Introduction- Chlorine problems

[Pieface2000]

Hello, I have an 18,000 gal. vinyl pool. Have it for 3 years. Live in Bear Delaware.
When I opened my pool this year it looked like a neighborhood pond. Never saw anything like this before, I'm am still a beginner.I used about 6 de change outs till pool cleared up to where i was able to vacuum it out.That was back in early may.I would vacumn pool weekly.I believed that all my pool chemistry was correct, I use the strips and also verify with test kit.I have been noticing some algae on the pool line ,pool water was crystal clear to the naked eye. I brought sample to pool store to verify, last 2 months I have been not happy with maintaining chlorine levels, I have a feeder, at highest setting.Have been changing out De about 4 times in last 3 months, pool doesn't get much activity. just weekends never crowded.
Pool analysis
cl-.1
fcl-.1
alk-0
ph 7.0
hardness -0
phos 2200ppb

New pool results
cl-0

 

[Pieface2000]

Sorry hit the wrong key
Alk-150
Calcium hardness 300
ph-7.4
cl-0
fcl=0
cya->100

I have put about 8lbs of shock in since yesterday and intially I get a chl. reading then an Hr. later its gone. I have added some phos free yesterday after backwashing and dumping DE,and replacing DE. Looking for any suggestions to get chlorine level Back.
Should I keep shocking?? Dont know phosphate results yet. By the way pool water looks crystal clear.
Please send help!!!

 

[AimeeH]

Hello and welcome to TFP

The first thing we will tell you is to take care of (control of) your pool is your own quality test kit. Chlorine is what you need in the pool to kill algae and clear it up. Those are pool store test results which we don't like to trust.....particularly the CYA test by pool stores.

But.....if they are correct on your CYA, that is way out of range for easy maintenance. And it sounds like you may be adding more by using powdered "shock." Your CYA could be way over 100 even. The amount of chlorine you need depends on that CYA number.

Start by reading up in pool school here

Pool School - ABCs of Pool Water Chemistry
Pool School - Test Kits Compared
Pool School - Chlorine / CYA Chart
Pool School - SLAM - Shock Level And Maintain

 

[Texas Splash]

^^ I couldn't agree more with Aimee's recommendations. Stay away from the pool store or you'll be chasing your tail and spending way too much money. Test the water on your own - it's easy to do with one of the recommended test kits and that kit will pay for itself 2-3 times over. If you find that your CYA is indeed really over 100, the only way to lower CYA is by water exchange. You can thank the pool store and their tabs/bags of shock for that one. :grrrr:

Oh, don't be alarmed, but we deleted one of your duplicate posts to keep everything together on this similar topic and avoid confusion. Nice to have you with us!

 

[atttech-2]

Welcome! For some this can all seem overwhelming at first, if you get a good test kit, read Pool School, and ask questions as you have them it will make sense in short order. Ignore the phosphates many pool stores will point to them as the cause of algae while it is true they are "food" for algae they do not cause algae blooms. Once your pool is free of algae by going through the SLAM process and if you keep your chlorine level in the range of the chlorine / CYA chart that Aimee posted, the phosphates become irrelevant. The little buggers find it hard to eat when they are dead form a properly sanitized pool.

 

[Pieface2000]

Thanks,
I do use the taylor test kit. My CYA level has always been Higher than 100, probably around 150 or more.Since i tested when I opened pool.I have been putting the powdered shock in, I have 3 lbs. left,stores are closed. I was told the cya would go down, but obviously it hasn't.Should I use a liquid shock or just keep putting the bags in? That explains why I cannot keep a good chlorine level. Thanks for all your help

 

[Texas Splash]

Anytime the CYA is over, it requires more FC to compensate to the point you just can't keep enough FC in the water. So the ideal solution is a partial water exchange to get the CYA back under 100. Yes, those pool store products did that to you. For daily chlorination, I would only rely on liquid chlorine or regular bleach (same thing). They are some of the best sanitizers with next to no side effects or added chemicals. For your CYA, you might want to try the diluted test:

CYA Dilution Testing:
Add pool water to bottom of sticker.
Add tap water to top of sticker.
Shake.
Pour out half so mixture is to bottom of sticker. (or 7ml line)
Add reagent to top of sticker. (or 14 ml line)
Shake.
Test outside with back to sun and tube at waist level.
Pour back and forth a few times to see if you get the same result.
Double the result.

 

[Pieface2000]

Just rechecked the cya with dilution method, its about 160, that was great info thanks. Right now im showing 3 chlorine and a 3 fc, but its going to vanish, shocked an hour ago. Should i just drain water? Going to start using liquid bleach after i get this cya under control.

 

[AimeeH]

Just rechecked the cya with dilution method, its about 160, that was great info thanks. Right now im showing 3 chlorine and a 3 fc, but its going to vanish, shocked an hour ago. Should i just drain water? Going to start using liquid bleach after i get this cya under control.

I would definitely want my CYA lower, so if you can drain and refill I would. You can use pool math (link at top of page) to calculate how much to drain based on your target. You may want to do several partial drains and refills as you don't want an "empty" pool with a vinyl liner.

 

[Pieface2000]

Used pool calculator for cya, drained about 18 inches of water, a little nervous about taking level down too far having a heat wave here. I'm filling back up. 17200 gals. cya was ~160-180, with dilution sample results, Hopefully this helps. Is it ok to start using pucks once cya level gets in range, or just use the liquid bleach? My pool is 16X32 and average of 4.5 feet total. Too bad there isn't a cya removal chemical. What type of shock do you guys prefer to use? Thanks for all your info in advance.Should I be dumping in liquid bleach now or wait for fill?