Chlorine Question

[tenyc424]

I just tested my water tonight and noticed I had no FC. Last week when I added bleach it was at 5 and today it is at zero. I wanted to know how long does chlorine last. We did have some hot days followed by some rain yesterday. But I wouldn't have expected it drop so fast in a matter of days. I did add 1 gallon of bleach tonight and will add some more tomorrow per the pool math calculator. I don't think I have an algae problem since the water was clear and didn't notice any algae. However after the rain yesterday my pool did turn cloudy. Would appreciate any advice.

My readings are.

PH- 7.6
TA - 150
CH - 300
CYA - 70-80 Ive gotten different results each time I do this test. I'm going to my local pool store to try and get a more accurate reading

For my tests I've been using the taylor k-2006 with the fas-dpd

 

[Husky25]

You'll lose 3 ppm of Chlorine from the sun alone. 5ppm won't last a day and a half. I add 1/2 gallon of 12.5% LC per night for about 21,000 gallons of water.

With a cloudy pool, you'll need a SLAM. The rain isn't as responsible for the cloudiness so much as the lack of chlorine. Depending on your CYA level, chlorine should not fall below the minimum FC.

 

[tenyc424]

You'll lose 3 ppm of Chlorine from the sun alone. 5ppm won't last a day and a half. I add 1/2 gallon of 12.5% LC per night for about 21,000 gallons of water.

With a cloudy pool, you'll need a SLAM. The rain isn't as responsible for the cloudiness so much as the lack of chlorine. Depending on your CYA level, chlorine should not fall below the minimum FC.

Didn't realize the pool would need that much chlorine. I just started converting to bleach not too long ago. Before I used the pucks but read about the CYA causing problems down the road so i started using bleach. I guess I'll go back to pool math and redo my calculations.

 

[Texas Splash]

I agree. I think you're right on the verge of an algae bloom. Most of us who have non-SWG pools test FC and feed our pool everyday. Just like a pet, it needs that attention. My 18K eats about 1/2 gallon of 8.25% each evening. Eventually you'll get in a routine as well. But for now ...... SLAM! (link below). Don't forget to lower pH to about 7.2 before starting.

I'm going to my local pool store to try and get a more accurate reading

I wouldn't bother. IT will only confuse yoru process. You have a terrific test kit, now you just need to get more comfortable with that CYA test. You'll get it. We'll help. Good luck!

 

[tenyc424]

so according to the pool math I need to get my FC to 28 which equals almost 11 gallons of bleach at 8.25% to slam is there another of way of doing this? or a product you recommend. My pool stores here only carry the packaged shock packs which I assume would add more cya and my cya seems on the high side as it is between 70-80. Also if your adding 1/2 gal every night that means I have to add about 1 gal every night considering my pool holds about 33000 gallons. That seems like a lot of bleach. Now I'm not sure how to approach this.

 

[Texas Splash]

We almost always use regular liquid bleach for a SLAM to increase the FC level. Based on your elevated CYA, it's totally safe. Initially you can increase FC to 28 based on the CYA of 70. I you learn later that a CYA of 80 is closer, then increase FC to 31 at that time. But it's fine. In fact, you can still swim and/or get in the water to scrub/clean any hard to reach areas. Not a problem. For the bleach (aka liquid chlorine, liquid shock) just shop around. The bleach can be generic, just make sure it is NOT splashless or contain any scents. Remember that once you initially increase FC, it may try to drop rather quickly the first day or so which will require more frequent testing to maintain the FC.

 

[Husky25]

I didn't notice if you have a SWG. A CYA of 70-80 is a bit elevated unless you do. You may need a partial drain and refill, but yes 28 FC is your target.

There is a 2016 Bleach prices thread on this forum that is helpful in finding if someone has found inexpensive prices in your area (I'd link it but I'm on my phone as I feed and put my 6 month old back to sleep). How close are you to an Ocean State Job Lot?

 

[tenyc424]

I don't have a SWG the CYA is probably elevated because I shocked my pool a few times to get rid of algae using the chlorine granules per recommendation of my local pool store. This was before I read up on CYA. As for Ocean State, nearest one is about 40 mins away.