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mary jo
08-06-2014, 08:19 PM
Hello! I ama fairly new pool owner (July 2012) and have a pool waiter problem that no one so far has a solution to!
Stumbled across this website while researching pool chemistry. Hoping you can help!
POOL STATS: (I tried to edit my profile but said I didn't have permission until I posted?)
15,000 SF rectangular, in-ground w/ vinyl liner
Pentair ¾ HP self-priming pump
Pentair Clean & Clear Plus Cartridge Filter. Model# CCP240.
Nature2 Mineral Sanitizer: Professional G Vessel
In-line chlorinator
Heater (gas)
Automatic Pool Cover

I keep the pool warm (80-86 this season).
I close the pool (automatic pool over) nightly, open again by 9-10am.

Chlorine Supplies: 3” tablets (GLB or Doheny’s brand):
Trichloro-s-Triazinetrione: 99%, Inert Ingredients: 1%, Available Chlorine: 90%
Superchlorinator (to shock the pool): GLB Super Charge: 68% Calcium Hypochlorite

My problem began about 4 weeks ago. I noticed that Chlorine levels (FC and TC) were steadily dropping- from 1 to .5 to zero. I normally keep FC level at 1-2 was told I didn't need to go higher since I nada mineral sanitzer and CL demand would be low.
WHen TC and FC both reached zero for several days I texted my pool guy (pool installer) and he recommend getting water tested by pool store (The Great Escape) and shocking the pool with 2 lbs shock powder.

Water testing yielded strange results: FC=0. TC=0 pH=6.5 TA=24 CYA=115, hardness =199 no metals present, HIGH phosphates present )the exact number was not given in the report).
My test rests showed FC=0 TC=.5 pH=7.2 TA=110 (I didn't have tests for other criteria)

They recommended: shock w/ 2 lbs "Natures' Way Super shock, add 22 lbs alkalinity plus, add 1 1/2 lbs pH up, add 1.5 Liters commercial strength Phos free.

I started with shock: last Friday I shocked my pool with 2 lbs Lithium based shock (they said it was the most popular type and wouldn't stain my vinyl liner. Zero chlorine reading the next morning.
Saturday evening I tried chlorine based "super shock". Zero Chlorine reading the next morning.
I didn't believe their pH and TA reading were correct so I added only phos-free on Sunday. Within an hour the filter pressure soared from 15 to 28 and water circulation slowed dramatically, and the water clouded. The next morning I barely had enough suction to vacuum up the white residue on the bottom of the pool. The pool water was once again crystal clear.

I remember my pool guy telling me that sometimes fertilizer could mess up pool chemistry and incidentally I had my lawn treated at the same time my FC levels started dropping. He suggested the pool might be over chlorinated and bleaching the free chlorine results and suggested I shock the pool again, test again for phosphates. He's not sure why shocking the pool is not raising my FC level. ARGH!!!

It's now Wednesday evening and even with reduced water flow, gunked up filters and zero FC in the water for several weeks now, the pool looks great.

Well, I am still waiting for my new filter cartridges to come in- i want my pool guy to install them only so that I can learn how to do them myself next time. (I'll admit the warning in the filter manual intimidates me…"These instructions MUST BE FOLLOWED EXACTLY to prevent the lid from blowing off during system restart or later operations"…)
Here's the latest water testing results that I took today:
FC=0
TC=0
TA=130
Hardness=750
pH=7.2
phosphates=500-1000 (did this test 3 times- dark blue but difficult to discern which color exactly)
CYA=way over 100 (the test vial (Taylor) only went up to 100, but the cloudy liquid measured 1 1/2 cm tall in the vial if that means anything.

Hopefully I'll have new cartridges tomorrow, BUt after reading about the CYA and Chlorine connection I think I understand that the amount of shock rehired to unlock the combined chlorine level needs to be much much much higher that the 2 1/2 + 2 lbs of shock that I added last week. SO why hasn't any pool guys or pool store guys mentioned this fact to me????
The kids are so bummed - they see a beautiful clear pool and don't understand how it can be so d dirty they can't swim in it….HELP!

BigDave
08-07-2014, 10:27 AM
Pick up a cheap OTO / pH test kit. The OTO (yellow drops) it is reliable well outside normal range and will tell you if chlorine is high or low.
Do you have a K-2006?
Dilute a pool water sample 1:1 with tap water and measure CYA of diluted sample(then multiply by 2). If it's still over 100 (200) then dilute a pool water sample 1:2 with tap water and measure CYA of diluted sample(then multiply by 3).

mary jo
08-07-2014, 12:18 PM
Good Morning. I have only ever used Taylor drop testing kits. Currently I have: K2006, K1004 (residential trouble shooter) and K1106 (phosphate). This morning I tested again: FC=0, Ph-7.2, TA=130. I ran the CYA test 3 times and took an average: 150.
My new filters have bee installed.

BigDave
08-07-2014, 02:14 PM
I suggested the OTO kit because OTO will not bleach out in high chlorine.

How did youn test CYA 150ppm?

Congrats on the new filters.

Watermom
08-07-2014, 03:30 PM
And, thank you for the subscription! :)

mary jo
08-07-2014, 03:35 PM
OK- I will try to get the OTO kit, but I did try diluting the pool water with bottled water (all I had) and testing using at different concentrations: 1:2, 1:4 1:9 and got zero chlorine reading all times. I got the CYA reading by diluting my pool water with tap water as you recommended: 1 part pool water, 2 parts tap and got around 50 so I tripled it to get 150.

mary jo
08-07-2014, 04:40 PM
The Walmart/Target stores in my area are all out of hth OTO chlorine testing kits (it's a short swim season here in Illinois). But I did read something in Taylor's manual about how to test for high levels: they suggested adding the 5 drops each of Reagent #1 and #2 into the vial and THEN adding pool water a drop at a time to see if there is any CL is present, so I tried this and the sample never turned pink.

Watermom
08-07-2014, 07:32 PM
If you can't find an OTO kit at Walmart or Target, you can get one at your pool store but just do not let them talk you into buying anything else. They will try!

mary jo
08-07-2014, 08:27 PM
Thank you Watermom!!! I think the problem is: the new post section does not show up at this time ( although it did earlier today).
Anyway- I did find some OTO from a neighbor who had 2- and tested for chlorine and got zero again. Just to see that the OTO was indeed fresh and working I added a drop,of bleach to some water and tested it and it came out dark orange. So I think we an say that my pool has zero chlorine in it, however LOTS of CYA.

FormerBromineUser
08-07-2014, 09:32 PM
Hey, Maryjo.

I am not going to make any chemical recommendations because I am new to the BBB method myself and there are MANY experts here who can help you. (I know what I would do with your test results but...... hint: it starts with b l e a and doesn't include t r i c h l )

I live in Saint Charles, IL so I know what's available in our area. If you HAVE to purchase any chemicals from a pool store, I recommend you go to In-The-Swim. Their corporate offices are in West Chicago and they have an outlet store right there. (They also carry Taylor reagents in case you need them right away). I would not suggest returning to The Great Escape. If you are in doubt, remember that they recommended Alkalinity Plus when your TA is fine.

Get some FC in that pool, and good luck!

mary jo
08-07-2014, 10:15 PM
Thanks FormerBromineUser! I've now read enough posts that I think I should invest in a lot of bleach! I would go ahead and add some tonight just to see what would happen but I'm not sure about how long I'd have to wait until I could close the automatic cover.- which I do every night. I hope this issue gets resolved by next Tuesday- my daughter has planned one last pool party for the season. Fingers crossed!

FormerBromineUser
08-07-2014, 10:39 PM
Yup! No tabs, and lots (and lots) of bleach to bring your FC to >10% of that high CYA.

I have an auto-cover too, and if I have to add more than a quart of 12.5%, I usually wait 1 hour before I close the cover. The bleach just needs to circulate and dilute. So if you're still awake tonight, GO FOR IT!

I am not 100% positive on the following because your CYA is so high, but the auto-cover MAY be your pal in this situation. The auto-cover normally needs to be open only a minimum of 1-2 hours a day to get UV benefits. Keeping it closed more during the day will help you retain some of your chlorine. (Hope the experts chime in here if high CYA is a special situation....)

When you have time on your hands, I also suggest you read about the Nature 2 system and the "minerals" it adds to your water. Just a thought.

BigDave
08-08-2014, 09:38 AM
Thanks for demonstrating that you don't have really high chlorine.

Here's what I think is going on in your pool:
Use of trichlor for primary sanitization has built a very high CYA level (you already know this).
You have kept chlorine level low compared to CYA as recommend by the "mineral system" vendor.
The metal ions (copper and silver, I bet) have helped keep the water clear as the active chlorine level (ratio of chlorine to CYA - not measured chlorine level) fell.
The chlorine / CYA ratio has gotten to the point where there's not enough active chlorine to keep the pool clean despite the presence of metal ions.
Algae (not yet visible) is starting to grow creating the chlorine demand you are experiencing.
The powdered chlorine products you've applied haven't reached a chlorine level effective to kill off the nascent algae.

The simple recommendation is to shock the pool to 30ppm FC but there's a catch. The metal that I believe is in solution in your pool may stain the pool when chlorine is raised. You can test this with a clean, white, 5 gallon bucket. Fill it with about 4 gallons of pool water and add a tablespoon of bleach. Give it a stir and wait a day or so to see if it stains. If it does stain and you want to avoid stains in the pool, post the bucket result here and we'll work out a plan.

If there's no stain or you don't care about staining the pool, you'll need about 10 jubs of 8.25% bleach to get to the 30ppm FC shock level and then you'll need to keep it there until you lose less than 1 ppm FC overnight, you have 0 or nearly 0 CC and the pool is clear. Run the pump 24x7 while shocking. Leave the pool cover open if you can - some of the byproducts produced while shoking the pool may damage the cover.

Phosphate remover is expected to cloud the pool - clean the filter. I'm a little concerned about a hardness reading of 750. Are you sure this test was done correctly?

mary jo
08-08-2014, 11:29 AM
Hi Big Dave- THANK YOU for an explanation that makes sense. The only caveat is that ( and I'm being honest here) I forgot about the mineral sanitizer until I looked through my pool papers, so I have not ever changed the cartridge in 2 1/2 seasons of use. So I wonder if it's still doing anything.

Staining wouldn't be good, but I wondered if I could do a stain test while adding the bleach at intervals. I'm assuming you don't add 6 jugs at once?
Oh- last night at around 10:00 I went ahead and did add 1 jug of bleach, very very slowly to see what would happen. 2 hours later I tested the water, then closed the cover.

Last nights results (around midnight): FC=3.5. CC=1.0
This morning I opens the pool around 10:00 and tested again: FC=1.0. CC=.5

I will start my test bucket, and wait for more info on how much bleach to add.
Thank you !!!

BigDave
08-08-2014, 11:47 AM
I'm glad to hear that the "mineral" cartridge hasn't been replaced - those things kinda make me angry because they're sold on false promises.

Do the bucket test and let us know what you find in it.

Do be sure to keep chlorine in the pool - it will be much harder to clean up a full fledged algae bloom.

mary jo
08-09-2014, 10:57 AM
Good Morning! I just checked the bucket of test water and the bucket is white- no staining at all. I added 1 jug of bleach to my pool yesterday morning, and 1 last evening and this morning the FC=0, CC=1, pH=7.2
What do you suggest now?

BigDave
08-09-2014, 01:02 PM
I recommend that you bring the FC to shock level. At CYA 150ppm, 20% shock level is 30ppm FC. In 26K gallons it'll take 10 jugs (not jubs :o) of 8.25% to get there from FC 0ppm. All at once. Pour the bleach around the pool so it's not concentrated in one place.

Keep the filter running 24/7. Keep FC at 30ppm until you lose less than 1 ppm FC overnight, you have 0 or nearly 0 CC and the pool is clear. Run the pump 24x7 while shocking. Leave the pool cover open if you can - some of the byproducts produced while shocking the pool may damage the cover.

mary jo
08-09-2014, 01:12 PM
OK- bought 12 jugs of bleach this morning. I have 15,000 gallon pool. Should I wait until tonight (after sundown)? Also- how exactly do I test for FC of 30- dilute a pool water sample like I did for the CYA test?

BigDave
08-09-2014, 01:15 PM
I just re-read about the Tuesday pool party - perhaps you should wait until after the party to shock. In that case, pour 5 jugs 8.25% and be ready to add more. Test FC/CC twice daily (early morning and evening). Add bleach as needed to keep FC at 15. If it drops below 8, test / dose more often. FYI each jug of 8.25% bleach will add about 3ppm FC to your pool.

Don't add any more tabs to chlorinator.

I just noticed that you pH is a little low - Add a box of Borax (20-Mule Team - laundry aid). You won't get accurate pH readings while FC > 10.

Keep us posted.

P.S. Why do you cover the pool at night?

BigDave
08-09-2014, 01:17 PM
OOPS! I thought you said pool was 26K gallons - 15K is different.
I'll post again in a minute.

FormerBromineUser
08-09-2014, 01:23 PM
BigDave: while you're calculating, is there any additional issue with her CH being so high (750)?

BigDave
08-09-2014, 01:27 PM
OK. So...
To start shock, add 6 jugs 8.25% bleach to go from 0 FC to 30ppm FC.
or
To get through party first, add 3 jugs 8.25% bleach to go from 0 to 15ppm FC.

Each Jug will add a little over 5ppm FC.

I would add a half box of Borax.

Also:
Sorry about that! Your first post said "15,000 SF rectangular" then I scanned for a volume and, apparently, found FormerBromineUser's volume - My Bad.

mary jo
08-09-2014, 01:32 PM
Oh- I forgot to respond earlier to this: When I tested for CH it turned purple (after about 40 drops) instead of blue, so I just kept adding drops until I saw blue (with small particles of purple swirling around). I looked this up in the Taylor booklet and it said this is caused by metals (copper?) in the water… btw: My city water is supplied by 3 city wells treated at a city water plant, and is characteristically HARD. Alot of homes have water softeners.

BigDave
08-09-2014, 01:34 PM
BigDave: while you're calculating, is there any additional issue with her CH being so high (750)?I asked if that could be testing error

@mary jo: Did you retest CH? Perhaps you should add a Tablespoon of Borax to test bucket to see if it clouds before putting it in the pool. Put something dark in bucket - you may not be able to see a cloud in a white bucket.

BigDave
08-09-2014, 01:36 PM
... this is caused by metals (copper?) in the water ... Maybe it would be safer to add a half cup of bleach to the test bucket to be sure we can't force the metals out.

mary jo
08-09-2014, 01:42 PM
BigDave: My daughter thanks you (as do I)!!!! I will do as advised.

oh- Why am I super diligent (crazy) about keeping the pool covered- especially at night????
Main reason I got a pool was for my youngest (I have 4) who has special needs. Also the main reason I paid big bucks to get an automatic pool cover. He loves water but can be impulsive and loves to get up early (4:30am) and get into trouble. Twice during pool construction (during excavation) he ran out and attempted to jump into the hole from our deck.

But I read about the chemical build-up that occurs during shocking so I will be extra careful in keeping him away from the open water, and keep the cover open until this chlorine issue is resolved.
thanks again.

BigDave
08-09-2014, 01:47 PM
With that safety issue, I would keep it closed and deal with the consequences. If there's damage, it's only money.

mary jo
08-09-2014, 02:44 PM
funny- that's what my husband always says….
I'm a night owl so I can keep the cover open til about 2am, then close until morning.
i have the test bucket with pool water & 1/2 cup bleach in it. Will let you know tomorrow what happens.
thanks

FormerBromineUser
08-09-2014, 04:17 PM
.
You have a VERY important reason to keep your cover closed at night. There are other advantages too.

I almost always keep my cover closed at night: It helps keep in heat and that has been a real advantage with the cool weather this year! It helps keep critters from finding the pool at night; I never find dead toads, chipmunks, voles, etc. unless I leave it open. If a storm comes up at night, windblown debris stays out. (I rarely have to vacuum because I also close it during the day if there's any type of strong wind).

I leave it open: If my water level is low and it is going to rain with little to no wind. If the pool water temperature gets high and I need to cool it off. If I have to go to shock level. I also left it open while I was lowering my TA and aerating with my fountains.

Good luck with your pool and the party!

mary jo
08-11-2014, 10:17 AM
Good Morning; I wanted to touch base and let you know how it was going, in case I'm was off base or spinning my wheels. Here's where I'm at: SATURDAY evening added 3 jugs of bleach, by next morning @ 7:50am and got CL=.5, CC=1.0
Here's my log:
SUNDAY:
8am added 3 jugs
test @ 9am CL=18 CC=1

test @ 12 noon CL=5.5 CC=1
added 2 jugs

test @ 2:30 CL=9.5 CC=.5
added 1 jug

test @ 5:30 CL=7.5 CC=.5
added 3 jugs

test @ 8:30 CL=13 CC=.5
added 1 jug

test @ 11:50 CL=10.5 CC=.5
added 3 jugs

MONDAY:
test @ 7am CL=10 CC=.5
added 1 jug

test @ 9am CL=12.5 CC=0
added 1 jug

SO- it seems Saturday the pool was steadily losing approx 2.5 ppm CL/hour, right? Today its losing less, but still early in the day (a rainy one at that). Is that how it's supposed to go? Am I on the right track?

BigDave
08-11-2014, 11:08 AM
How does the water look? Still clear? No stains?

Did you happen to test pH when the FC was below 10 yesterday?

Sounds like you are on the right track. The only chlorine demand I recall like this was caused by ammonia that was the result of bacterial conversion of CYA over winter. Maybe your pool got into this situation, the bacteria could grow unseen turning CYA into ammonia if the active chlorine was low enough. I would, however, expect to see visible algae if the chlorine / CYA ratio was so low. Maybe it was the fertilizer.

Does the pool water stink of chlorine like a heavily used indoor pool (after the cover's been open a while) or does it have little smell?

mary jo
08-11-2014, 12:22 PM
The water is still very clear. No slimy feel on the walls or floor. There is no heavy smell of chlorine at all. No staining at all. (The bucket test w/ 1/2 cup bleach had no stains either).
I did test the ph on Sunday morning after I added about 2 lbs pH up to the pool sat night ( several hours before adding the jugs of chlorine). It was 7.8. The water clouded when adding the pH up but dissipates in about 2 minutes.
I did test the cya to day and it's at about 140. Is that possible considering it was so high a few days ago?

CarlD
08-11-2014, 02:29 PM
I don't know how this thread got closed, but I have reopened it.

CarlD
08-11-2014, 02:40 PM
Mary Jo, I haven't been following this thread but I noticed you are using pH Up! You should know three things about it:
1) It will raise you t/a as well as your pH
2) Because of that we generally recommend using Borax instead ( yes 20 Mule Team Borax!)
3) pH Up! is EXACTLY the same as Arm&Hammer Washing Soda (next to the Borax in the laundry aisle), being Sodium Carbonate or Soda Ash, only it costs 3x to 4x as much as Washing Soda.

FYI

mary jo
08-11-2014, 02:53 PM
Yes, I read about that too late….! I bought a bunch of "stuff" from my (former) pool store guy before I found The Forum... 25 lbs of pH up is what they recommended. My pool's pH has been low all season, however TA has been about 80-100 level (until just recently it went up to 120). I still have 10 lbs left so I thought I'd use it up. Didn't realize it had extra stuff in it. I'll get Borax for next time.
thanks for the info.

BigDave
08-11-2014, 03:08 PM
Let's not add anything to raise pH or TA for a while. I'd like to see it come down. Half a box of Borax would have had about half the effect on pH and little effect on TA. Right now (your cloud proved it) your pool is dangerously close to precipitating calcium either as a cloud in the pool or onto your heater or as scale at the waterline.

The CYA test is hard to read, I'd call 140ppm the same as 150ppm.

Keep the FC at 15ppm with bleach, if it drops below 10, check pH. Enjoy the party if you can - pool parties at my house are pretty stressful for me - I count heads alot. I really only relax when the pool gate is locked.

mary jo
08-11-2014, 07:17 PM
Yes I am a giant stress ball during pool parties- and I haven't had that many yet! I wanted to ask about safe chlorine levels for swimmers in my pool. I read ( and re-read) the info about CYA /free chlorine levels , but wanted to double check with you. What is a safe FC level for swimmers given my high cya? Oh- pH is currently 7.6

BigDave
08-12-2014, 09:20 AM
At 150ppm CYA, the pool is safe between 8 and 15. I don't recall if I've asked you to look at the Best Guess Chart (http://pool9.net/cl-cya/). It explains the relationship between CYA and chlorine.

How does the pool look? Did you measure FC / CC this morning?

mary jo
08-12-2014, 09:40 AM
Good Morning! At 10:00 last night I put 2 jugs into the pool to bring the FC high enough so that I would be OK until this morning. At 8 the FC=9, CC=.5 The pH=7.6 (so I'm losing much less FC per hour today!)

I found the Best Guess Chart and it makes perfect sense to me, but I guess being told for years that you "never, never, EVER want to swim in anything higher than a 4 or 5..." takes some getting used to.
I know you guys must get this all the time, but it's really like we're Neo (from the Matrix movie) and you're Morpheus and we've just taken the red pill….strange indeed.
But I get it now.
Fingers crossed for good weather- it's cool and 40% chance of rain. Can't control the weather…….
Thanks for all your help!

BigDave
08-12-2014, 09:56 AM
You may want to push the FC a bit higher before the guests arrive. You're still losing chlorine at a pretty good rate and a bunch of swimmers will only increase the demand.
Pool Party Hint: If you make all the kids get out every 45 minutes for "adult swim", you'll get less pee in the pool and less chlorine demand.

mary jo
08-12-2014, 10:07 AM
OK- I will do that.
I want to turn the heater back up- I usually keep the water temp at 84-86 for swimmers. Will I have to compensate for that by adding more CL?

Watermom
08-12-2014, 10:10 AM
No. Shouldn't make any difference.

CarlD
08-12-2014, 02:11 PM
Yeah, colder water doesn't start to inhibit algae growth till it gets down to about 60 degrees F. Heat CAN break down chlorine, but that's got to be hot tub temps first.

FormerBromineUser
08-13-2014, 12:11 AM
.
Hope your party went perfectly except for the cool weather. Bummer!


I just re-read about the Tuesday pool party - perhaps you should wait until after the party to shock.

Just a thought here. If you decide to take your pool to shock level and follow the overnight test procedure, you may want to do one more thing. :tired:

If you have underwater lights (which I think you may), and haven't yet cleaned them, consider doing this:

While FC is high, unscrew and release the lights. The screws SHOULD be only lightly hand-tightened for ease of removal. Scrub the cords, screws, in the niche itself, everything. Leave the lights off for a while and let the high-chlorine water really get into the light niche(s). While you're doing this, you can soak the light housing(s) above the pool in a bucket of chlorine-saturated pool water.

Water sits behind those lights with very little circulation and can harbor all sorts of nasty stuff that can contribute to chlorine demand. Cleaning behind lights is one of those occasional maintenance items that often doesn't get done or done often enough. Shock levels are the perfect time to do this.

mary jo
08-14-2014, 11:27 AM
Timing is everything…I ended up in the ER with my mom all day Tuesday, so the pool party was moved to Wednesday- which ended up being a much warmer day. In the end, all went well. FC level went from 13 to 8 over the evening, so no worries about un-sanitized water.

Today, however I ran out of the FAS-DPD chlorine testing liquid. I called all pool stores in the area and they, too are out of stock. Thank goodness for Amazon Prime- a big bottle will be delivered on Monday. I do have the another Taylor chlorine testing kit (K-1004), and I can dilute the pool water with distilled to get a reading up to 5 and multiply from that point, but not sure I should do this when shocking all the way to 30 due to accuracy. Should I wait and continue maintaining a FC level of 15 until my supply comes in and shock to 30 on Monday night?

Cleaning the lights sounds daunting to me! Once again the pool installers told me I wouldn't have to worry about cleaning/changing lights for years. But I will check into it. Thanks

FormerBromineUser
08-14-2014, 11:52 AM
Let's see if an expert chimes in here about accuracy and stuff.
If they think it's necessary for you to start right away with the more accurate testing, I have an extra 2oz of R-0871 that you could use and refill for me when you get your big bottle :) Just a thought. I tried to send you an email (I don't have yahoo im) with my contact info.

BigDave
08-14-2014, 12:32 PM
... FC level went from 13 to 8 over the evening ...During the party?


I hope your mom's OK.

Are using the 25ml sample for FAS-DPD testing? You can save alot of reagent by using a 10ml sample and multiplying drop count by 0.5ppm. If one scoop turns the sample pink, you don't need two.

Not that I'm an expert, but... You can use the patented CarlD shot glass dilution metod of chlorine testing to get a start this weekend. Mix 5 shot glasses of distilled water with one shot glass of pool water then test the mix for chlorine and multiply by 6. Not accurate enough to know when your done but good enough to start the shock process.

mary jo
08-14-2014, 02:12 PM
Thanks, BigDave. My Mom lives with us so I'm keeping an eye on her and the pool now.

At 3:00 yesterday the FC=15. At 10:00 the FC=8 (using the FAS test). It lost about 3/4-1" of water - lots of splashing...

Considering this is the last weekend before school starts, I wanted to hold off on shocking the pool to 30 so the kids can swim more. Do you think my pool will be OK if I maintain 15FC level over the weekend?

BigDave
08-14-2014, 02:31 PM
Sure, it's your pool and family. Realize that if there is something growing you may be spending all this bleach without making any headway. Since there's no smell or visible algae and we really don't know the cause of the chlorine demand, keep FC above 8ppm, preferably 15ppm. It is probably beter to clear ir up before you close.

mary jo
08-14-2014, 04:29 PM
Yup- I hear you. I want this solved even if it means investigating the lights. I will define keep FC level up to 15 and shock to 30 on Sunday evening, keep it at 30 for at least 24 hours and go from there.

We don't close our pool until late September so I have about 6 weeks to clear things up.