Painting fiberglass baptistry

[Aggie_ChE]

Because I am a pool owner (and a retired guy), I am in charge of my church's baptistry. For several years we keep water all the time in the baptistry and warm it up every Saturday in case someone wants to be baptised on Sunday. The baptistry is fiberglass, about 400 gallons. I maintain the chemistry pretty much like a pool, 30 ppm CYA, 70 TA. I bump the chlorides to shock (12 ppm) on Sunday after services and the next Sunday I still have 2-3 ppm chlorine remaining. I drain, clean, and refill every other month. (We really don't have many baptisms. Most of the time no one is baptized between fillings.)

The sidewalls, and to a lesser extent, the floor have been looking pretty bad for a while, and I am sure the constant filling and chemicals do not help. (See the photo.) I would like to paint the baptistry so it looks better, to protect the walls, and extend the life of the baptistry. I would like the paint to last a while, 5-10 years. From reading, epoxy pool paint seems like my best bet. Any suggestions on prep and brand of paint?

Thanks!

 

[RDspaguy]

You do not need CYA in an indoor unit. In fact, it is a health code violation in some places. I always recommended a bromine maintenance system for baptismals. Treat it like a hot-tub, because that's what it is.
I would not paint it. The stains are the result of cracks in the acrylic and high sanitizer. They should clean up with muriatic acid (be sure to ventilate) and elbow grease. A magic eraser might work magic on it, too. TSP (or another magic eraser perhaps) will get the shine back to the tub. Then lightly sand and seal the cracks in the acrylic with an acrylic clear coat.
If you are just sick of that color (and who wouldn't be?) I would use a bathtub refinishing kit, or maybe 5 kits in this case. A bit pricey, but I had fantastic results with it. Looked brand new and very durable. As with any adhesive, surface prep is everything. Muriatic, tsp, and sand everything.

 

[Aggie_ChE]

RDspaguy, thanks for the quick reply. You seem like EXACTLY the resource I need.

The reason I have been adding the CYA is because of a recommendation that "You will want some CYA in the water, not for protection from the sun, but to buffer the harshness of the chlorine." from this 2016 thread when I was asked to take on maintenance of the baptistry. Troublefreepool.com also recommends CYA addition to spas in this thread that is also referenced in Pool School.

There was some brown discoloration in the baptistry walls when I took over baptistry maintenance. I guess that 2016 was the first time that CYA was added to the baptistry, as to my knowledge, this was the first time it was decided to keep water in the baptistry in the history of the church building dating back to 1968. (I have no idea when this baptistry was built.)

Can you tell me more about how to try and clean the stains? I am familiar with TSP and the Mr. Clean Magic Erasers. From pool pH adjustments, I also know and respect muriatic acid. What dilution of muriatic acid should I use? How it is best to apply (sponge or pump-up sprayer)?

I really don't care about the color. I just want the baptistry to last without leaking. I will look into acrylic clear coat.

 

[RDspaguy]

50/50 with water in a bucket and a green scrubby sponge. Spraying indoors would not be good. Might want to wear a chem mask if you are sensitive like me. (I do not meam emotionally.) And vetilate the area with fans, open doors, etc...
From the looks of it, I'd say it's a 1968 model.

 

[RDspaguy]

https://www.aquaticsintl.com/facilities/maintenance/cyanuric-acid-good-or-bad

TFP has a ton of great info and recommendations regarding chemical maintenance. I have not read it all. I can only speak from personal experience, and that experience is that cya is not allowed in indoor units in some places I have worked. And that I do not recommend it's use in an indoor baptistry. I would suggest you check local health dept requirements. Baptismals slip through the cracks as public and do not generally face health dept inspection, but I personally believe that they should. And if, God forbid, there ever was an issue, you will want to be compliant with local regulations.
I have worked on quite a few over the years and have seen some pretty bad situations that sent children to the hospital. (Not from cya, but poor sanitation). One kind old gent looked me in the eye and said, "but it's HOLY water". That is a true story. His faith humbled me, but I still put him on bromine.

 

[Aggie_ChE]

50/50 muriatic acid sounds like some pretty strong stuff. When I was a dumb college freshman at Texas A&M, in a brand new building for science labs, I was mixing sulfuric acid into water as I was walking. Clumsily I spilled the acid on me, eating the bottom half of my shirt off, burning holes in my jeans, and giving me a few little spot burns on my stomach. I did have to endure the humiliation of being the first person to go under the safety shower in the history of the building. Standing around without my shirt on after the lab I did get a date, though, with a cute girl in the lab. Ha ha.

I will look into a chemical mask. Years ago I had a mask for benzene and thought with a cartridge change I could use it; However, I can't find it. A lung full of vapor from straight muriatic acid is "breath-taking" so I probably need something. Maybe that makes me sensitive (but not in an emotional way), too.

That you have baptistry experience must be quite unique. My Google searches on chemistry of baptistries in 2016 came up empty. That you have run into multiple hospitalizations, WOW!!! The Bible teaches the importance of baptism. However, I never thought of the water itself as something special. However, for fun I do tell people I am adding "Holy Ghost" to the baptistry when I am adding my liquid chlorine

I am confused about using bromine and there is not as much info as chlorine. Here is the best Troublefreepool.com article I found. Please confirm that I understand correctly the process for each baptistry refill. 1) Add baking soda as needed to get TA around 50. 2) Adjust pH as needed. 3) Add sodium bromide per label. 4) Shock with either liquid chlorine or MPS (non-chlorine shock) to activate bromide to bromine. 5) Shock weekly. I guess I can use an OTO test kit to measure bromine and pH before my weekly shock to confirm that I have 2-6 ppm free bromine, adding liquid chlorine or MPS to boost the brimine.

From Troublefreepool.com, I am very familiar with the concern of elevated CYA, and that is why I switched from trichlor tablets in my pool.

I have a call in to the city health department about their recommendations and requirements on baptistries, but with Coronavirus stuff I could only leave a message.

I appreciate ALL of your recommendations.

 

[RDspaguy]

Happy to help.
Yep, that's bromine maintenance in a nutshell.
To be clear, though I said "children", I am only aware of one that suffered a bacterial infection attributed to the baptismal. I was there after the fact, in response to the issue. And, surprisingly, it was not the kindly old gent who was surprised you needed chemicals in blessed waters. He never had any issues to my knowledge, so maybe his faith was enough.

 

[Aggie_ChE]

Thanks much for sharing your expertise, RDspaguy!

 

[Aggie_ChE]

Two more question, RDspaguy.

1) What acrylic clear coat do you recommend using to seal the cracks and surface of the baptistry?

2) Do you have any experience with Acid Magic, which is marketed as a buffered muriatic acid that is much safer for human skin and has 90% less acid fumes while providing about the same acid cleaning and etching power as 20 degree Baume muriatic acid. It is not that expensive ($20-25 per gallon), and safer and less vapors for using inside all sound really good, almost too good.

Thanks!

 

[RDspaguy]

Frankly, I have done maybe a dozen acrylic repairs. It's not something I see enough of to have a preferred brand. I suggest you google some how-to videos and see what guys who do this stuff everyday are using. They might be doing it to a boat or something, but it's all the same.
Never heard of that stuff. But anything that reduces the fumes is worth it. I wouldn't use it to acid wash my plaster or anything without a bit more research, but it should work to dissolve those stains. For that matter, some CLR or something along those lines might do it with the help of a little Emery cloth and some elbow grease. You have to sand it anyway. With a bit more elbow grease you might not even need CLR.

 

[Aggie_ChE]

Thanks again!!!