Unsure about Test Methodology and a Few Other Questions

[demento]

Hi All,

I've been running my pool stuff now for a couple of weeks, and I have some questions about some of the tests.

1. When doing the CH test, it mentions to add drops until the solution turns blue. Does it actually turn blue, or is turning purple enough? I get a reading of ~200ppm by counting to 'purple', and 300ppm by counting to 'dark blue'
2. When doing the TA test, it mentions that you have to wipe the tip of the reagent bottle with a damp cloth between each drop. Why is this, and is it really necessary?
3. I have a connected pool/spa (see below). Normally, the pump sucks water from the main pool drain and there is a very tiny 'fountain' that returns in the spa. My question is, do I have enough flow and water exchange to consider these two things as a single body of water, or should I be testing both bodies independently? When I brush my spa, I'll usually force the pump to suck from only the spa and return to the pool (basically draining the spa), and then refill it by changing the return from the pool to the spa jets. This exchanges the water quite well, but I don't do this every day.
4. I'll be going away for ~4-5 days in early April. My pool currently consumes around 1Q of acid a day to hold pH in the ~7.5 range. How should I handle my going away for a few days? Can I dump a bunch of acid in before I leave and just let it get go wild for that time? Are there tabs or something else I could use?
5. My FC keeps going up. It was at 7.5ppm last time I tested, and I've got my SWG turned down to 25% (down from 50% as set by the pool builder). What % do you guys typically run at? Are there any issues with keeping FC high other than eye/skin irritation?

 

[demento]

Here's my main concern with the way the spa returns water currently. Is this really an issue or am I inventing problems for myself?

 

[duraleigh]

1. All color change tests want the change to be absolutely complete.....no further change. The actual color is not overly important.....the end of the change is.

2. There is an explanation in the extended directions. In short, you only have to do it for a couple of weeks when the reagent (R-009) is brand new.

3. I don't know

4. 1 quart daily is excessive. How old is your plaster finish?

5. Your FC consumption will increase as the warmer months get here......just keep adjusting as needed. There is no reason to put in more FC than needed. It costs money I would keep tweaking it until you learn to hold it steady around 4-6 ppm.

 

[Philo]

#5....
You need to know the CYA to determine the FC level.

To lower your FC, you could reduce your pump running time and keep the SWG at 25% or lower the SWG% if you need to keep the existing pump run time for clear water.

I have my Pentair IC-60 at 100% for 5 hours and it maintains my FC @ 6 ppm at 70 degrees full sun. My CYA is 60 ppm. As the weather warms up, I increase my pump run time. When the weather cools off, I lower the run time to a minimum of 3 hours and then lower the SWG% if it's still too much.

I'm new, so a Moderator will give you the real scoop!

 

[Richard320]

High acid consumption is common with fresh plaster. It's also common with high alkalinity fill water, which you likely have, and a lot of aeration, which your spa fountain provides, and with a SWG.

Try lowering the TA aggressively before you leave. It will come down slowly anyway as you keep pushing pH down, but aggressively working it down to 60ish should slow the pH rise enough to let you get away.

I'd also see if I could unscrew the fountain from the spa while I was gone. Then you can be sure there's at least some movement down lower in the water. It will also reduce the aeration.

If the acid demand is still high when departure day approaches, you could always shut down the SWG and get a puck floater. Trichlor pucks are very acidic. The downside in your case is that they will raise the CYA level. I don't know that you have room for it.

 

[kevbrim]

1. All color change tests want the change to be absolutely complete.....no further change. The actual color is not overly important.....the end of the change is.

Disagree with this. Purple is good. If you go all the way to the dark blue you overshot the endpoint of the titration.

 

[Richard320]

Disagree with this. Purple is good. If you go all the way to the dark blue you overshot the endpoint of the titration.

Taylor -- the manufacturer -- says you take the CH test to blue.

https://www.taylortechnologies.com/products_choose_slideshow.asp
Choose Demos of All Available Tests [updated 6/21/12] The CH test starts at 9:00

They say nothing about purple.

 

[demento]

Thanks for all the replies, guys. Richard/duraleigh, I think you guys are right. I trust the CH test more when I push to blue than purple anyway since I have a real hard time believing that my PHX tap water is only 200ppm, which is what purple would indicate. I did a test last night on the water circulation thing too. I tested the pool water, saw it was ~7.8 and put in some acid. I ran the pump for a while as I swept and kept the little fountain as I drew it in the cartoon mockup above. ~30min later, I tested both the pool water and the spa water. In both cases, I drew water from ~18" below the surface, so I was going pretty deep. They both measured right at 7.5, so I think that even with the crappy fountain stick, it's circulating OK. I'll probably pull the stick anyway just to be safe, but at least I'm relatively sure it's not as stagnant as I was fearing.