Just opened and have a high CH - now what?

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tj_royersford

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Apr 24, 2009
30
Philadelphia PA area
I just opened my IG plaster pool. It was built last summer (opened it on Labor day). After getting the equipment up and running I made my first round of measurements with my new TF100 test kit. Here are my readings:

FC, CC, TC = 0
pH > 8.2
T/A 160
CH 870
CYA 25
Temp 57 deg

I expected the FC, CC, and TC to be zero and the pH to be high (new plaster pool and all). But the CH reading seems off the charts (I assume because of new plaster?). I'm planning on tackling the pH first with MA and adding bleach to get the FC up. Once it's up there I'll fire up the SWG.

Any advice on the CH? Should I just wait until I get the pH under control and then check it again?

Thanks in advance. I've been lurking for the last several months and the forums have been a big help.
 
The first thing to do is to get the PH down to between 7.2 and 7.4 right away. Right at the moment, you are well into the range where I would expect some calcium scaling on the pool. It would be a good idea to check out the pool and see if there is scaling and if so how much it bothers you. The cold water will have slowed down any scaling so it might not be significant, but then again it could be fairly bad.

Assuming the scaling isn't bad enough to warrant an acid wash, now is a good time to do a substantial amount of water replacement. With some care it is possible to maintain a pool with CH levels up to 1,200, but it gets progressively more difficult as you approach that level. Things will be much simpler if you bring the CH level down now.

Since you live in PA, it isn't all that likely that your fill water CH level is all that high, but that is a good thing to double check.
 
Several hours later and the pH is still > 8.2. Added another 2 quarts of MA. FC is starting to come up, now at 1. Spent the day vacuuming white powder off the bottom of the pool. Some of it appears to be salt crystals (had a nice bag of them in my cleaner bag), the rest appears to be white cloudy "floaties". Had to backwash once already as well.

Should I hold off on the water replacement until I get the pH under control? Either way, when I go to do the replacement, how much should I drain out before filling? Do I need to worry about the hydrostatic pressure popping t he shell out if I drain too much?

Thanks!
 
This mornings results are:

FC, CC, TC = 0
pH = 8.2
T/A 120
CH 650
CYA 30
Temp 60

pH was a little better, I've put over a gallon of MA in and 2 gallons of bleach to get to this point. Just added another 2 quarts of MA and another gallon of bleach (time to go get more of both). Also going to get some CYA so I don't keep losing my chlorine.

Tested the tap water, it had a CH of 370. So not too bad.

My initial CH reading may be artificially high due to my testing process. As one of the 7% of males that are partially color blind, I didn't trust myself so I grabbed my designed color interpreter (8 year old son). The second time I used my 13 year old son. For the tap water I used my 10 year old daughter. So I'm having to calibrate them as well as my water :)

Since it's a new pool, I'm battling the new plaster and the pH. Now off to get more MA...
 
more MA added.

Went to local pool store to get CYA and had them test the water as well. Their results were:

FC 1.45
TC 1.44
pH 7.9
TA 100
CYA 25
Total Dissolved Solids 240 ppm
CH 100
Iron 0
Copper 0.06

Everything seems in line with my measurements (keeping in mind that I had added MA and bleach after this morning). But the CH of 100 is completely off. Which begs the question why? I noticed that when I add the drops of R-0012 that my drops seem very small compared to the drops from the rest of the bottles in the TF kit. Is that expected, or maybe my bottle's just off? That might explain why I'm getting such a high CH since I'm counting lots of little drops. How blue should the test sample get? I've been going with any blue at all.
 

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pH 7.4; TA 107; CYA 40; TC 3ppm; borates 40; temp 80F. The water is crystal clear and no deposits in sight...

I just have to say that I am having this little quandry with TF test kit and CH as well. My CH was 500 last year; I was still attributing this to the new plaster, 07. This year, after emptying 1/2 the water and starting fresh with 180ppm CH in the fill water (per the test kit) the tester says over 600 CH in the pool. The pool store tester just now says total hardness 327 (times 2/3 for Calcium) ought to be about where I would like it. I am not putting ANY Ca++ in the pool....

Somethings causing a false positive---too many drops, too big drops. some other outlyer--I cant figure it out. Maybe Ill just get a dip strip for the Ca....
 
Try wiping the tip of the calcium titrant bottle with a tissue and see if the drop size settles down to match the drops from the other reagent bottles. Sometimes a static charge builds up on the tip and that can affect the drop size.

When doing the CH test you are looking for a color change. When the color starts changing, you continue adding drops until a drop does not make any further change in the color. Do not count the final drop which does not change the color. The exact color/shade that the sample ends up with will not always be the same.
 
I added 4 lbs of CYA yesterday afternoon and by evening eldest son was reporting a pH of 7.4. Had to go out of town, so my designated test lackeys will continue reporting pH to me until I'm back. I'll focus on holding at 7.4 and recheck the CYA and CH when I get back.

Thanks for the tip on the static charge thing and the color change. I'll try it when I get back. I'm betting that I wasn't doing the test right.
 
Back from trip and have new measurements:

FC 1
CC 1.5
TC 2.5
pH 7.6
T/A 120
CH 520
CYA 35

pH is doing better and the 4 lbs of CYA I added 4 days ago has helped. I've also tried improving my CH drop technique... So, based on my pool school lessons and the pool calculator, I think I have the following actions:

1. Continue bringing pH down in order to prepare for aerating to bring down the T/A.
2. Add another 4 lbs of CYA to bump up the CYA. It won't get me to my goal of 60 yet, but I'm taking a bit of a "sneak up on it" approach since fixing it requires draining.
3. Get more chlorine in the pool to bring FC up to 4. I haven't shocked yet since opening. If there are no problems, should I worry about shocking? Pool had an opaque cover on it all winter and the water actually looked pretty good when we opened.
 
Yes, you should shock. :wink:

Tj, you don't list a salt result? :?:

Your CYA should be at least 70 before you run the SWG. Pool Calc shows over 8 lbs will be needed to raise you to 70 from 35. I do understand your hesitation, I just wanted to point out that you shouldn't run the SWG until the CYA is in range.

As for shocking with Dichlor, yes, you can use it if you like in this situation. According to the pool calc, it won't add much though. I calculated 94 oz of Dichlor to reach your shock level of 14, which would only raise the CYA by 12. But I suppose it's something, and if you use the Dichlor more than once it would increase it further. Be sure to use the "effects of adding chemicals" section to determine how much CYA the Dichlor additions will be adding to your pool.

Also just wanted to add that even after you lower the TA thru acid/aeration, you may still see the PH creep up, as Plaster can take a year to cure and you see this PH rise as a result.

My advice, skip the lowering TA thru acid/aeration step. Your TA is not extreme by any means and with the routine dosing of MA to lower the PH back down over time the TA will drop as well, eventually coming in to range. As long as you stay on top of the PH with the acid additions you should be fine.

Just focus on your shocking and bringing your CC down. Remember, when the FC is above 10, the PH will read a false high. Only adjust the PH when the FC is below 10. :goodjob:

Hope this helps. :wink:
 
tj_royersford said:
...pool school articles about shocking. Since my CC is 1.5 it sounds like I should shock. Since I also need to get my CYA up, it seems like dichlor might kill two birds with one stone rather than just adding bleach. Does this seem reasonable?
Click to expand...
...edit to remove comment on dichlor...

The best way to shock is going to be with liquid chlorine (10 or 12%) from a pool store OR just good old 6% bleach (as in from Wally World): The SWG doesn't produce enough chlorine fast enough to shock.

Did the 4 Lb of CYA come from the pool calculator? To get from 25 to 60 I show a need for 140 oz. (8-3/4 lb) to get to a CYA level of 60: the low end for the SWG.
You added 4 lb. on Monday, 05/10: Unless you used liquid CYA, it'll take up to a week to fully dissolve.
Adding another 2 lb will not hurt you (and still allow you to "sneak up" on your target#). It will help in chlorine loss due to sunlight & your SWG needs the higher level of CYA.

Your PH is on the high range of normal and running the SWG should cause the PH to increase.

Personally, I'd stick with basic chemicals (CYA, chlorine, and muratic acid) 8) .
 
Thanks for all the tips!

I didn't post a salt result because I don't have one - not sure how to get it. The TF kit doesn't do it. Somewhere in the forums I think I read about a separate test strip or something? When I swing by the pool store to get more CYA I'll see if there is a salt specific test. After first getting everything installed last year my Pool Pilot used to complain it needed the salt added and give me a PPM reading. But now it doesn't complain and I haven't figured out how to get a reading from it. Maybe I need to do another deep dive into the manual.

I was planning on using external chlorine to shock. I've been using bleach so far, so I'll pick up some more. Using the Chlorine/CYA charts and a CYA of 35 it looks like my shock level is 14 (using the non-SWG table). So that means adding ~7 gallons of bleach. I may have kids wanting to jump in tomorrow afternoon, so is it ok to start the shock tomorrow evening?

My original CYA calculation was done using the pool calculator and I think I came up with around 6-7 lbs (sorry, it was last week). But since this was my first time adding it I wasn't sure how much it would drop the pH so I chickened out and went with 4 lbs (solid). I'll pick up another 4 lbs and add half of it. I made the mistake of spreading it along the entire pool instead of the skimmer/sock trick.

Thanks for the tip on the TA. I'll skip it for now and keep managing the pH, FC, and CC.
 

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