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attending pool school - and have questions

I am reading and reading, and re-reading. It is starting to sink in - but I have a few questions.
1..The articles say that you shock when the CC reads a certain amount, or if the FC has been allowed to drop. Do you test the combined chlorine every time you test the chlorine? That would be nightly, right?
2.. I had to drain due to some iron and copper in my water. I didn't have any problems for 9 years, and then all of a sudden there was the staining. So, how do I make sure that when I fill (I have an auto fill) I don't have this issue again. How often should I take my water for mineral testing, or should I use a sequestrant on a regular basis because of the history?
(Currently readings for iron and copper at zero with new water.)
 
Re: attending pool school - and have questions

gemphx said:
I am reading and reading, and re-reading. It is starting to sink in - but I have a few questions.
1..The articles say that you shock when the CC reads a certain amount, or if the FC has been allowed to drop. Do you test the combined chlorine every time you test the chlorine? That would be nightly, right? No. Shock your pool when you think it needs it!! Seriously! If your pool is perfectly crystal clear and your FC consumption is normal then you may not shock all summer. When your pool looks dull or you start to notice an increase in your FC consumption, THEN you should probably run a CC's test and if it's 1.0 or more, you should probably do an OCLT. If that returns a loss of 1.0ppm or more, you can pretty much bet it is time to shock the pool.

2.. I had to drain due to some iron and copper in my water. I didn't have any problems for 9 years, and then all of a sudden there was the staining. So, how do I make sure that when I fill (I have an auto fill) I don't have this issue again. How often should I take my water for mineral testing, or should I use a sequestrant on a regular basis because of the history?
(Currently readings for iron and copper at zero with new water.)
Click to expand...
If your current water is metal free, then you have no need for a sequestrant or to even test for it UNLESS you put some in there. Never put anything containing copper in your pool. Test your fill water for iron and if it's zero, you are home free.
 
Re: attending pool school - and have questions

Thanks Dave -
(I have just ordered my test kit!)
I understand that the copper probably came from the algaecide I've used, but is there iron in some products also? I am concerned that it was in the fill water because staining happened after we filled a lot, but with an auto fill, I don't have the opportunity to test it before it ends up in the pool. (Local pool guy says iron is very rare in our water). I would feel better knowing that I inadvertently added it with something I put in there.
 
Re: attending pool school - and have questions

No, iron isn't in pool products. It has to come from fill water (test it) or something shedding iron in your circulatory system....(rusty heater pipes)
 
Re: attending pool school - and have questions

Iron can also come from lawn fertilizer spilled into the pool. Did you see little iron spots on steps and shallow areas? It is easy to use a broadcast spreader and sprinkle fertilizer+iron into the pool. Yard crews may blow the deck free of fertilizer before it gets wet and stains the deck but what gets into the pool is not their concern.
 
Re: attending pool school - and have questions

I don't have a heater, so nothing (copper or iron) coming from heater pipes.
And I don't a blade of grass in my back yard - hard to grow in the desert, it's pool and decking only, so no fertilizer.
And that scares me about the iron - cause it seems it came from the fill water. But I just refilled the entire pool and had it checked, and no iron. Guess I'll need to test for it periodically just to be sure.
 
Re: attending pool school - and have questions

cause it seems it came from the fill water. But I just refilled the entire pool and had it checked, and no iron.
Click to expand...
What can happen is you can have iron in your fill water and, when the staining occurs, that effectively precipitates the iron out of the water (and, of course on to your pool walls and floors) so when you test the pool water, there is no iron left.

Test your fill water.
 
Re: attending pool school - and have questions

The new water has no iron, not because it has precipitated, but because it just has no iron in it. We drained, cleaned and refilled and I had them test for minerals. No iron, no copper. Since I don't have any rusty heater pipes, and I don't use any fertilizer near my pool, I don't have a clue how the iron got in there. Copper was from algaecide. Would the best thing to do be to have it tested monthly, and if it shows any iron at all, then use a sequesterant?
 
Re: attending pool school - and have questions

There is almost definitely (some) iron in the water. Just because a test does not detect iron, does not mean that there is no iron. It just means that the level is below the detection capability of the test. What is the lowest level of iron that the test you had done could detect?
 
Re: attending pool school - and have questions

The test that showed iron before the drain showed the iron at 0.15. (Had some staining, but still am not positive it was iron staining) I don't know how much has to be there for the test to read.
Do I just have it tested monthly? What makes the mineral suddenly precipitate - a shock treatment? I truly do not want this to happen again and want to know how to avoid it.
 

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Re: attending pool school - and have questions

What makes the mineral suddenly precipitate - a shock treatment? I truly do not want this to happen again and want to know how to avoid it
Click to expand...
Keep your pH down in the lower 7's at all times. Metals precipitate in the presence of high pH (that's the most common cause)
 
Re: attending pool school - and have questions

gemphx said:
The test that showed iron before the drain showed the iron at 0.15.
Click to expand...
It would take 4.44 grams of iron to register on an iron test that had a lower limit of 0.10 ppm. I'm not sure how much iron is in a stain, but I would think that 4 grams could make a pretty noticeable stain.
 
Re: attending pool school - and have questions

And that is my concern - that there was sufficient iron to create a problem, but how did that much iron get there?
I just received my test kit, so I am now ready to take care of everything properly!
 
(I thought I posted this but don't see it - if this is a duplicate post, please excuse)
We completely drained and refilled so pool water is fresh.
I have been keeping chlorine in until receiving test kit, which I got yesterday.
I have added CYA slowly, last time was a week ago.
PH drifts up to 7.6 or so nightly, and I bring it down to 7.4, and then it drifts up by evening - ???
My test results with my new kit:
FC 3
PH 7.5
TA 100
CYA 42 is (I find this a bit confusing)
CH - this one really confuses me. Remember this is new water. When I did the test it turned lavender so I followed the extended directions. I'm not sure what "shade" of blue I am looking for. Seems that it went light purple and then had red particles floating and eventually went to a very, very light bluish color. I ended up with a reading of 550, following the extended directions, but that does not sound right. When I tested my tap water it read about 300 - Help!!
So, questions:
1. What makes my PH drift up and what can I do
2. What is with the Calcium hardness? Since it went to lavender and the extended directions say that shows mineral ions, do I need to use a sequestrant or be concerned? (Pool store tested no iron, no copper)
The pool actually looks really great.
 
The PH is drifting up both because your TA is a little high and because you are trying to hold the PH too low. You should let your PH go up to 7.8. The recommended range is 7.5 to 7.8. If you lower your TA a bit, say to 60 or 70, the PH should stabilize around 7.7 or 7.8.

I wouldn't worry about using sequestrant unless there is some additional sign of metals beyond the CH test.

What you described with the CH test sounds exactly like a fading endpoint. That can result in false high readings. Using a speedstir can make it easier to do the test. There isn't any particular shade of blue to watch for, just something in the blue family that doesn't change when you add another drop of titrant.
 
Thanks Dave - I will continue to post on this thread.
I have so many questions, and the more I ask and read, the more confused I get, and honestly I'm a little frustrated because just when I thought I was understanding, apparently I'm not.
First of all - to rehash very briefly, we drained and acid washed because the reading showed iron and copper and high solids, and the pool was stained. So, in my previous posts on this thread, I was advised to keep ph in the lower 7's at all times, and that would prevent any minerals from precipitating. I have been aiming at 7.4 or so, and now this latest post says I'm trying to go too low, and to keep my PH at 7.7 or 7.8. That is where I have kept my PH historically, and I ended up with scale on my tile, and stains in my pool. So, needless to say, I'm totally confused and just a little frustrated at this point.
 
Jason and Dave -
Thanks for the advice- it is greatly appreciated.
I have brought the PH to 7.4 and aerated - seems the TA has dropped a bit. I will continue this until TA is about 80. Once that happens, can I turn aeration off or will this have to be continual? What makes the TA rise?
I did my chlorine drop test last night and it dropped by .5, so I think (If I learned anything at pool school) that I do not have anything to worry about and do not have to go to shock levels. Is this correct?
I am a little concerned that I am seeing light staining again (we just acid washed!), but I have a tendency to be extremely paranoid and to expect perfection, and honestly, I am terrified that we will have an issue again. It may well be that my pool is 9 years old and we were ignorant about taking care of it.
(But just in case - is there anywhere here, or links that you can recommend that show what the different metal stains look like?)
 
Once TA comes down to a reasonable place (my last reading was 80), do I need just keep my aerator off and check TA periodically?
Learning experience : aerator really raises PH :)
 

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