Test results and goals

[stevodevo]

Hi all,

Here are my latest test results and also my goals for where I'd like them to be. I'd love to hear from the gurus to make sure I'm on the right track.

FC - 4 (generally sitting between 3-4)
CC - 0
pH - 7.5
TA - 60
CH - 280
CYA - 35
Clarity... like bottled water!

I'd like to get my CH up to 350 and CYA up to 70 and leave everything else as is. I'll probably try to target FC at more like the 4-5 range. My pool is still only just over 3 months old so pH is going up constantly but I'm hoping that getting my TA down to 60ppm finally will help a bit (or is it just a lost cause with pH for the first year?). I'm not planning on adding borates at this stage. I understand that with a SWG my pH will always drift up, but I'm hoping at least after the first year it slows down a bit. So goal levels would be:

FC - 5
CC - 0
pH - 7.5
TA - 60
CH - 350
CYA - 70

Pool Calc puts my goal levels at a CSI of -0.48 which seems pretty close to -0.6 (at a pH of 7.4 it goes down to -0.57!). As my pH drifts up to 7.8 the CSI goes down to -0.21 so I'm figuring I'll always be heading in the right direction? Is that the correct way of looking at it or should I be looking to increase my TA a bit? Increasing TA to 70 would have me sitting on -0.38 which seems safer, so I guess the question is whether staying at 60 will help control pH drift enough to compensate for the borderline CSI. I've only just got it down to 60 with current rainfall so it's to soon to for me to tell from here.

I've been running my pump on eco speed, with SWG running between 40-50% for 10 hours a day (7:30am-3:30pm then 8:00pm-10:00pm), but after next weekend I'm going to start reducing that to see if it helps my rising pH.

Thoughts?


Thanks,
Steve.

 

[duraleigh]

Hey, Steve,

I don't know if there is a TA test that has a precision better than plus or minus 10 so attempting to change TA by 10ppm is a moot point.

I guess you are moving CH up because of something to do with csi which I have never used. I see no reason to change CH.....it's virtually perfect.

Last, the appearance of your water is perfect and your chemistry is virtually perfect as well. Here in North Carolina, that usually means, "Don't fix it if it ain't broke!" :-D

 

[stevodevo]

Hi Dave,

Thanks for the reply. I am still tempted to just leave things as is but I suppose I'm new to all this and so I'm not sure how much weight to place on CSI. My reasoning for increasing CH is because at 280ppm, Pool Calc returns a result of -0.57 which if reliable would have a noob like me thinking there's some unseen reaction (even though my water looks perfect) going on in my water that's SLOWLY reducing the life of my plaster. I'm trying to subscribe to the theory rather than use my own inexperience as a guide.

Interestingly, this raises another question I was getting around to asking... the "Watergram" that comes with the Taylor kit puts CSI at about -0.1 with my current levels. Oh by the way, water temp is averaging around 28-30C depending on the weather. That's a big difference, but as I write this, I'm playing around with both and have just noticed for the first time that a salt level of 4000ppm "decreases" the CSI on pool calc by about 0.25 so considering the Taylor Watergram doesn't take into account salt levels that would explain much of the difference. Actually, CYA isn't on the Watergram either and when I take both salt and CYA out of Pool Calc they are pretty much dead on the same -0.12 at 28 degrees.

So should I care that my current CSI on Pool Calc is REALLY close to what it suggests could cause problems or should I take the more lenient approach of the Watergram.


Thanks,
Steve.

 

[duraleigh]

Well, that gives me just the opening I need to get back up on my soapbox and start preaching again.

This BBB method of poolcare was worked out long ago without ANY consultation to csi or the watergram. I personally have never used either and my pool is as clear and troublefree as anyone's here on the forum (unless I get slack with the chlorine in August )

BBB is all about YOU understanding what you are testing, why you are testing for it, what are the acceptable ranges and, importantly, what to do if you start to drift outside those ranges.

We have had more than one person come on the forum with a slime pool, get the csi to come into acceptable range and then post back saying their slimey green pool and frogs are still there....what happened? Obviously, they are relying on a method that they don't understand and the whole principle of BBB is understanding.

So, I would suggest you use neither csi or watergram (that said, there are good people here who will disagree with me.......their pools won't be any more sparkling, but they will disagree) and that you test and monitor you pool carefully at first, particularly pH because of the SWG, and that in the very new future, you will know and understand the rhythm of your pool and will only have to test some to make sure you are staying within parameters. In other words, this gets easier and easier and I hope you don't get so bogged down in the minutiae, that you overlook how important your own judgement and knowledge will be in your pool's care. :lol:

 

[RaviePoolGirl]

Dave, I am so glad that you said that because I too felt like getting my pool to the "Perfect" water parameter with the CSI was placing my pool at risk for plaster damage!

 

[chem geek]

Interestingly, this raises another question I was getting around to asking... the "Watergram" that comes with the Taylor kit puts CSI at about -0.1 with my current levels. Oh by the way, water temp is averaging around 28-30C depending on the weather. That's a big difference, but as I write this, I'm playing around with both and have just noticed for the first time that a salt level of 4000ppm "decreases" the CSI on pool calc by about 0.25 so considering the Taylor Watergram doesn't take into account salt levels that would explain much of the difference. Actually, CYA isn't on the Watergram either and when I take both salt and CYA out of Pool Calc they are pretty much dead on the same -0.12 at 28 degrees.

As you figured out, the Taylor watergram does not take into account either the salt level (or TDS) or the CYA level. For the CYA level, they do have a chart in their book that has you reduce the TA by an amount dependent on the CYA and pH. The higher salt level in a salt water chlorine generator pool increases ionic strength which lowers the effective concentration of calcium and carbonate ions making the water more corrosive to plaster.

As for the CSI, I'm going to be starting a thread in The Deep End about having the CH range for SWCG raised a little bit so that people can still use the simple recommendations chart and not worry about the CSI. As it stands right now, the Recommended Levels with SWG have a lower TA and a higher CYA (both of which make the CSI lower) but have the same CH range and that doesn't make sense. Originally, it probably came from wanting a somewhat lower CSI for SWCG pools to help prevent scaling in the SWCG cell, but over time the TA and CYA recommendations changed as we learned how to have the pH not rise so quickly, but the CH recommendation didn't get changed.

 

[stevodevo]

Thanks for the input Chem Geek. I didn't want to come straight out and say the SWG recommended levels were a bit confusing when related back to the CSI, so thanks for the acknowledgment. I'll be really keen to read your upcoming post. Until then, it sounds like I'm heading in the right direction so I'll stick to my plan and keep doing what I'm doing. Your comments above make total sense to me, so I think I'm finally "getting it". This post (which I forgot I actually participated in!), somewhat addresses this subject as well - my brain hurt after I re-read it all but I think I got the main point that was coming through and onbalance's theory also seems to support increasing CH recommended levels in SWG pools, due to the modified TA and CYA level theory you mention above.


Steve.