Confusing Test Results

[Oakstone]

Heya,

When I filled the pool yesterday, I had the following results:

FC - 0.5
PH - 8.0
TA - 30
CH - 30

Using the app, I was instructed to add:

661ml 6% bleach
87ml 31.25% (20 baume) Muriatic Acid
2200gr Baking Soda
2100gr Calcium Chloride

I didn't have the full amounts of the Baking Soda and Salt, so I added 1000gr of each, figuring it was to raise those levels anyway and I could top up after a test today.

So, this morning (15 hrs later), my results were:

FC - 0.5 (added another 661ml bleach)
PH - 7.4 (yay)
TA - 190 (uh oh)
CH - 20

According to the app, I needed to lower my PH via Muriatic Acid and raise it via aeration. So, I've added 125ml (ran out of the bottle, suggestion was 237ml) and I now have the aerator running.

App also said to add another 2797gr of Calcium Chloride.

I guess I just want to know why my TA went so high, even though I only added 1/2 the amount of baking soda it asked me to. I used Kosher Salt for the Calcium Choride after reading about it being perfectly fine, especially with our pretty pure salt in Canada. Was that a mistake?

Thoughts? Is this "Swing" normal in the TA as I get it all settled out?

Thanks!

 

[jblizzle]

Do you have your pool volume set to 1100 or 11000?

Also note that the app does not tell you what to add. It calculates what would be required to reach the target levels you set. It is up to you to understand what levels you want to reach and what needs to be added to do it.

There is no reason to CH to your vinyl pool. And TA is just about the last thing to be concerned about.

 

[setsailsoon]

Oak,

Hi, can you add a little more information? What FC level are you shooting for? I'd recommend you read through Pool School or at least the beginner's link below. You need to know your CYA level to determine the required FC. I show the amount of 6% bleach you added would increase the FC by 9.8 ppm. As Jason indicates above you need to be focused on FC and pH first. Something is chewing up your chlorine. Typically either algae or ammonia. What test kit are you using? Please see the recommendations for kits in Pool School. The Taylor K2006c or TF 100 both have capability to test for everything you need to balance a pool using TFP method.

I hope this helps and good luck!

Chris

 

[Oakstone]

Thanks for the replies! Soooo turns out that the app (not the first time) reverted my 4300L to 4300 gallons. Ffs. I have to keep an eye on that. Definitely a bug.

I haven’t tested CYA since it’s a new fill and I had two other folks say to just test everything else, which I did.

Looks like the TA isn’t too much of a concern. With the fresh fill (targeting 3.0 FC) I could see it eating some for whatever is in the tap water.

Hopefully now with the correct volume I can stabilize things.

I will do CYA if you think it’s necessary but with the kit only having 2 tests I’d like to only do it when required. It’s a non-C kit so fewer reagents.

 

[jblizzle]

I contacted the admin about your PoolMath issue. Are you sure you have the latest version of the app? At one point there was an issue similar to what happened to you, but it has been corrected.

 

[Oakstone]

Thanks for that! I did just reinstall it the other day. I’d assume the version from the iTunes Store would be up to date.

 

[Oakstone]

Oh, for the bug report, it was still in litres but looked like the conversion of 4300 glass worth, so like 16K litres. So it didn’t change 4300 L to G in the display. It’s like it converted it as though I had entered 4300 G and then changed the units.

 

[Chickinvic]

Victoria, BC was my hometown. Lived there until 2013 (I'm in Ottawa now).

 

[setsailsoon]

Thanks for the replies! Soooo turns out that the app (not the first time) reverted my 4300L to 4300 gallons. Ffs. I have to keep an eye on that. Definitely a bug.

I haven’t tested CYA since it’s a new fill and I had two other folks say to just test everything else, which I did.

Looks like the TA isn’t too much of a concern. With the fresh fill (targeting 3.0 FC) I could see it eating some for whatever is in the tap water.

Hopefully now with the correct volume I can stabilize things.

I will do CYA if you think it’s necessary but with the kit only having 2 tests I’d like to only do it when required. It’s a non-C kit so fewer reagents.

Oak,

I missed the new fill so you're right it's sort of a waste to test it now as there is none in fill water. Good idea to conserve reagents for later. Sorry for the error on my part.

Chris

 

[Oakstone]

@setsailsoon Something is definitely eating my chlorine! It's back to 0 from the bleach addition I did yesterday. So weird. When I set up the pool (it was dried and stored in my shed), I used some water and bleach with a brush to scrub out the bottom and sides of the interior. I then shop vac'd out the bottom until there was as little as possible left (less than a liter of water I'd guess). Then I filled, tested and balanced, which ended up with more bleach than I should have due to the app error, so the FC would have been pretty high afterwards.

Today's test results:

FC - 0
Combined Chlorine - 0
PH - 7.6
TA - 200
Didn't bother with Calcium Hardness

So, what do I do now? What could be eating my chlorine after less than 36 hours of operation?

Thanks for any insight you have!

 

[jblizzle]

What is your CYA?
What time did you add the chlorine yesterday?

 

[Oakstone]

@jblizzle I haven't tested CYA yet because it was a fresh fill the day before yesterday. Everyone's been saying not to test it so I don't waste my reagents.

I added the chlorine mid-morning yesterday.

 

[Mr Bruce]

That's where your chlorine went. Without CYA it'll all be gone in a day. You need to add 30ppm to the pool. It's available at WalMart, Lowes, Home Depot, etc as "Stabilizer" Check for 100% CYA, nothing "blue".

 

[jblizzle]

The sun destroyed all your chlorine. About 1/2 the FC will be destroyed by the sun every hour. So after just a few hours the FC will basically all be gone.

 

[Oakstone]

Gotcha ok! I realize I misinterpreted "don't test CYA" with "don't do anything about CYA", so I didn't add any stabilizer. I have some and have added the recommended 129g into my skimmer. Test CYA in about 3 days then?

In between now and my CYA test, I assume I just check levels as normal and make any adjustments that pool math suggests?

Thanks for the patience! Slowly learning haha.

 

[an1vrsy]

Oakstone, are you using the sock method for adding the granular stabilizer? You can periodically go our and squeeze the sock to help it dissolve.

 

[Mr Bruce]

Next time just put it in a knee high and either
-Suspend it in front of a return
-Put it in the skimmer
-massage it in the water

If you just dump it in the skimmer you'll lose it all if you have to backwash.

 

[jblizzle]

If you just dump it in the skimmer you'll lose it all if you have to backwash.

And it is much slower to dissolve if sitting in the filter.

 

[Oakstone]

Ruh oh! I read about the sock, but then also read to just put it into the skimmer and let it dissolve in the filter. I don't backwash, my pump doesn't do that, so I usually just take the filter out and hose it out when needed every several days, then replace once a month or so. I'll just not remove the filter for a few days at least. Should be ok?

 

[jblizzle]

FYI, you can get better aftermarket cartridges for the Intex filters that are fully reusable ... Unicel makes them. That gives a fair improvement to the filtration. Upgrading to the sand filter is a better, although more costly improvement.