Noob - Free Chlorine Issues

[andysousa]

Hi all!

First and foremost... I am a new pool owner. We bought a house this past winter with an in-ground pool and I still have A LOT to learn. I have been trying to keep up here the best I can while also working with a local pool shop. I am getting a little concerned about the advice I am getting from them and wanted to share my experience with the hopes of getting a little advice as well.

We opened the pool on May 8th. When they opened the pool, it was crystal clear! Woohoo right?? They added a little liquid shock and said good luck and went on their way.

I started testing the pool that week with Poolmaster test strips... notices things in general were really low (pH, Alkaline, and Hardness). Brought a sample of water to the local shop... they confirmed it.

They put me on a 3 day treatment of Hardness increaser and alkalinity increaser. The brand of chemicals is Life Line. 3 Days later... all good in that department, pH, alkalinity, and hardness all spot on. Total chlorine still on the low side of ok and the free chlorine barely registering.

Took another sample back... they confirmed it... now time to work on Free Chlorine. They said the pool must be high in ammonia... so they instructed that I put 12lbs of Refresh+ granular shock into the pool. I did this last night... took a test just for fun, and the free chlorine was glowing bright purple on the test strip off the charts. I am thinking this has to be good!!!

This morning, I got out to the pool... quite a bit of granular on the bottom of the pool still ... that scares me as it is a vinyl liner. Do another test... free chlorine and gone (white on the test strip) and the total chlorine is back to the low side of ok.

So I am going to try and get back to the pool store today... but was hoping some one in here might have some wise advice for me. Seems like 12lbs of shock should have done the trick... especially seeing as there is still quite a bit on the floor of the pool. Any next steps I should take? An advice for a noob at all here? Sorry if I am not clear... I am still learning a lot as we go here.

Oh, should also note the pool filter has been running since last Saturday when I started this adventure.

TIA!

[Denniswiseman]

First of all stop going to the pool store for advice, they are there to sell
Stop buying all of their products
Next get a decent test kit (Taylor K2006c or TF100)
Then lets have your numbers
FC:
TC:
pH:
TA:
CH:
CYA:
You probably need to Slam after checking Chlorine / CYA Chart
When the slam (Shock Level and Maintain) is done set your Pool Levels
For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm
All the chemicals you should need
Liquid chlorine (sodium hypochlorite or plain bleach)
Muriatic acid (hydrochloric acid) to lower pH and TA
Bicarbonate of soda to raise TA
Aeration will raise pH only

[andysousa]

Hi Dennis,

Thanks for the reply. I will invest in the kit you mentioned, but in the meantime here are the numbers based on the reading I got from the pool store. Again, this is after the 12lbs of Refresh+ which went in last night.

FC: .36
TC: 2.92
pH: 7.4
TA: 115
CH: 232
CYA: 80

Tonight I added 4 gals of liquid shock (sodium hypo) just because I had it....

I am guessing based on all these numbers, there is a way to get this cleared up? Seems like based on what I can piece together on this site, the CYA is high.... but I am still struggling to put the pieces together. Any help would be appreciated.

[Denniswiseman]

Based on your pool store numbers numbers you have a lot of combined chlorine
Based on a CYA of 80 you will need to Slam at 31ppm chlorine unless you you do a partial drain and refill (CYA will deteriorate over time with backwashing and rain but there is no chemical way to lower it)
pH is fine
TA could be reduced but not a problem
CH is ok with a viny pool
The sodium hypochlorite wont do any harm apart from raising your chlorine level which you need to do (31ppm)
But how old was it as it deteriorates over time and could be just salt water if its very old
Remember that you have to maintain the shock level of 31 untill you pass all three criteria
After the slam if you keep your CYA at 80 you will have to target 9-11 ppm chlorine with a minimum of 6ppm
Get plenty of liquid chlorine and use Pool Maths to work out how much to put in with regard to the different strengths

[andysousa]

Thank you for the reply... if you don't mind me asking an add-on question here Dennis

If my math is correct, the 12lbs of Refresh+ that they asked me to put in should have brought me well over the 31ppm right? Each bag says 5-10ppm per 10k gallons. So with my 20k gallons, it would in theory take my pool to 30-60ppm right? Not trying to be a PITA, just trying to figure all these numbers out.

Andy

[Denniswiseman]

Hi Andy
No problem, I had quiet a few issues and other more knowledgeable pool users helped me, there are a lot of old ideas out there that have been proven wrong (slug of acid in the deep end, shock every week) but people still think that's the way to go

It may well have done to start but got eaten up pretty quickly (5-10 is a pretty big variation)
Does that Refresh contain CYA if so you are putting your chlorine Slam up higher
That is why you have to test often and accurately, maybe every hour untill it holds, hence your own test kit
Remember SLAM Shock Level And Maintain

[andysousa]

Ok, went with the liquid chlorine and I am happy to report that my free chlorine has been rock solid for almost 3 days now. Still waiting on my kit to give the actual numbers but free chlorine and total are resisting nice and high on my test strips. Looks like I have finally gotten rid of whatever was eating it up!!

So again, I am a complete noob but based on the numbers and what you said my goal is to keep free chlorine between 9-11 right? Once the cya comes down over time I can cut that back based on the chart.

The peices are slowly starting to come together for me

[Denniswiseman]

Hi Andy
Depending on your water costs it can be more economical to do a partial drain and refill to keep your chlorine costs down but keep your slam levels up until you pass all three slam criteria
You have got a good grip on the process and once you get your test kit you will become another expert