Order of treatment?

[Tvaughn6]

My test kit came today! My have a few levels that are off. I need to SLAM to get rid of some algae on the bottom but I need to raise my ph and TA first. Which should I do first- ph or TA?
FC 12.5
CC 0
CH 200
TA 30
CYA 70
Ph 6.8

 

[DaninFLA]

raise your pH to 7.2, then proceed with SLAM. your CYA is manageable but will require a bit more bleach. you can decide to proceed with your current CYA or lower it down to 40-50. it will work either way, just will need more bleach.

do not need to worry about TA right now, that's not too important right now.

how does the pool water look? is it green or cloudy?

 

[Tvaughn6]

Thanks for the advice. Water is crystal clear but have green spots that show up, I vacuum or brush them, and come back. This has been going on for a few weeks now... Which is what brought me to TFP

 

[DaninFLA]

ok, hopefully you have a quick SLAM then! I would try and get it done with the CYA of 70. in order to save reagent during the SLAM, you can fill the chlorine to the 5ml line and then each drop is 1ppm instead of 0.5ppm. not as accurate, but with the levels you need to be at, you are going to go thru the reagent very quick. if you are off by 1ppm or so not that big of a deal.

add a signature line with your pool info, that will help everyone. its under settings

 

[Tvaughn6]

Thanks for that tip. How long after adding the chlorine should I measure?

Also, I have a signature line but for some reason it's only showing up in my initial post. Maybe because I'm using my phone?

 

[DaninFLA]

I think there is a setting when you do the signature to show it on every post, something like that.

you can test your FC about 30 minutes after you add your bleach if the pump has been running.

 

[Tvaughn6]

When I did the FC test with 5mL of water, I got a different result. I think I'm having a hard time with half a scoop of the powder

 

[pooldv]

Use a full scoop of powder. When you type a post there is a box lower left that needs to be checked on to show your signature. It should stay checked after the first time.

 

[Tvaughn6]

Thanks. So even though I'm using half the water, still do a full scoop of powder?

 

[zea3]

Yes use a full scoop.

 

[Tvaughn6]

Thank you all for helping me as I learn all of this!

 

[DaninFLA]

if you are getting different results, then you should stick with the 10ml sample. if you can use more than a scoop, just not less.

 

[AprilsZoo]

you can use more than a scoop, just not less.

When my powder was brand new, I got a hot-pink color change with less than 1 scoop of powder-- much less, actually... The first time was when I accidentally missed the vial and dumped the powder mostly down the side & on to the speed-stir .
(Yes, I am a klutz, it's not a secret ? )...
Anyway, I asked ChemGeek (I think it was him...) and called Taylor's help line (before I trusted CG's expertise), and found out that as long as you are getting a clear pink color in the initial step of the test, then you have added enough powder... adding more won't change the result.

The short explanation was that the powder is an indicator dye that changes color when it is oxidized in the presence of chlorine... once you get the color change, the reaction is done for that stage of the test. But if you've added the 2 scoops and haven't gotten a pink change, you can be confident that you have no chlorine, because that would be enough to react no matter what.

So I stopped trying so hard to get a perfect scoop of powder, much less 2 of them.

Of course, that made me run out of R-0871 liquid way before powder... I think Taylor intended that the powder and the titrating liquid would get used up at least close to the same time, but of course it never works out that way, I'm sure. You know, now that I think about it, I still haven't needed to use two scoops, ever.

 

[DaninFLA]

well im just going off what Dave said that sells the kit always make sure to have a full scoop, and if you go over a little bit no issue. but going less can be an issue. also, if you are doing it during a SLAM with very high FC values, a little more than a level scoop may be needed.

but agree, if you throw a scoop in there and its clear, you got no FC

the initial color is also a clue as to your FC levels. if its super bright pink its very high, lighter shade is lower. that's an indicator is use during testing. I will usually just do 10 drops and swirl. if its still really dark, then 5 more. once I start seeing it lighten up, then I go one drop at a time. it definitely gets more faint as you approach your FC level before it goes clear.

 

[chem geek]

If you use too little DPD powder, then the pink/red that you see towards the end of the titration may be too weak for you to see clearly and you may underestimate the FC by one drop. This is probably more critical when using a 25 ml water sample for 0.2 ppm resolution because that end transition is not as steep. Someone did an experiment using different amounts of DPD powder and found that to get consistent results they did need to use enough powder but that any excess didn't matter.

The Taylor K-2006 instructions say "Add 2 dippers R-0870. Swirl until dissolved. If free chlorine is present, sample will turn pink." They say that regardless of whether a 10 ml or 25 ml sample size is used (which to me doesn't make sense given the differing endpoint concentrations and visibility) and by dippers they mean "level" so roughly equivalent to a "full" spoon if by full one means heaping.