Help with chemicals

[Johnsbd]

Haven't been able to get my pH down or get my chlorine stable. Here are my last few test results (k2006) and what I did.

8-9-16
FC - 4.5
pH - 7.8
TA - 150
CYA - 40
added 44oz MA

8-13-16
FC - 3
pH - 7.8
added 37 oz MA
41 oz liquid chlorine

8-15-16
added 96 oz liquid chlorine based on zero reading on strip test - couldn't test full and wanted to swim later in day
Full test later same day
FC - 2.5
pH - 7.9
TA - 125
CYA - 40
CC - .5 (nothing consuming my chlorine)
pool math says to add 51 oz chlorine and 41 oz MA

I haven't added either yet tonight. Am I doing something incorrect or does it take several times to get pH down? Also it seems like my chlorine should be more stable.

Betsy

 

[Jimrahbe]

Betsy,

Just to make sure we are both on the same page, you do realize that some chlorine gets used up every day. It will never be "stable". It also appears to me that you are letting your FC fall below the minimum level for your CYA. The very minimum is 3 and you really should be trying to keep your chlorine at about 5 or more.

As far as pH.. Tell us a little more about your pool. I assume you do not have a SWG. Do you have any water features, bubblers, waterfalls, etc?


Thanks,

Jim R.

 

[Johnsbd]

Yes, I do understand that some of it will get used up. Just didn't think I'd be adding as much as I have been. Especially today. 96oz and then a few hours later another 51 oz. but, maybe that's not too unusual. Was also a fairly mild day as far as heat.

I've been targeting 5 for FC. I'm not able to check it at the same time every day, so that might be a factor. Is there a good habit to get into for each day?

No SWG and no water features. Just the standard 2 jets.

Thanks!

- - - Updated - - -

I've been trying to get the pH to drop to 7.2 to get the TA down then I was going to aerate to get the pH back up, but I haven't gotten it down yet.

 

[max2k]

Yes, I do understand that some of it will get used up. Just didn't think I'd be adding as much as I have been. Especially today. 96oz and then a few hours later another 51 oz. but, maybe that's not too unusual. Was also a fairly mild day as far as heat.

I've been targeting 5 for FC. I'm not able to check it at the same time every day, so that might be a factor. Is there a good habit to get into for each day?

No SWG and no water features. Just the standard 2 jets.

Thanks!

- - - Updated - - -

I've been trying to get the pH to drop to 7.2 to get the TA down then I was going to aerate to get the pH back up, but I haven't gotten it down yet.

According to PoolMath 51 oz of 8.25% bleach for your pool size is equivalent to 2 ppm FC. This is normal daily loss to the Sun so you should expect to add that much daily. This loss is typical to the mid summer hottest days, it drops sharply with temperature decrease.
If you're losing more then it could be due to starting algae growth. I'd try to measure overnight FC loss (when the Sun is out) to see if the pool loses FC on its own more than 1 ppm overnight. If it does SLAM would be next logical thing to do.

 

[JesseSchmidt]

What test are you using to check your chlorine content? You probably should use the FAS-DPD(powder that turns water pink and drops that turn it clear) test instead of the OTO(drops that turn water yellow) test. It's more accurate counting drops to clear than judging the color of yellow against the chart. Most on here just use the OTO to check for the presence of chlorine while checking pH. Then use FAS-DPD for an actual number on FC and CC.

 

[Johnsbd]

I'm using the FAS-DPD test.

I didn't realize I needed to add so much each day. That's probably the problem. So, do I need to target a higher FC to account for the 2ppm loss each day?

I added 51 oz last night then when I got home from work today it didn't register any. Maybe I need to target a different time for adding it each day.

I'll do the overnight test tonight to see if there's any other problems. So I check it tonight once the sun goes down. Then I check it again in the morning before the sun comes up?

 

[max2k]

I'm using the FAS-DPD test.

I didn't realize I needed to add so much each day. That's probably the problem. So, do I need to target a higher FC to account for the 2ppm loss each day?

I added 51 oz last night then when I got home from work today it didn't register any. Maybe I need to target a different time for adding it each day.

I'll do the overnight test tonight to see if there's any other problems. So I check it tonight once the sun goes down. Then I check it again in the morning before the sun comes up?

you need to bring your FC up to 5 ppm first which is about 1 gal of 8.25% bleach and never let it drop below 3 ppm or you're risking algae bloom. Please do this before running overnight loss test, let it mix evenly by running pump for 1 hr before taking 'evening' FC reading. The take second FC reading tomorrow morning and post results here.

 

[Johnsbd]

Ok. So about 113 oz 10%. Thanks!

 

[Johnsbd]

Ok, here are all the results.

8-16
7pm 113 oz 10%
9pm test - 7 FC, pH 8
added 48oz (emptied bottle, could have done 52oz) MA

8-17
6:50am test - 6.5 FC (no algae issues then), pH 7.6
8:30pm test - 4.5 FC (normal loss), pH 7.6

So, based on this, do I want to add 51oz 10% each night? This targets a 7 FC, but since we typically swim late in the day, I think the math works.

 

[Johnsbd]

Anyone know if the above info looks correct?

 

[Mr Bruce]

Looks good to me

e: It's a little odd to say that you will add exactly 51 oz every day, but I think you get the main point, to add enough to get to your desired target.

 

[Griswald]

Your chlorine load will be slightly different every day, but your reasoning looks correct (as long as your CYA number is correct). If you could do 2 additions, it would work out better in the long run.

If you could do 100 small additions, that would be better still, but that would be the same as buying a SWG. That's why we have them available to us!

 

[JesseSchmidt]

Think about it this way, you test the FC every day, then put enough chlorine in to get back to your target. Use PoolMath to figure the dose you need.

Over time, you will find an average daily consumption but the weather, usage and strength of bleach(it degrades over time) all affect your level. So there is no hard fast number to say your pool will use Xppm of chlorine a day. Somewhere between 2-4ppm seems to be normal.

 

[Johnsbd]

Ok. Thanks everyone!