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Just Starting And Fully Confused


deld
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If I did this right, my pH is 7.6, Alk is 150, CH is 275 (city water report says average is 290). The water is warming up, it's at 67 and climbing. The tub is 290 gallons.

So I need to bring the TA down, and I understand I need to bring the pH down to do that, and then aerate. Pool Calculator just says add acid but nothing useful. I've got the starter set of Rendezvous chemicals which has a calculator on their site that says to add pH down, repeat as necessary. The pH down is 95% sodium bisulfate. The instructions on the bottle say 1.5 tsp per 500 gallons, but doesn't say anything about how much that'll bring it down.

I'm guessing about 3/4 of an ounce of pH down. So I should add about 1/2 of that, and then test again in a few hours?

Since I'm just starting this, I haven't added anything yet, including dichor. I know I need to get started on that soon.

I am just really confused.

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Usually you want your TA down in the 50's. if you go to the bottom of the pool calculator you can see what adding different chemicals will do to certain aspects of the chemistry in your tub. Adding 9.5 oz of dry acid to your tub will bring down the TA by 95 (150-95 = 55 TA as your remaining number).

You start by putting in half that amount and running the tubs with full jets for 30 minutes and then testing again to see what your TA number is. Then you recalculate ad do it again. I was new starting October of this year and have had very few problems once I read the stickies at the top of this section. You NEED to do that. The bleach / dichlor method is great. Again, first tub, but our friends have had one for years and cannot get over how clear our water is. I do check it every day. I have test strips but they are pointless. I use the Taylor 2006 FAS kit daily to check my tub. I like to stay on top of my numbers.

It seems difficult at first. A small kitchen scale will help. The dry acid is by weight.

Happy tubbing!

Scott

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I had the stickies open and was still confused. 2 things that would have been great to see in the stickies are 1) get a small kitchen scale if you don't already have one, and 2) what dry acid actually is. Eventually I found that what I have is what everyone's talking about when they say dry acid, but I didn't see it anywhere in the stickies, and that was contributing to my confusion.

I've got a scale ordered, it'll be here tomorrow. In the mean time I'm using a glass measure and going with estimating how much I'm pouring out of the bottle based the level left in the bottle. It's not the most exact, so I'm inching my way down. I'm down to TA of 120 with my pH at 7.6 My Cl was 3. something this morning when I was checking things. When I was home for lunch at 4, I used a test strip because it was fast, and they are really not as specific as the drop tests. You guys are so not joking about that. But, knowing what the levels were this morning, it was good enough to tell me that I needed to add more dichlor. I added the same amount I did yesterday, so that should get me to tomorrow evening and I'll add more.

And then there's the other strange thing. My manual says pH 7.4 to 7.6, and TA of 125-150ppm. And that last part is odd compared to everything I've seen. The advice everywhere is much lower.

My goal for the weekend is to get this all set. The other problem I keep running into is the lack of daylight. We're fully dark by 5 pm, so I'm scrambling for daylight to read tests.

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I'm 7 miles from the eastern edge of the time zone. Dark is just crazy early in the winter.

I was wondering about lights for reading the tests. The drop test and the strips both say read in natural sunlight, and I was wondering how important that was.

On the plus side, I think I'm getting the pool calculator figured out. I spent the morning adding acid, and more acid, and more acid and then borax, and more acid. But I've got the TA down to 60-70ish, and the pH is 7.4, at 100 degrees with 275 CH. That should be about right. The TA could come down a little, but I'll do that tomorrow when I test everything again. I just added dichlor to get to 10 ppm and I'm going to leave it alone for 24 hours to get the Cl demand.

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I'm 7 miles from the eastern edge of the time zone.  Dark is just crazy early in the winter.

I was wondering about lights for reading the tests.  The drop test and the strips both say read in natural sunlight, and I was wondering how important that was.

I had the same problem. We use our tub exclusively in the evening, and this time of year it is often dark before I even get home from work. In the demo videos at the Taylor website they are using something they refer to as a "daylight simulator." Googling this produced nothing, but I could see the brand name ("Gepe") so I did more searching and discovered that this is actually a slide viewer. Being a hardcore gadget freak, I had to have one. I found that there are two sizes suitable for viewing drop tests, 4x6 and 5x7 inches, which are the model 802001 and 802002 respectively. I got lucky and found a 5x7 model at a good price on eBay. B&H Photo (bhphotovideo.com) also carries them.It works perfectly. Now I can accurately check pH, FC, etc., day or night.If you want one I wouldn't wait too long to start looking, since slides (and film photography in general) are rapidly going the way of the VCR.

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When I left off yesterday, I was at TA between 60-70, and the pH was 7.4, at 100 degrees with 275 CH, and I'd just added dichlor to go up to 10 ppm for the Chlorine Demand test. - Does that need to be done with each water change? I assume so, because of differences in the water supply, but maybe those changes are too small to matter.

Anyway, right at 24 hours later, my free Cl is down to 5.8 giving me a CD of 4.2. I've also got .4 Combined Chlorine. My pH is up to 7.8, TA at 70. I think I'll try a smidge of acid and test, and then after I soak test again to see if the jets changed the pH.

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The reason for the higher TA recommendation you see in the spa industry is that they assume you will be using a net acidic source of chlorine such as Dichlor or a net acidic non-chlorine shock such as MPS. However, if you use the Dichlor-then-bleach method, you want the TA low since the bleach is closer to being net pH neutral and a higher TA will result in faster carbon dioxide outgassing that would raise the pH.

As for chlorine demand, you can't test that right after you soak. You can only test for the background chlorine demand at least 24 hours after a soak assuming you didn't use up all the chlorine (i.e. that you used enough chlorine after the soak and after 24 hours you then raise the FC to do the chlorine demand test). You shouldn't need to test for the background chlorine demand after each refill -- the tub should be in good shape once you get it in that good shape.

You had a 42% 24-hour chlorine loss. Assuming you did that properly and didn't start the test too soon after a soak, then that's on the high side unless you have an ozonator. Do you have an ozonator?

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No ozonator.

Saturday morning, I worked on lowering the TA, keeping the pH in line and adding borax, then not immediately, but shortly after I added dichlor to get to 10. I left the tub entirely alone for 24 hours and then tested the FC. I can do another 24 hour test this weekend and see how that goes.

I tested FC 15-20 minutes after I got out of the tub last night, somewhere between 9 and 9:30,and added dichlor to get to 6 ppm. Tonight, a little after I got out, about 8, I tested and it was 2.8 ppm. Which implies my weekend test was wonky. I added .1 oz of dichlor. This should be me at 27 CYA, so I'll switch to bleach tomorrow. A few minutes after I added that, I tested pH which was 7.8 and then the TA was about 50. I left those alone tonight, and I'll see how stable they are tomorrow.

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Yeah, I wouldn't worry too much about a single wacky test.  It sounds like things may be in good shape.  Just keep testing and if things are stable and you get to "know your tub" and your usage and chlorine demand, then you can back off the testing a bit.  Usually once things are stable, they stay that way and only slowly change over weeks.  Eventually, the buildup of slow-to-oxidize and unoxidizable organics has the chlorine demand rise and the water get dull/cloudy which then requires a water change, but with the Dichlor-then-bleach method you can usually go at least twice as long as compared to Dichlor-only. Don't forget to add some more CYA about once a month by using Dichlor for a day or so; the CYA slowly oxidizes in spas at a rate of around 5 ppm per month.

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tonight, after 24 hours and a 45 minute soak my Cl was 1, so I added 3 ounces of bleach. My pH was about 8 and TA was still at 50. I didn't add anything else tonight. I'm probably not going to be in tomorrow, but I'll test tomorrow night and see what happens. I'm hoping I can get to the daylight of the weekend before I have to fiddle with pH and TA.

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