Switching from Trichlor tabs to Liquid Chlorine

[rexl23]

If no one has said yet…

Make sure you store it outside - not near any metal. The bottles vent by design and the fumes are corrosive.

Also don’t store near chlorine - the two have a chemical reaction of fumes if mixed similar to mustard gas…

Oh got it! Thank you

 

[mgtfp]

FC: 5.0 (4.8)
CC: 0.2
PH: 7.6 (7.7)
CYA: 50 (59)
TA: 80 (72)
CH: 360 (366)

PH - 7.6
CC - 0.0
TA - 90
CH - 270
FC - 3.4 (added liquid chlorine per pool calculator app to bring it closer to the high end like you suggested)
CYA - 50

That's quite a difference in your CH reading, any idea what happened there? CH is not a fast changing parameter.

You seem to be using the 25ml test for CH with 10ppm resolution. Fir CH, 25ppm resolution I'd enough, using the 10ml sample test will save you reagent.

For TA, the 25ml sample test is right.

Trichlor is not evil as such, as long as it's used in moderation and the pool owner understands the consequences. Just be aware that with every 10 ppm of FC, you are also adding about 6.5ppm of CYA. It can add up quickly.

 

[mfifield01]

If you have any tabs left, I would get your CYA up to 60 with them. I had mine around 50 with anticipation of putting tabs in for vacation. It was using a lot of LC. I came back from the vacation with a CYA of 60 and LC use has gone down. In a really sunny/hot environment more CYA is needed. I know it's not recommended, but I will probably bump up to 70.

 

[rexl23]

That's quite a difference in your CH reading, any idea what happened there? CH is not a fast changing parameter.

You seem to be using the 25ml test for CH with 10ppm resolution. Fir CH, 25ppm resolution I'd enough, using the 10ml sample test will save you reagent.

For TA, the 25ml sample test is right.

Trichlor is not evil as such, as long as it's used in moderation and the pool owner understands the consequences. Just be aware that with every 10 ppm of FC, you are also adding about 6.5ppm of CYA. It can add up quickly.

Im not totally sure why the CH changed so much.

I've seen that before though. It usually occurs after a fill though. It spikes and then goes down.

I had topped the pool a couple hours prior to the first test so maybe that's why?

 

[rexl23]

If you have any tabs left, I would get your CYA up to 60 with them. I had mine around 50 with anticipation of putting tabs in for vacation. It was using a lot of LC. I came back from the vacation with a CYA of 60 and LC use has gone down. In a really sunny/hot environment more CYA is needed. I know it's not recommended, but I will probably bump up to 70.

I'm curious to see that too. My pool gets a solid 10 hours of direct sun a day.

 

[rexl23]

Im not totally sure why the CH changed so much.

I've seen that before though. It usually occurs after a fill though. It spikes and then goes down.

I had topped the pool a couple hours prior to the first test so maybe that's why?

Just retested CH and got 327. I'm thinking I didn't math so well last night and that's the reason for the big drop.

 

[BDY]

Try using the 10 ml and reading in increments of 25

Less chance for drop variation

 

[mgtfp]

Just retested CH and got 327. I'm thinking I didn't math so well last night and that's the reason for the big drop.

The 7 is a typo, I assume? 325?

The difference to 360 I'd put down to test error, maybe slightly more then 25ml in first test and slight less than 10ml in the third test, together with the accuracy of +/- 1 drop, something like that.

I've seen that before though. It usually occurs after a fill though. It spikes and then goes down.

That's weird. It's not unusual to test lower CH after heavy rain, until the fresh rain water is properly mixed into the pool water

But to test higher after adding fill water is really unusual. That would require a CH in the fill water that's considerably higher than what's in the pool. Or something that creates a test interference.

What do you use as fill water? City water? Well water? Was the same water used to initially fill the pool?

Really curious now about CH and TA of your fill water.

 

[rexl23]

We use city water but have calcium deposits on all of our faucets that we clean off year around.

It was the same as the initial fill water.

Today my test at 6am showed 280. So there is still some fluctuation but not as much. I went back and looked at my records and each time I fill if I test the same day CH did shoot up over 300. Then 24hrs later comes back down in the mid to high 200s.

 

[mgtfp]

It would really help to see your fill water pH, CH and TA. It must have much higher CH than is currently in the pool. But then I don't understand how it got lower after using the same water for the initial fill. Unless CSI was kept very high, creating lots of scaling, taking the calcium out of the water. Or there is some calcium leaching out of the plaster each time you refill.

Where do you add the fill water to the pool?

 

[rexl23]

The builder ran a line from the outside water faucet underground to the pool. We just turn the faucet on and it fills up from a outlet in the skimmer.

I will try to get a fill water test tonight. I haven't had a chance yet.

So CH should remain relatively level?

 

[mgtfp]

Pretty much.

If you have a layer of fresh rain water sitting on top, it can test lower for a while.

I never bother to test after water (whether by rain or fill) has been added, until water has mixed.

I only test CH once in a while, and then I try to pick times when I (or nature) haven't just messed with the water. I have soft water, and CH is a very slow changing parameter. In my case very slowly creeping up in summer with fill water additions, and going down in winter with rain and overflow draining. In the yearly net, my CH is going down and I have to bump up CH from time to time (counting years, rather than months).

Each pool is different, depending on climate, shade, fill water, pool cover.

What you are seeing, I haven't seen before.

Also make sure you test consistently. Don't squeeze the dropper bottle, hold the bottle vertically and try to let the drops fall with as little squeeze as possible.

Don't bother with 25ml samples. 10ml samples give enough precision for CH.

How old are your reagents?

 

[rexl23]

Reagents are only about two months old. I store them inside where it's cool and dry.

I retested the pool this evening. CH showed 260 again. Then I tested the fill water.

Fill water showed only 110 so there goes my theory on high CH from our faucets. PH was about 6.5, TA 90, CC 0.0, and FC 0.0.

I was very careful and tested very slowly the last two times the pool CH numbers were very similar.

I'm thinking I was the anomaly and wasn't careful in counting drops or on my math. Also noticed the Waterguru is all over the place with the auto CH test. I'm not going to rely on it much. PH and FC are close enough usually it gives me a warning and then I use the Taylor kit to verify.

I'm keeping a log on the pool math app to try to recognize patterns.

 

[rexl23]

Tested again this morning. Here is what I got.

PH 7.4
FC 6.0
CC 0.2
TA 90
CH 230

 

[amymeme]

I probably won't be able to do the SWG for awhile but it is definitely on the list now after everyone's suggestions. I wish the builder would have mentioned it. Hindsight.

I'm usually only gone for work 3 - 4 days so even if I can set up a cal hypo floater for my wife to drop in the pool half way through that to keep the chlorine up and algea at bay that would be good.

Is the inline chlorinator never going to be an option for anything but Trichlor now? Like no length of time is great enough to have it cleaned out of the Trichlor tablets residue for it to be safe? Our local pool store sells slow dissolve calhypo tabs is why I am asking.

Buy several Walmart 81 oz jugs of 7.5% bleach - read the ingredients, straight sodium hypochlorite, nothing else. Figure out on pool math how much you usually need per day and she can put it in the stream of the return line. Easy. She really should know how to manage the pool as well as you, things happen. I'm a 72 year old arthritic woman and I do all the pool work. Except add acid - I'm not known for being careful and a splash or 31.45% muriatic acid is not something I want splashed in my eyes. I use a a vice grip oil filter wrench to open the chlorine carboy and a johnny pump to transfer the chlorine to an empty, cleaned milk jug (they're somewhat translucent so you can see how full the jug is). Teach her to at least test for FC. The FAS-DPD test is straightforward and instructions are clear.


Good luck with your pool and enjoy - from what I've read - Texas heat demands a pool!

 

[rexl23]

Buy several Walmart 81 oz jugs of 7.5% bleach - read the ingredients, straight sodium hypochlorite, nothing else. Figure out on pool math how much you usually need per day and she can put it in the stream of the return line. Easy. She really should know how to manage the pool as well as you, things happen. I'm a 72 year old arthritic woman and I do all the pool work. Except add acid - I'm not known for being careful and a splash or 31.45% muriatic acid is not something I want splashed in my eyes. I use a a vice grip oil filter wrench to open the chlorine carboy and a johnny pump to transfer the chlorine to an empty, cleaned milk jug (they're somewhat translucent so you can see how full the jug is). Teach her to at least test for FC. The FAS-DPD test is straightforward and instructions are clear.


Good luck with your pool and enjoy - from what I've read - Texas heat demands a pool!

Thank you very much! She is slowly starting to learn about it now. And we have been at 100+ for 21 days straight now I think. A lot.of those were 105+!