid the incidence of albeit temporary high ph or shock/slam value.

So, in other words, if your dosing and dosing and dosing because the excess AA is giggling up the chlorine you add, it would be easy to overshoot once the AA s gone and raise the FC tooooo high! (Thereby oxidizing the iron again and possibly neutralizing the sequestrant, which also advises against "shocking" for a week.

At the same time, at least half the folks I read seem to end up with algae from riding FC too low after an AA treatment. Quite a Sophie's choice to my mind!

So what I did and somehow managed to avoid either extreme was this (and I should note the polyquat also seems to fight chlorine a little in my experience):

After letting the sequestrant have a day post-AA, I would (for my specs...note I never zeroed out) add a half gallon 12% (about 2.5 pm) with filter running. In an hour, I'd check again, check my ph, and add another half gallon. I would basically do this all day, usually on a Sunday, until FC was holding at the lower end of my range (in my case, 3 ppm) for the first day. The next day I'd dose up to the higher end of my range, so that by day 2 I wasn't dropping below my low end/min. Number.

In other words, I'd simply devote a day to careful checking and frequent but "gentle" dosing until the FC was holding - watching the ph as well. Depending on how much AA I had used, this might take four gallons of chlorine.

Since you've gone to zero, in your shoes I'd add 4 ppm right away, then check back in an hour and "gently" titrate up until you've exhausted the excess AA.

Hope that helps, as imprecise as it is in terms of advice

The second secual thing for me to share might be what I now do instead of AA, which again -- your mileage may vary

Instead of doing AA at all, I read a thread last year where a member named RavenJim did the Metal Magic sponge test, used a mega dose of Metal Metl magic for the staining, and then simply maintained the MM. What I liked about this method was tat MM want your ph to e above 7.5 when you initially treat with it...so the bons is I don't ave to tinker with MA

I will go look up the link fr directions on the test.

Metal Magic is produced by proteam, which is Haviland here in GR. so they're your neighbors I order men nlne from Pool Chemicals, Hot Tub Chemicals and Supplies | Pool Geek for best price and overnight shipping ... They're in MI too on the east side.

The othe thing I like about MM is their techs are great and are happy to chat with you if you just give them a call.

With all that said, I don't know the history of your water/well/ppm Ron etc. but will say the est thing ve done to keep things manageable is to plumb te outdoor spigot and upgraded my water softener to dual tank for to ups. Salt never gets ALL the iron, so you'll still get trac amounts tat add up over time, but the load is really reduced.

Lastly, in Kzoo, you have a fellow at a co. called The Water Boys who can fill you up if you want to start clean and only use te well fr top up.

The thread about using only MM:
Switching Sequestrate from EDTA to HEDP

Metal magic sponge test: http://www.proteampoolcare.com/images/uploads/MetalMagicSpongeTest.pdf

 

[KazooTom]

Hi Swampwoman:

Thanks for sharing. It's Sunday so I'm following your hourly procedure so hopefully I can get it to hold. Another sunny day and I seem to be losing 1ppm per 1-2 hrs. Adding about 1qt at a time -- about every 2hrs or so. Would like it to hold at 2-3 ppm for several daylight hrs -- perhaps hold overnight? Both DPD drop test and strips are now showing about the same readings today.

I can see why you are enthused about MM -- another time I may give it a try myself.

Portage City water is well water -- become more rusty in past few years as they've gone deeper and deeper. Been using a hose end filter and now Curalator to capture rust. Many feel that filters alone or with some DE help can't capture or backwash rust debris. Products like MM and other sequestration make the opposite claim. Wish someone would do the research to give us some concrete info.

I give you credit for bringing back your pool from the swamp. They do take a lot of care. Had to change the sand media, remove a chlorine lockup, refill 2/3 to lower CYA, kill algae and a bit of pink slime, and now the AA issue. Enough already. In about 3wks the season is over. Not a good summer pool wise for me.

Thanks again for your thoughts. Nice to have a neighbor in GR to talk things over with. Dealing with one pool problem is tough enough -- a summer of them makes you think about filling it in. Thank heavens for college chemistry.

 

[pabeader]

One thing to remember, once you get it over this hump and it's all sparkly and shiny, it should be a dream to take care of. After you open next year just keep the FC at or slightly above recommended for your CYA and you'll be clean and sparkly all next season.

Remember to follow the closing suggestions in Pool School. This will be my first winter with a pool so I haven't decided if I'm going to close or just go dormant.

 

[KazooTom]

Good News! Followed the advice of both UN1017 (amounts of liquid chlorine) and Swampwoman (for her general procedure) and my chlorine levels stabilized after about 5-days of gentle treatment. Took around 3.5 gal. of 10% pool sanitizer -- perhaps a bit more to get things to hold with my 12K gal. pool using 1lb of AA. Many thanks to both of you. Had good luck with a highly concentrated sequestrant (Stain-X) which managed to suspend the iron after it had begun to reappear as light wall stains. Wish I had started with that N Jonas & Co. highly-concentrated product to begin with. The ascorbic acid did drop my TA significantly. Took about 8lbs of baking soda to bring it back to 100+ -- recommended level for vinyl liners. The pool looks the best it has in years. While I would do it again, if necessary, this was not so easy to do. You really need patience and attention to details. Use the least amount of Ascorbic Acid you need to get the stains removed. Go with a really concentrated sequestrant. Consider using a hose-end filter when putting new water in along with the CuLator Metal Remover --widely available -- to collect suspended iron and other metals. Several people recommended both as followup protection and a way to getting the metals out of the pool for good. Vacuuming/backwashing according to many doesn't do it. Really appreciate all your help. My pool looks the best its looked in years -- totally stain free. Hope I won't have to do it again very soon. I guess time will tell.

 

[pabeader]

So glad to know that you were able to get things looking great!

I would note one thing in what you last wrote. You said you brought your TA up to 100. Is that where you would normally keep it? TA from all my reading here, is the one thing you really need to let find it's own happy place. It is VERY pool dependent. The reason for this is that is drives/buffers pH. If the TA is too high then the pH will rise. Too low and pH can wander, bouncing all around. What I have read is that once everything else is under control, you watch your pH. If it starts to rise use muriatic acid to lower it. This will naturally lower TA. Don't correct the TA. Watch your pH. Most folks have issues with pH rising so you would continue to lower with MA as needed until it stabilizes. I've seen TA readings of 40 and 50 be good for some folks, whereas 75 to 100 will be good for others.
Remember PoolMath is your greatest asset.

I also, note that in your sig you mention 'chlorine lock'. From what you have learned here; I'm sure you now know there is no such thing. You might want to update your sig to reflect new found knowledge.

 

[UN1017]

I'm glad it worked for you. Keeping metals out of your pool may prove to challenge because of your water source. It seems you have already addressed those concerns. As pabeader said, don't obsess over TA. Let it find its happy place. The best advice I can give is to watch your pH like a hawk. Keep it down at 7.5 at all times, which may mean your TA may need to be brought down to offer some stability.

Also, is bleach your normal method of chlorination? or are you using a tablet feeder as well?