Where is my chlorine going?

[BackyardAquamarine]

We just purchased this pool secondhand and it's my first week trying to get it up and running, and I am kind of stuck. I have a TF-100 testing kit on its way, but it's not here until Wednesday, so I'm trying to make due with the test strips I got from the store.

H: 0
TC:0
FC: 0
pH:7.2
TA: 120
CYA: 0

I filled the pool and successfully adjusted the pH and TA using The Pool Calculator. My next step was to raise the chlorine to 4, then add the CYA (per the instructions on the CYA, which say to raise chlorine before adding). So, one evening, I added 3c of 6% bleach per The Pool Calculator and ran the pump. When I tested in the morning, the chlorine was 0 or maybe 1 (slight tint to that part of the test strip). I tried the same thing on 2 other nights, this time testing 2 hours after putting it in and again the next morning...same result.

I understand that without CYA, the chlorine will break down quickly in the sun. But I didn't expect it to happen in the night. And both TC and FC are at 0; neither one seems to move.

Any ideas what I'm doing wrong?

Thanks!

 

[Texas Splash]

Hello and welcome to TFP! Yes, without CYA, the FC is getting tore-up by the sun. No doubt. Using the calculator, you'll want a beginning summer CYA of about 40. Increase FC to about 2-3 on day 1 (today). Tomorrow increase the FC to about 5-7 and never let it drop below 3.

To increase CYA via granular stabilizer, place the required amount as calculated by the Poolmath calculator into a white sock and place in the poolside skimmer basket. For those concerned about suction flow to the pump, suspending the sock near a return jet or from a floating device will also suffice. Best never to allow undissolved granules to rest directly against the pool surface. Squeeze the sock periodically to help it dissipate. Once dissolved, consider your CYA adjusted to that programmed (target) level. CYA test readings should show a rise in 24-48 hours, however some pools may experience a longer delay to fully register. Best to confirm final CYA in about 5-7 days before adding any more stabilizer/conditioner.

Hope that helps get you going.

 

[BackyardAquamarine]

Thanks for the quick reply! Just so I'm sure I understand, I can add the CYA while I am bringing the chlorine level up? The label on the CYA makes it sounds like they have to be done in order.

Also, would not having CYA in the pool cause the chlorine to go away at night, too? That's the part that is confusing me. I thought CYA only mattered during the day.

 

[Mike1162]

Is the water clear or cloudy?
Any sign of algae?

 

[BackyardAquamarine]

Is the water clear or cloudy?
Any sign of algae?

Completely clear and no sign of algae that I can tell.

 

[lightmaster]

so I'm trying to make due with the test strips I got from the store.

Just a heads up, I had some Clorox test strips, and did 3 tests back to back, and got 3 significantly different results. Also, what their app said and the colors I saw didn't match up at all. Ended up making my pool very cloudy and full of algae. Ended up draining and refilling it entirely and got a TF-100 test kit in the process.

 

[Mike1162]

You're probably on the verge of an algae break out & that's consuming the chlorine. The TF-100 will show this as CC. A remote possibility is that the chlorine is very high & bleaching the test strips.

 

[BackyardAquamarine]

You're probably on the verge of an algae break out & that's consuming the chlorine. The TF-100 will show this as CC.

What is is the best want to intervene with the tools on hand? I read the SLAM procedure but I can't seem to do that without the TF-100 kit. But waiting two days seems like not the best idea.

A remote possibility is that the chlorine is very high & bleaching the test strips.

The other colors on the test strip are vibrant so I think (hope) it's not that high. I may make a concentrated test solution from tap water just to make sure the strips are working.

 

[Mike1162]

Sorry for the delay. I had to run to Walmart for chlorine. Add a quart of bleach, let it circulate for 30 minutes & check with your strips. Let's shoot for 5ppm. Will the test strips go that high?

 

[BackyardAquamarine]

Yes, they go to 10. I'll run down the street and grab some now.

 

[Texas Splash]

I agree. Until the TF-100 arrives, try to keep everything simple and don't get too far ahead of things. Add a small amount of bleach each day, or perhaps once in the morning and once at night, just to ensure you have a small amount of FC recording - a good 3ppm or so is better than nothing right now. Do the best you can is all for now. Once the kit arrives, we'll help show you how to get very precise with your dosages. In the meantime, make sure to read the SLAM page, and spend some time getting your eyes used to the Poolmath Calculator. It can a little overwhelming to see at first, but once you get the hang of it, you'll see how valuable it is. Have a nice evening.

 

[AimeeH]

Thanks for the quick reply! Just so I'm sure I understand, I can add the CYA while I am bringing the chlorine level up? The label on the CYA makes it sounds like they have to be done in order.

Also, would not having CYA in the pool cause the chlorine to go away at night, too? That's the part that is confusing me. I thought CYA only mattered during the day.

Two things cause your chlorine to be consumed organics and sunlight. Organics can be things like algae or even just bacteria carried on our bodies when we get in the pool. CYA is like sunscreen to protect the chlorine from being burned off too quickly by sunlight. Chlorine does not get consumed by sunlight during nighttime hours....only organics can cause it to be consumed at night. Which is the nature of doing an overnight chlorine loss test as part of confirming you've cleared up algae when necessary.

I hope that helps

 

[BackyardAquamarine]

Thanks for the suggestion, BTW. It's busy circulating, I'll check on it here shortly. I also created a sample solution just from tap water to make sure that the strips were changing and was able to confirm that they are.

 

[BackyardAquamarine]

After 30 min, the TC is 5 and the FC is somewhere between 3 and 5 (the strips are a little hard to read). This seems like good news to me, yes?

I will check it again first thing in the morning.

 

[Mike1162]

If you're going to be up for a while then you could check it again in an hour. In an hour or in the morning keep adding enough chlorine to keep the TC around 5.

 

[BackyardAquamarine]

I added one more cup of bleach around midnight; when I checked this morning (about an hour after sunrise) it TF and CF were still in the 3-5 range. So I find that encouraging.

Thank you so much for all the help!


I will work on bringing the CYA up today. It looks like I want to have that in the 70 range to turn on the SWG.

 

[Mike1162]

Don't go to CYA 70 until you get the TF-100 so you have an accurate value to start with.
Did you already get a SWG?

 

[BackyardAquamarine]

We got it second hand and it came with one, so I figured I would set it up. Although I can run it with just chlorine if you think that's a better idea.

 

[BackyardAquamarine]

Should I aim for 40 then?

 

[Mike1162]

You can set it up but let's just target CYA of 30. Once the TF-100 arrives we'll determine if you need to do the SLAM procedure which takes less chlorine with CYA at 30.