New Pool - need help getting chemistry right.

[rugadog]

Hi All,

It's been a while since I posted last. We ripped out our old vinyl pool had a new pool completed the 11/23/11 (The day before Thanksgiving) ~ I will post construction pics and video in another thread and the story of how I ended up having to balance the pool myself versus the contractor handing me over a pool with the water balanced.

I have a TF-100 kit I purchase in summer 2010 which some of the reagents are probably expired. I will be purchasing another kit today. Using that kit and a new Taylor K-1000 and measure the following:
FC: 0
CC: 0
TC: 0
pH: 7.8
T/A: 80
CH: 200+
CYA: 0

I am running to Home Depot next to pick-up more chlorine. The SWG is not generating chlorine because of the water temp. is 49*F. In the past two weeks I have added six gallons of Chlorine and the level drops like it's a HOT day in July.

Please advise where I should start. Should I work on getting my other levels up first?

The PebbleSheen contractor was here yesterday to fix some issues in the notched rock work he did and saw some scaling on the sheen walls already (it is a Onyx Black sheen so scaling is very easily noticeable.) He asked where my pH level was and said I need to keep it on the lower end around 7.2. So I need to work on getting that down too.

I look forward to hearing from you guys!

 

[duraleigh]

1. He is right about your pH....keep it down where he suggested.

2. Need a better test of CH. What about the test kept you from getting a more accurate reading? Please test your fill water for CH as well and post that, too.

3. Get CYA in your pool....sooner rather than later. Use the pool calculator to dose your pool up to around 60ppm.

4. MOST importantly, you need to keep chlorine in your pool. The CYA will help you do that but you need to keep around 3-4ppm in your pool all the time.

Have you read Pool School? I can't determine if you understand the CYA/FC relationship from your post. Let us know.

Tell us what your water looks like. You most probably need to shock the pool but let's collect some more info first.

If you have kept your kit in controlled conditions, the reagents are likely just fine. Is the R-0600 in the K-1000 kit (the old one) discolored?

 

[onBalance]

Don't be too quick to assume that the pool is scaling. Did you brush the entire pool sufficiently during the first month? If you didn't, then it may be scale afterall.
A simple sanding or scraping where it is "white" should remove recently deposited scale and expose a smooth surface underneath. If it is not smooth underneath, then there are other issues at play, and the color may be fading. Lowering the pH and making the water more aggressive may just compound the problem.

 

[duraleigh]

A pH of 7.2 is harmless. Given the unknown CH level, a pH of 7.8 is less safe (although still ok if it doesn't slip higher) I believe you got good advice to lower pH down. Posting an accurate CH will be helpful.

 

[rugadog]

Thanks for the reply guys.

I will take CH tests of the pool and fill water again and use the "fading endpoint" instructions and post later this morning.

I am going to go to Leslie's and get stabilizer this morning. The pool calculator says I need to add 320oz of stabilizer does that sound right? How do you recommend I add that...all at once, half or a little at a time. I've read it takes a while to dissolve into the water.

I read that stabilizer will also drop your pH so I will wait until after the stabilizer is dissolved and I get my CYA to the right level before I add any muriatic acid.

I am also going to have Leslie's test my water while I'm there.

Thanks again for your help. I'll post the CH readings in a bit.

 

[onBalance]

Duraleigh, I have a tendency of not being detailed when I post responses, and should have been. I understand your position on this. Please let me offer an explanation to my madness.
I agree with you if the CH is 350 ppm or higher, and the pool has scale everywhere (as the plasterer says), that a pH of 7.2 would be nearly harmless, and may help remove the scale.

However, if the CH is between 200 and 250 ppm, then a pH of 7.2 would result in a SI of about -0.7, with the temp of water at 49 degrees. If the pool does not have scale, and the plaster is of poor quality, very soft and porous, and is streaking and turning whitish, then making the water more aggressive is the wrong thing to do. Since this pool was just recently filled, and that some northern areas of California have soft tap water, the CH may not be high.

Also, adding either acid or CYA (to lower the pH) will also reduce the carbonate alkalinity and make the SI even more aggressive. If Rugadog (pool owner) has over-estimated the size of his pool, then he may overshoot his target of 7.2 when adding the chemicals, with the resulting pH going below 7.0. That can’t be good for the plaster and the equipment.

Another thing, the National Plasterers Council (NPC) states that any water lower than the “Ideal” ranges set forth by the APSP is aggressive. That means any water with a pH below 7.4, or a TA below 80 ppm, is automatically deemed “aggressive,” and it doesn’t matter what the SI actually is. Further, the NPC states that pool water should never be allowed to have a negative SI, ever! Yes, I know that position by the NPC is wrong and ridiculous.

So if this pool plaster actually has some problems and a NPC inspector comes out to inspect, and determines that the water has been aggressive; whatever problem it is may be blamed on aggressive water. Rugadog will be in a difficult situation trying to prove that the problem is actually a plaster workmanship defect. That is what I am concerned about.

 

[rugadog]

A few more things:

duraleigh:
I have my FC at 5.0 now.

My CH is right at 200 after re-testing and using the "fading endpoint" instructions for both the pool water and fill water.

I have read Pool School many times and understand the CYA/FC relationship. I used this website and your TF-100 kit to bring my pool back from a green swamp in 2010. ~ :-D My main concern is what to add first stabilizer or muriatic acid. I now think I understand that the stabilizer should go first because it will drop the pH.

My water looks great! It is not green or cloudy at all.

My R-0600 is new, I just bought a replacement bottle at Leslie's last week.

Please let me know how much stabilizer to add at a time...the calculator says to add 320oz

Also I read in Jasonlion's Extended Test Kit Directions for testing CYA that the water should be at 70* before testing. The TF-100 instructions didn't state this so my test water was straight out of the pool and was 49*. Could that 20* be causing my CYA to be low?

onBalance: I have brushed the pool once since completion and will do it again this weekend. Is it normal for pebble sheen to fade within a few months of completion?

(I just read your reply from today)
Could you please define "SI"?
You say plaster, and I think pebble sheen can be described as plaster too (I've heard my contractor say this) but I just want to make sure you have a clear understanding of my pool.


Thank you both for your interest and help.

 

[onBalance]

Rugadog, the "SI" is actually the Langelier Saturation Index, or as this website uses, the "Calcium Saturation Index" and is also part of the "calculator". It determines whether the water is aggressive, balanced, or scale forming.

Please be sure you the gallonage of your correctly. A 20 foot by 40 foot pool generally has about 30,000 gallons. I wouldn't think a residential pool has more than 35,000 gallons. Is your pool bigger than 20 X 40?
After adding stabilizer, you also need to add some sodium bicarbonate to raise the alkalinity (TA).

Yes, pebble sheen is a good product, since it contains "cement" it is a type of plaster. No, the color should not fade for many years. That is why I am wondering what actually is occuring about the plaster. I would think you should have brushed the pool more often, but if you also have an automatic cleaner running around the pool, then that may have done the same thing. Please check to see if an actual deposit of white "crust" is on top of the plaster surface.

 

[rugadog]

Thanks for the "SI" definition.

Our pool is 50' X 28' X 3.5' - 8.5' deep + 8' X 14' X 10'' deep shelf. Pool is an irregular shape so calculating the volume is going to be difficult.

My Polaris has been running everyday for about the past month.

The pool shop (not Leslie's, an independent shop) tested my water for me and the results are as follows:

FC: 5.0
pH: 8.0
T/A: 90
CH: 150
CYA: 0

I'm going to add the stabilizer in the morning. The pool shop said to just add it to my skimmers through out the day.

I will also brush the pool and try to determine what the white-ish color is that is showing up in places.

I plan on taking measurements and sitting down with the design plans this weekend trying to figure out the volume this weekend.

 

[duraleigh]

Your pH of 8.0 is too high. The forum guidelines are for pH to fall somewhere between 7.2 and 7.8.

 

[rugadog]

duraleigh: Will the stabilizer lower the pH? I am still looking for an answer regarding: My main concern is what to add first stabilizer or muriatic acid. I now think I understand that the stabilizer should go first because it will drop the pH. Can anyone help me with this?

Should I add the Muriatic Acid and the stabilizer at the same time?

Thanks

 

[onBalance]

Yes, stabilizer (CYA) will lower the pH somewhat. I suggest adding the stabilizer first and see what the pH ends up at, and before adding any acid. From your latest tests, it looks like you should also add some calcium chloride to raise the CH up to at least 200 ppm, or as this website suggests, 250 ppm. If your pool is 40,000 gallons, then 20 lbs. of CYA will add 60 ppm. And try to feel the whitish areas with your fingers to see if it is rough to the touch.

 

[MattM]

Remember to add the cya via a sock in the skimmer - it might take awhile. Note that the pool will have trouble keeping chlorine while ph > 7.8. I'd be a little worried about your TA getting lower with very cold water but ph might balance it out. Note that some of the standard recommendations for ph when starting pools assumes a summer start, you probably want to experiment with the pool calculator and see how CSI changes when ph, ta, and temp goes up/down....the recommendations for cold versus warm water can vary quite a bit. Still, following general guidelines from this site and having a good program to estimate impacts on csi before making any changes should help quite a bit.

 

[Richard320]

Pool Calculator is your best friend here. Bookmark it. Be sure to enter the proper gallonage, and down at the bottom it will let you select chlorine source and surface material. Then just plug in your values and let it tell you what you need. You can also experiment with changing CYA or whatever and see the effect on CSI.

But I wouldn't dose it based on a pool store's tests. There are countless posts in here about wild discrepancies between different stores' tests versus self-test, and even two samples drawn side by side but told they were from different pools.

Once you have test results you can trust, get the pH right, that's easiest. Once it's mixed - an hour or so pumping, plus some brushing - add your chlorine. CYA granules go in a sock or nylon in front of a return. Or in a sock tied to a pool noodle. Don't waste reagents checking CYA for at least a week.

Each time you test and dose, you'll get a little closer to perfection. And you'll also learn whether your volume calculations were correct, because you are consistently higher or lower than your expected results. Once you're dialed in, it's really easy to maintain balanced water.

I certainly hope you ordered refills for your TF100 already.

Without a good test kit, balancing your water is like painting a portrait in a blackened room. Sure, paint will get on the canvas, but you won't like the results.

 

[rugadog]

Thanks again for all the replies.

Over the weekend I calculated the volume and it is 44,000 gallons.

I also, added 16# of CYA, chlorine, muriatic acid and brushed the pool.

This morning I tested with got the following:

TC: 5.0+
pH: 7.2

I will test my CYA next weekend.