Can't Maintain Chlorine Level

[DripSZN]

Good morning, I am a new pool owner (of a used pool) and have had trouble trying to figure out the issue with my chlorine by myself.
I have a ~18,000 gallon pool and the water has been clear since I got it in February.
There have been no signs of Algae from what I can tell. (I have attached a picture from my security camera)
Ever since February all the FC/TC readings from Leslies have come back at 0 ppm.

I tried to clean out my inline chrloinator, patched up a minor leak (micro crack that had 1 drip every 20 seconds) on the chlorinator, verified the hoses were not plugged from the chlorinator to the return plumbing.. and still no chlorine.

I finally purchased a 20 pack of the In the Swim pool shock and added 6 lbs of it to the pool at the end of March.
I let the pump run for 8-12 hours and caught a sample to take to Leslies. I finally got a TC/FC of 1 ppm.
A few days later, I took another sample and the TC/FC was at 0 ppm....

Does anyone have suggestions as to what I can try next or seen something like this before?

I have attached all my results from Leslies as well as the pool equipment set up. . .

 

[mknauss]

Welcome to the forum!
TFPC advocates that the pool owner does their own water chemistry testing using a proper test kit.
Order a TF-100

The only other real option for a test kit is a Taylor K-2006-C. Be careful comparing prices because the K-2006 comes in sizes, designated by a letter. The basic K-2006 has .75oz bottles. You need to get the K-2006-C to get the larger bottles that you want.

I also have the Speedstir. It makes testing much easier.

I suggest you add 5 ppm FC worth of liquid chlorine each day to the pool until you get your test kit and post up the results here.

I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.

 

[Jimrahbe]

Drip,

You do realize that the chlorine in your pool water gets used up the same way gas in you car gets used up?...to keep your pool running, you need to continually add new chlorine.

I assume that you are using 3" tabs to add chlorine to your pool, but since your CYA is already 70, the more and more tablets you will have to use to add the chlorine you need. Unfortunately the more tabs you use, the higher the CYA gets which just compounds the issue..

To confirm if you have algae or not you need to do an OCLT Overnight Chlorine Loss Test But to run the OCLT test you need to have an accurate test kit. The lack of an accurate test kit and the lack of understanding how a pool works is the number one reason for most of the issues that pool owners have..

I suggest you read our Pool School and see what we are all about.

Thanks,

Jim R.

 

[DripSZN]

Yes sir, I understand it gets used up.. but I can't believe it is getting used up faster than the tablets are adding it in from the chlorinator?

Is a CYA of 70 high, do i need to drain the pool water and add fresh water to decrease the CYA to 20-35 ppm?

Thank you for your input! I will read through the "pool school"!

 

[Texas Splash]

Hey Drip! Welcome. Like mentioned above, I too highly recommend the TF-100 (link below) - with speedstir if you can. There's no subtitute for accurate home testing. Also, stay out of the pool store. They'll have you chasing your tail and spending lots of $$$. Theres no need. You can trust the TF-100. I wouldn't do any drastic changes to the water until you test it yourself. The CYA test is often wrong at the pool store. But if you have tabs in there, remove them now. Grab some regular bleach/chlorine. I used to go to HEB for their Bravo, but they just lowered its % strength, so I got my last batch form Home Depot (10%). Either way, use pool chlorine (bleach same thing) to increase your FC. Summer's on its way, so you'll want a healthy CYA - probably 50-ish, but don't trust the pool store's test. Get the TF-100 and post back. We'll walk you through it.