Chlorine Demand

[gfritz1]

Been three years since posted but the chlorine demand is back. Inground-DE-Vinyl- 23000 gal .Started out season good but now cannot get a FC reading above .5 .Eating chlorine at rapid rate .Last readings 7.0 PH ,.2FC,.2 CC,138 Alk, 80 cya, 258 hardness. Had chlorine demand test 4 weeks ago and came back 92 bags to add . I took option of partial drain and took water down 15 inches. Still same issue but new chlorine demand now says 33 bags. Water is perfect clear and has been . Options:
Do teh 33 bags but what type of shock ????
Do partial drain and another test and then shock? What type of shock?
swithch to Pristimne Blue ?
Fill in pool ?
Comments

[Watermom]

NO to your last two options --- using Pristine Blue and filling in the pool! :eek::eek:

Please fill your pool's information into our pool chart and that will make it easier for us to help.


Pool Chart Entry Form (http://goo.gl/cNPUO)
Pool Chart Results (http://goo.gl/PXaLu)

What kind of shock is it -- meaning ingredients. How high have you been taking the chlorine when you add it? Have you had a recent algae bloom?

Welcome back to the Pool Forum, by the way!

[gfritz1]

Did the Pool Chart Entry Form but could not fill out Pool Chart Results Form for some reason .
I rotate shoch between dichlor-cal hypro-lithium -chlorine free to try to avoid cya increase as in past using hth cal was over 120
Using tri chlor tabs in a side style chlorinator
No algae bloom as pool is crystal clear . I have a chart (excel with all my readings from opening to now )anyway of posting or emailing?
usage on pool is low -mostly adults and about 1-1.5 hrs per day

[Watermom]

You aren't supposed to fill out the Pool Chart results, just the entry form.

I don't know of a way to post an excel spreadsheet. For now, can you just give us the most current readings and tell us the date they were taken?

[gfritz1]

IEntry Form is filled out .Recent results 7/12
CYA 70
PH 7.1
Alk 138
Hard 258
FC .2
CC .2
TC .4

[aylad]

I would not use either dichlor or cal-hypo, because your calcium and CYA are both already high. I would use plain, unscented bleach. In 23K gallons, each 3 quarts of 6% bleach will raise your FC by roughtly 2 ppm. With a CYA of 70, you need to raise your chlorine to shock level, which for a CYA of 70, would be 20 ppm. To get from 0 to 20, that means 7.7 gallons (8 to be on the safe side). You need to test the water as many times a day as possible, and add whatever amount of bleach is needed to get back up to the 20 ppm. Hold it there (the more consistent you are, the faster you'll get there) until you can measure chlorine at night and again the next morning before the sun is on the pool, and not lose more than 1 ppm of chlorine in that time. Then you can let it drift back down, but never below 5 ppm.

I suspect you have algae trying to bloom, and you have been chlorinating enough to keep it at a standstill, but not enough to kill off what you can't see. If you'll shock as described above, it should correct the problem.

I wouldn't use any more stabilized chlorine--no dichlor powder or trichlor tabs. I would switch to plain bleach for your chlorination to keep those CYA levels from getting any higher.

Janet

[Watermom]

To add to the advice that Janet gave you above, your pH is a little low. Use some 20 Mule Team Borax (laundry aisle at Walmart) to bump it up a little. Aim for 7.4-7.6 but anywhere 7.2-7.8 is ok. Start by adding a half a box slowly to the skimmer while the pump is running. Retest after a couple of hours. NOTE --- You cannot get an accurate pH reading when your chlorine level is high. Adjust your pH a little first because with a chlorine level of 20, you won't be able to get a true pH reading.

[gfritz1]

Can I use Lithium shock as have a pile of it?

[PoolDoc]

I don't think it will hurt anything to use it, and it will add chlorine, so yes, go ahead.

[gfritz1]

Janet - will return from work in kY on Friday and will address the pool.Part of my issues is have been working in KY away from home and treating the pool remotely . I am debating about doing a partial drain on my return to get the cya down a little realizing that it is costly . Whats the advantage of doing this or not doing it? I think the cya is probally higher since these readings as have been eating tri clor tabs at a rapid rate

I am looking at using lithium shock since have a supply but unsure enough to raise the leave to 20 ppm and maintain it. Where can I find a formual to calculate the amount needed to bring my pool to 20 at 23000 gals? If I understand correctly I need to start at night and keep feeding the chlorine to keep at 20ppm until the next morning? Sounds like I raise to 20ppm and keep measuring and adding as it drops to get above 20 for a 12 hr period? Then keep at 5 ppm
As for not using tabs you say use bleach .What amount and at what frequency ? Thanks as cant wait to get this behind me. One more questions A&H Baking soda compared to Borax or to PH+ what is the difference as I really need to get my PH up

[Watermom]

In your pool, each gallon (4 quarts) of plain, unscented 6% bleach will add about 2.5ppm of chlorine. Use that as a reference to help you figure out doses of bleach to add. Each time you test the chlorine, add enough bleach to get back up to shock level. You want to keep doing this until you can go from sundown one evening to within two hours of sunrise the next day without losing more than 1ppm of chlorine overnight. Then, keep the chlorine high for one more day for added insurance and then you can let the chlorine drift down and make sure to keep it between 5-10ppm ALL the time. (See the Best Guess Chlorine Chart in my signature up in post #2 for info on the relationship between CYA and chlorine levels.)

20 Mule Team Borax (laundry aisle at Walmart) is used to raise pH and baking soda is used to raise alk.

[gfritz1]

OK THANKS for the help -I did a partial drain upon returning as took down roughly 15inches and refilled starting Friday soi refill was Sunday and Sunday night and Monday added the 20 Mule Team . It took roughly 8 lbs (2 boxes) plus a 5 lb PH+ I had but it is now 7.8 and holding .AMAZING .Last night at dark with a FC of zero added 8.5 gals of bleach and 2- 15000 bags of shock . FC was above 20ppm and by daylight it was still above 20ppm.Extremely sunny day in PA so pool has been in sun all day .It sparkles. My present readings almost 24 hors after super shock FC 12.5PPM CC 0 TC 12.5 PH 7.8 Hardness 190 Alk 140 and cya 72. So FEEL PRETTY GOOD NOW . The chlorinator is off and empty . So what do I do now to continue ? I know you said no more tri chlor or the shocks others then lithium or bleach. What do I use to replace the chlorinator for daily treatment? I assume still add alegcide on weekend and the shock (bleach-how much?) .This is amazing -await your response - GFritz1

[Watermom]

Just use bleach for your daily chlorine. With a CYA of 72 (how did you get that number??), you need to keep your chlorine levels between 5-10 all the time. You do not need to use algaecide and you also do not need to routinely shock unless you are having a CC reading greater than 0.5, cloudy water or see the beginnings of algae. If you maintain your chemistry properly, you rarely need to shock.

[gfritz1]

CYA was measured with the Taylor Test Kit and looking until the Black Spot disappears. The Pool place got 50 using test strips .

Understand to use the bleach so this means daily check of chlorine level and then based on reading add bleach with each gallon expected to raise my ppm by 2.5

Is there a better time to add the bleach? I normally run pump from 7am-7pm and the swimmining usually is from 2-6 but normally only adults doing laps. I understand need to keep higher but like this weekend grandchildren will be here. Whats the safe limit for them to swim-upper ppm level -----thanks again

[Watermom]

The best time to add bleach is in the evening when the sun is off the pool. In that way, all the chlorine can go to oxidizing the goo in the water and none of it will be lost to the sun. However, it is also ok to add it at other times. Especially when a pool is fighting algae, or has a high chlorine demand for some reason, etc.

Keep your chlorine between 5-10ppm. Your grandchildren are perfectly safe when swimming with chlorine at those levels with a CYA of 70ish. (Actually, it is also fine to swim when chlorine is at shock level but you probably would want to wear an old swimsuit if you did so.) People are often afraid that a chlorine level of 5-10ppm is too harsh; but the fact is that with a CYA of 70, chlorine is no harsher at 5-10ppm than it is at 1-3ppm with no CYA.

[gfritz1]

Well its been 8 days since we did the partial drain and the shock using bleach to above 20ppm . The water has remained excellent and the grandchildren were here for weekend and enjoyed three days of swimming .I am losing about 2-3 ppm per day of FC as each day need to add roughly 1 gal of bleach (6%). Is this normal ? Weather was actually more overcast than sun . I have been able to hold between 5 ppm and 9ppm by moring add of bleach.My new readings Sat were as follow
My cya appeared to increase to 80 which I was suyrprised as no tabs are bing used and teh chlorinator is actually turned off
PH is 7.8
FC was 5.6 and CC was o
Alk was 150
Hardness was 170

Have not added anything other then bleach

[PoolDoc]

I am losing about 2-3 ppm per day of FC as each day need to add roughly 1 gal of bleach (6%). Is this normal ?

That's on the high end of normal . . . but still normal. You may find the results improve if you lower the pH some. If you'll fill out the pool chart

Pool Chart Entry Form (http://goo.gl/cNPUO)
I'll try to look and see what you might do to improve the situation a little.

Something else you can try: adding large doses of bleach in the late evening, via the skimmer. This can help clean out any 'goo' in your filter. Again, if you'll complete the chart, I can calculate doses.

[gfritz1]

I initially filled out the pool chart a few weeks ago. Is it not saved?

[Watermom]

Yep! It's there. Sometimes we forget that we have already asked somebody to fill it out with all the people we help each day!

With a CYA of 80, you need to be keeping your FC between 5-10 all the time. Losing 2-3ppm of FC in a day is very normal. In a 23,000 gallon pool, each gallon of 6% bleach will add about 2.5ppm of chlorine.

If you want to shock the pool to try and make sure the filter is clear of any goo, your shock level would be 20ppm. So, use the reference I gave you above to figure out how much bleach to add when you test to take it up to 20. If you can go from sundown one evening to within two hours of sunrise the next morning without losing more than 1ppm of chlorine, have a CC reading no higher than 0.5ppm and have clear water, then you are good to go and can let the cl drift back down to 5-10.

Hope this information helps.

[gfritz1]

I did the 20 ppm about a week ago from sunset to sundown but for sure lost more than 1 ppm so what does that mean? I have been able to hold a FC reading above 5 ppm the last week but until yesterday had been losing 2-3 ppm . Im away again so had my brother in law check pool the night before and it was at 3 ppm so he added like 5 quarts of bleach at sunset and let pump on. Last night was still 7 ppm so will check tonight. question with much time away am I overall better looking at SWG or do all teh same issue stay the same with checking daily etc? Thanks

[PoolDoc]

I initially filled out the pool chart a few weeks ago. Is it not saved?

I'm working on a plan to convert some of the data in the Pool Chart into signatures that will show up each time you post, but right now, it's just a plan. We have to do a search on the pool data, which is getting to be rather large set!

[Watermom]

With a CYA of 80, if you let your chlorine drop below 5, I'd suggest shocking the pool. It doesn't take long for something to get started in the water.

[gfritz1]

Update and a few questions - Reading tonight as it has been holding well since did the drain and 8.5 gal bleach . Tonight PH 7.8 FC 3.6 CC 0 TC 3.6 ALK 140 HARDNESS 140 CYA around 60 All tested with Taylor kit. So what do I add under BBB to raise hardness or domt you worry aboyut it at this level? Would you do anything to adjust AlK a little or leave ? I am using between 3 qt and a gal of bleach a day to keep FC above 5 . Is this normal as at this rate the bleach is about $1.60/day or $48/month ? Would a SWG be less expense to operate ?Water has been excellent

[Watermom]

Where do you live? Some pools in places with really hot climates do better with CYA a little higher.

In a vinyl pool, you do not need to worry about calcium hardness.

Your TA is fine where it is.

An SWCG is a very costly unit. It would take a long time to recoup your cost as opposed to just using bleach, but some people really do like having them.

[gfritz1]

Live in Northwestern PA above State College . My CYA has been between 50 and 80 . At the pool store with strips it looked like 100 yesterday .But using Taylor kit I ended up between 60-70

Thanks

[Watermom]

Trust the Taylor kit's results.

I wouldn't think that in your area you would need CYA higher than 60-70. People who we sometimes suggest that to are those living in the really hot areas of the south. I think you're probably fine with 60-70. However, if you want to bump your CYA up some, you can but if you do so, you'll need to run higher chlorine levels per the Best Guess Chlorine Chart.

[gfritz1]

Has been 3 weeks since started BBB from a chlorine demand condition .Water has remained excellent .I have had to add bleach each day to get back up above 5 ppm as normally find between 3-4 each day. Averaging roughly $1.03/day based on GV bleach at $2.98 for 1.45 gal

Starting to think that closing is less then 4-6 weeks and was wondering what the process is with the BBB method? I have inground and use a Loop Lock mesh cover for winter .Will close for sure by Oct st as here in Western Pa the nights are allready in 50

[Watermom]

There are a couple of threads you can read. Then, come back if you still have questions about closing. By the way, do you have inground or above ground. Your sig says AG but your post says inground.

http://www.poolforum.com/pf2/showthread.php?5911-Closing-an-IG-pool-for-the-Winter

http://www.poolforum.com/pf2/showthread.php?5720-Closing-an-AG-pool-for-the-winter

[gfritz1]

inground

[PoolDoc]

I'll update your signature, if you enter an updated Pool Chart record:

Pool Chart Entry Form (http://goo.gl/cNPUO)

I'm guessing you have the K2005 (DPD color match) rather than the K2006? You should indicate that as well.

[gfritz1]

Really spoke more about draining the lines etc etc then it did about chemicals .Normally when closing a chlorine pool with winterizing kit you have the shock-the stain preventer-some type of floater that has something in it and a algae preventer . With BBB chemically what do you do ?Also normally I have been adding when on chlorine tabs a algicide weekly like back up . My understanding with BBB I do not need to do this ? Presently all I have been adding is the bleach each day and keeping my FC above 5 due to my cya. Normally each day it drops back to 3.4-4.4 and then I add between .5 and .75 gals. Water has been excellent and it has been bonus days in Pa as water is 86 .Closing is withing next 3 -4 weeks so getting ready thus reason for questions. My winter cover is mesh

[aylad]

I don't close my pool, but I think the general consensus is to shock the pool, add a dose of Polyquat, and wait a day, then bring the chlorine levels back up...and then cover the pool. The earlier you open in the spring, the less chance there will be for a mess on opening--I think most folks try to open as soon as they can while the water is still cold.