Pool Opening Spring 2025 - Removing the Leaking Heater Manifold

ajw22

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Jul 21, 2013
65,062
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Opened my pool today. Some observations:

  • Pool opened up pretty clean. Water temperature was 49F. Leaves all vacuumed up. See pics below.
  • I added borates the end of last year and did not see any winter scaling.
  • pH tested way high and added 40 oz of MA to begin working it down.
  • I had 4 gallons of 12% chlorine with a date code of May 2024 in the garage. Added it to the pool. If full strength it should add 3PPM/gallon or 12 PPM. Tested at 6 PPM. So the LC became half strength after a year.
  • Replaced the booster pump that had a bad bearing whine with a new PB4-60.
  • Nipple on the Polaris 380 the flexible hose connects to broke off at a seam. Plast-aid seems to have fused it back together. If it does not hold then a new feed tube is $20.
  • Looks like my 10 year old MasterTemp heater developed a crack in the manifold that rusted the bolts and sensors. Heater still fires and works. I need to see if the rusted bolts can be removed to replace the manifold or it will be a new heater.
  • Need to replace some diverter valve stem O-rings that appear to be leaking before they rust out the actuator motor.
  • Cover has a hole in it. I need to lay it out on the driveway and patch it.
Always something. I have a few projects this spring.

Pool 2025 1.jpg

Pool 2025 2.jpg
 
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George?

Season 2 Bltn GIF by NBC
 
I may do the same this week. Good to hear where NJ neighbor temps are so I expect similar. Today is going to be a sand filter deep clean day.
 
My SWG came on yesterday so I'm in the low 50s also. It was warm a few weeks ago when opened but it quickly cooled off until now.
 
I opened March 16th in Missouri. My water is now staying above 60°, but we had rain, rain and more rain! 3-5 more inches expected over the weekend. Now I have visitors.

IMG_1448.jpeg
 
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@JoyfulNoise @JamesW What would you say the pH was at opening if it took 3 gallons of 31% MA to lower the pH to 7.5? TA 70 and 75 PPM of borates.

Plast-aid fixed the Polaris.

Fixed the leak in the booster pump drain plug with some Pool Lube.

I don't know if these bolts are going to come out. This heater may need to be put out.

IMG_0272.jpeg
 

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1745092271395-png.639185


This note does not apply to that amount of pH change and the calculation is reasonably accurate?

Results are approximate and can be off significantly for large pH changes.

So the Old Pool Math page works better for this type of change then Effects of Adding which tells me each gallon lowers pH by 0.9. 3 gallons should have lowered pH by 2.6 or 2.7 according to PoolMath app Effects of Adding?

That did not pass a reasonability test that pH could have been around 10.

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Was the 70 TA before or after adding the acid?
After. Didn't test before beginning the acid additions.

I closed at TA 70 and my fill water is about that.

Pool took the same 3 gallons of MA at opening last year.
 
I wish that @chem geek had taken this table out to pH in the high 8's.

It does look like pH 8.3 would be equilibrium around TA 70-80.

CO2_Out_of_Equilibrium.jpg
 
After. Didn't test before beginning the acid additions.

I closed at TA 70 and my fill water is about that.
Fill water TA is 90.

I added about 25% of the pool based on closing salt of 3,000 and opening salt of 2200 after filling the pool.

So TA at opening should have been around 80.
 
Borate makes a big difference.

With borates, the starting TA was 113 and the starting pH was 8.26.

Without borates, the starting TA was 113 and the starting pH was 9.9.

View attachment 639210
View attachment 639211
That is VERY interesting.

At April 2024 opening I had some winter scale with the pool taking 3 gallons of MA without borates.

I added the boric acid in September 2024 and this year it wintered with borates and had no scale upon opening. Still took 3 gallons of MA at April 2025 opening.

I think this demonstrates the reason borates can prevent high pH in a closed pool and winter scaling.
 
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So TA at opening should have been around 80.
1745095922187.png
70 + 43 = 113.

If the TA was 70 after adding 3 gallons of acid and 3 gallons of acid lower the TA by 43 ppm, then the TA had to be at 113 before adding the acid.

Most likely, you had some hydroxide and carbonate from the plaster that raised the TA and pH.
 
View attachment 639217
70 + 43 = 113.

If the TA was 70 after adding 3 gallons of acid and 3 gallons of acid lower the TA by 43 ppm, then the TA had to be at 113 before adding the acid.

Most likely, you had some hydroxide and carbonate from the plaster that raised the TA and pH.
Note to self - test TA at opening in April 2026.
 
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