Fill water on well source - CH question

[wgipe]

Ok....so the new pool will be ready to be filled next week. My question is this: I see that target CH for a vinyl liner pool is on the 40 range. I got a TFT100 test kit and some salt strips, and tested my well water before it hits any treatment systems (we have an ozone system followed by a softener). Here are the results of those tests:

Fill water from well
CH: 200ppm
TA: 270
pH: 7.8
Total chlorine: 0 (as assumed, tested anyway)
Salt: 0 (also as assumed, but tested)

The way I’ve run my fill line, I can easily connect the line to either hard or soft water. I also thought about putting a three-way valve where it is tapped in the house so I could switch between the two.

my questions:

- what would you do?
- given that my fill water CH before the softener is so much higher than target, should I only do soft water? The 40 CH target is much lower than my salt cell manual calls for - is that ok?
- if I don’t have a soft water fill option, would t my CH just continue to creep up over time, leaving me no way to bring it down?

Sorry for the rookie questions - just getting started, so all this is new to me.

Thanks!

Wes

 

[mknauss]

I would use the pre softener water. 200 ppm CH will be of no issue. I suspect that refill due to splash out, evaporation, etc will be via rain water for the most part.
Recommended Levels

 

[wgipe]

I would use the pre softener water. 200 ppm CH will be of no issue. I suspect that refill due to splash out, evaporation, etc will be via rain water for the most part.
Recommended Levels

That calculator is really cool - I hadn't yet seen it. Not sure where I got my 40 number, so it looks like I'm good there. With my TA being 270, it looks like I should lower pH, then aerate and repeat as often as needed to get TA in line. Is the 270 number going to cause problems until I get it under control?

 

[mknauss]

The TA will not cause an immediate issue. The pH will rise quickly. I assume you are closing the pool for winter. You should try to get the TA lower as the pH will quite high with that level of TA over winter.

 

[wgipe]

The TA will not cause an immediate issue. The pH will rise quickly. I assume you are closing the pool for winter. You should try to get the TA lower as the pH will quite high with that level of TA over winter.

Thanks - yes. We will close it as soon as I can get the water where it needs to be. I am nearly certain that they will be filling from a truck, so what that water looks like remains to be seen. I am pretty nervous about just balancing and closing right away - I would hate to do something that would hurt the liner over winter. Everything else will obviously be winterized, so mainly concerned about the auto cover and the liner. A few questions, if I may:

1.) Would it then stand to reason that I should shoot for the minimum acceptable pH (7.2 per the link above) so it has some room to rise?
2.) Given that I'm closing in a hurry, should I test a few times through the winter to make sure pH doesn't get out of range?
3.) I have liquid chlorine to get started. Given that we are clear at the end of the season and it is very unlikely water temps will allow the IC40 to produce, should I just leave the dummy cell in and install in when I open?
4.) Am I overthinking this? I have a habit of doing that...

Thanks for your patience.

Wes

 

[wgipe]

One other question - I had my water tested by a lab in June due to installing a new water treatment system which showed our iron levels at 0.035 mg/L. I've seen a few posts where @duraleigh has warned against filling from a well because of iron. Is this enough to be concerned? I can post the full analytics report if it would help.

Thanks,

Wes

 

[mknauss]

Have your pH in the 7’s when you close

As it is unlikely you can properly mix in a chemical once closed, no real need to test

Close with your FC at 10 ppm.

Sounds like really low iron. But watch for any color change to the water when you add the chlorine.

 

[wgipe]

Have your pH in the 7’s when you close

As it is unlikely you can properly mix in a chemical once closed, no real need to test

Close with your FC at 10 ppm.

Sounds like really low iron. But watch for any color change to the water when you add the chlorine.

Wonderful. Thank you. From what I'm reading, it would appear that I don't need to worry about CYA (will be zero on fill if I'm understanding correctly) until I open the pool. Is that correct?

 

[mknauss]

Essentially. Just do not go over 10 ppm FC.

 

[duraleigh]

Don't listen to that Duraleigh guy.......he can get pretty cranky.

So, generally, I think you have an EXCELLENT grasp of your chemistry. So let me answer your questions

1.) Would it then stand to reason that I should shoot for the minimum acceptable pH (7.2 per the link above) so it has some room to rise? perhaps not necessary but I like that idea. pH will tend to rise with lower water temps so it will never hurt to start out low
2.) Given that I'm closing in a hurry, should I test a few times through the winter to make sure pH doesn't get out of range? Testing is the basic premise of what we teach. It is reassuring to know you are "in the zone" in the winter
3.) I have liquid chlorine to get started. Given that we are clear at the end of the season and it is very unlikely water temps will allow the IC40 to produce, should I just leave the dummy cell in and install in when I open? Absolutely. I would carry it a step further and manually chlorinate when you open (below 60 degrees water temp) then get your SWG tuned in to maintain your FC......not bring it (FC) up from zero
4.) Am I overthinking this? I have a habit of doing that... I don't think so (and I get cranky with those who do). I believe your ideas and your comprehension of the chemistry is really good......you are well on your way to becoming a pool nerd like the rest of us.

Yes, your CYA will be zero until you put some in next Spring, and yes your iron content is just fine as mknauss says.

 

[wgipe]

you are well on your way to becoming a pool nerd like the rest of us.

Well that's the nicest thing someone's said about me all week.

If I do the above, it looks like Polyquat 60 is not necessary. That said, if it's cheap insurance, I would happily do it. Advice on that?

Sorry for all the basic questions - I really hope I can return the favor once I have this all figured out.

 

[ajw22]

PQ60 should not be necessary with new clean water and some chlorine in it. But PQ60 is an insurance policy against a green opening if you get nasty runoff into the pool during the winter.

 

[wgipe]

PQ60 should not be necessary with new clean water and some chlorine in it. But PQ60 is an insurance policy against a green opening if you get nasty runoff into the pool during the winter.

Thanks. It is in the back yard outside a walk-out basement and everything does slope toward that area. They shot everything with a laser and have raised the pool such that I’d be really surprised if we end up with anything going into the pool. We’ve also got a channel drain between the pool and the house with fall both ways just in case.

If it will cause no harm, I think I’ll just do it so I can sleep if we do get some runoff for some reason.

Thanks again guys - I am so grateful for all the advice.