Why did my bleach leave?

[philanna]

Hello, I'm new to this forum and a new pool owner. I recently decided to go the BBB method. I was using a pool service(it came with the pool). After reading and learning here I decided to do it myself using the BBB. The pool service had my CYA at 100+, he would add liquid chlorine once a week and he would fill the floater with tablets, pucks, whatever. The problem (IMO) was that we would be out of chlorine by like Monday and he came on Wednesday. So I started on my own this week and I need your help!
I drained some water and added fresh (tap). My CYA is at 90, I know this is rather high so this weekend my DH is going to help me and we'll drain some more. I'm thinking my CYA should be around 40, so I can keep my chlorine at 3ppm.
Heres my #'s (I'm using the Taylor K2005 kit):
Thurs night--
FCL=0
TCL=.5
PH=7.4
ALK=90
CAL=290

Then I added 1.42 gallons of 6% bleach(I was shooting for 6ppm, since my CYA is 90)

Waited about 2 hours, then--
FCL=5+(very pink)
TCL=5+(same very pink)

Ok now this morning @ 7:00 a.m.--
FCL=1.5
TCL=2.0
PH=7.4

Where did my bleach go? Do I need to shock?
Thanks in advance,
Anna

Oh ya, my pool is 16,100 gallons. IG-PebbleSheen-attatched raised spa.

[aylad]

Yes, you need to shock it. Since your Cl was so low before, odds are good that you have an algae bloom trying to happen (or there's something else in your water that is causing the large demand). I would shock the pool to 25 ppm, and hold it there until it quits dropping substantially overnight, then let it drift back down. if you do a partial drain/refill this weekend, then when you refill it, retest your CYA and adjust your shock level accordingly (see the best guess chart stickied at the top of the chlorine section).

Janet

[philanna]

Thanks Janet. My kids are leaving on Sat. afternoon so I think I will wait to shock till then, its hot out and they have a friend over to swim. I'm thinking I'll add some bleach this morning and tonight to try to keep it up to like 6, that way they can still swim today and tonight. Then on sat. we will drain some and refill and then shock to whatever the best guess cya chart recomends and then hold that # till it stops dropping overnight. Do you think that would be an OK way to go? Or do I need to deal with this right now, and just tell the kids "sorry no swimming" ?
Should I even bother adding any bleach right now, cuz the sun is about to be on pool in like 30 minutes. Is it better to add it even if I know its gonna leave, or should I just let it go till tonight?
Thanks again for your help, and sorry if my ?'s are stupid.
Anna

[aylad]

Yes, you do need to add the bleach now, even if you know it's going to "leave"--if there's no chlorine in the pool, it's not sanitary for kids to swim in it. In fact, you really need to keep adding as necessary to maintain the 6 ppm for as long as they'll be in it.

Draining and refilling over the weekend is a good way to go....then adjust your shock level according to the table and shock at least through the end of the weekend. I wouldn't wait any longer than that to shock it, though--if the chlorine demand is that high now, whatever you've got waiting to bloom may get a step ahead of you and then be harder to kill off.

And no, your questions are not stupid--I'd much rather you know what to do now, than wait until your pool is pea green soup and THEN try to clear it up!!
(It can be done, but I'm glad you're heading off the problem before it gets that bad)

Janet

[philanna]

Thanks again Janet. I'll watch it all day and add bleach as needed. I'll report back after this whole drain & shock business.
Anna

[philanna]

Goodmorning,
Ok so we drained and diluted our pool all night Fri. and Sat. morning.
I added some bleach Sat. even though we were still draining/diluting just to keep anything from blooming.
I had to go to pool store to get reagents, so I had them test water;
FCL=5.0+
TCL=5.0+
PH=7.6
ALK=90
CAL=160 (way off my #'s)
CYA=40 (way off my #'s)
TDS=1500
COPPER=0
Heres my #'s that I took about an hour later;(4:30p.m.)
FCL=9
TCL=9
PH=7.6
ALK=80
CAL=250
CYA=70
Here are my 9 pm #'s (i didn't add any more bleach yet, i wanted to see if it would hold at 9ppm.);
FCL=6
TCL=6
PH=7.6
ALK=80
CAL=210
CYA=60-70(this is a hard test for me, my eyes suck)
Ok so the chlorine did'nt hold so I added 3.7 gallons, then i retested chloine at 9:45, it was at least 20ppm, i think closer to 25, but thats with alot of dilution from shotglass method.
Now here are this morning test results;
FCL=20(AT LEAST)
TCL=20
PH=8
ALK=90
CAL=220
CYA=70(maybe 60, i suck at this test)

Now then from all I've read I should go by my results over the pool stores, so I say cya=70. My chlorine held all night. So now do I just need to add muratic acid to bring my Ph down? Should I shoot for 7.4?
And since my cl stayed all night am i done shocking? I have to leave today so I won't be able to test or add anything between 11am and 7 pm.
Thanks in advance for your help
Anna

[waterbear]

Your numbers have been relatively consistant. I would trust them over the pool store. I work in one and have seen very bad test results done in pool stores! You pH is fine at 7.6 but you really can't test pH accurately until your chlorine levels drop below about 10 ppm! If you chlorine held overnight I would let the levels drop and then retest. BYW, if you look on the lid of your taylor kit on the bottom of the chlorine test section it it will tell you how to dilute for testintg high chlorine levels....there are dilution markings right on the comparator for 1:1 and 1:4 dilutions. You don't need the shotglass!

[philanna]

Thanks for the quick responce. I'm glad I didn't just add acid without asking, this forum rocks!!! Wow, I can't believe I didn't read that on my Taylor box lid, I thought I've read everything like a hundred times . I'll test agian tonight, and I'm sure I'll be posting my numbers to make sure I'm OK.
Anna

[philanna]

Oh ya, should I leave my filter running untill my chloine level drops? Or should I let it run its normal cycle (8hrs per day) even though my CL is 20?

[chem geek]

It is possible that having your pump run 24/7 until the chlorine level drops might help make the chlorine level drop a little faster due to better mixing (bringing higher chlorine levels closer to the surface where it can get broken down by sunlight more readily), but this might be a minor effect. So the real answer is, "I don't know", but having your pump on might help and it certainly won't hurt (except for a somewhat higher electric bill). Once your chlorine is down closer to normal levels, you can return your pump to normal hours.

The main way to bring your chlorine level down is to keep the pool exposed to sunlight as that will break down the chlorine faster than most anything else.

Richard