DIY Hot Tub, 750 gallons, Questions and Build Updates

shwn2405

Well-known member
Jun 7, 2021
52
Terre Haute, IN.
Pool Size
17200
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-9)
Yes, Keep lowering PH to 7.4-7.6. After adding MA, let it circulate for 30 mins then recheck.
 

phonedave

Well-known member
May 30, 2012
969
Montville NJ
Pool Size
17000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Hayward Turbo Cell (T-CELL-5)
So far I've used a little over a half gallon of 14.5 % MA and the pH is still high (TA down to 60). I plan to keep adding acid until the pH comes down, but is that the right move?

I'm not able to brush the plaster for the first 14 days so there's a lot of dust settled out on the bottom which are the lighter colored areas in the photo. Should I rig up a vacuum and suck it out or just leave it and deal with it when I'm able to brush?

I also still need to install the jet inserts. When the time comes I think I'll drain about half of the volume into a kiddie pool and then pump it back when I'm done.

On Saturday I didn't complete the electrical work until around 9:30 pm and when I flipped the breakers the topside controller was acting funny, and I could only get the pump to run at high speed :scratch:. Well in the morning I noticed I screwed right through the the ribbon when I screwed on the spa controller cover. Fortunately the screw pierced between two wires and didn't sever them completely so I was able to repair it and get everything working. I must say I'm really happy with how quite the pump is on low speed! You really can't even hear it unless you're right up next to it.
Plaster is alkaline, so new plaster is going to raise your pH, that is why it keeps going up (for now) and you keep adding acid to lower it.

I feel your pain about the electrical work. I just re-did my kitchen (full gut job). I put in underfloor radiant electric heating under ceramic tile. I tested the heat every step of the way to make sure I didn't damage anything. Then I decided I did not like the look of the threshold where it transitioned to hardwood floors. I pulled up the saddle and scraped off some thinnest with a thin screwdriver. That when I put the screwdriver into to cold leg of the heat. I threw on my meter and there was a high resistance fault between the hot and ground braid. Luckily, like you , I did not sever anything. I just pushed some of the ground braid into the hot conductor. I was able to pull about 6 inches of slack and performed surgery using liquid electric tape and then vinyl tape. All has tested good.
 

Dirrby

Gold Supporter
Oct 26, 2020
57
Poway, CA
Pool Size
800
Surface
Plaster
Chlorine
Liquid Chlorine
If you can not brush I would vacuum it out... Your PH is up there... where do your drop your PH to and how long does it take to get that high again?

A screw will do that every time :)
The only time I noticed any change was right after a big dose (maybe 6 oz). It was just under 8.0 so I thought I was making some movement so I dosed much less and waited a few hours and when I retested it was right back up bright red. I need to start taking better notes
 

Dirrby

Gold Supporter
Oct 26, 2020
57
Poway, CA
Pool Size
800
Surface
Plaster
Chlorine
Liquid Chlorine
Plaster is alkaline, so new plaster is going to raise your pH, that is why it keeps going up (for now) and you keep adding acid to lower it.

I feel your pain about the electrical work. I just re-did my kitchen (full gut job). I put in underfloor radiant electric heating under ceramic tile. I tested the heat every step of the way to make sure I didn't damage anything. Then I decided I did not like the look of the threshold where it transitioned to hardwood floors. I pulled up the saddle and scraped off some thinnest with a thin screwdriver. That when I put the screwdriver into to cold leg of the heat. I threw on my meter and there was a high resistance fault between the hot and ground braid. Luckily, like you , I did not sever anything. I just pushed some of the ground braid into the hot conductor. I was able to pull about 6 inches of slack and performed surgery using liquid electric tape and then vinyl tape. All has tested good.
Thanks for confirming my pH is so high from the new plaster. I thought that was the case but it's really easy to start second guessing.
Yikes, sounds like a close call. I don't think it's actually possible to get through a remodel without creating unnecessary work for yourself along the way.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
28,492
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
The manufacturer of the roll-on plaster I used specifies no brushing for 14 days in the startup instructions.

That is strange since the purpose of the brushing is to keep the plaster dust from settling onto surfaces and hardening.
 

Dirrby

Gold Supporter
Oct 26, 2020
57
Poway, CA
Pool Size
800
Surface
Plaster
Chlorine
Liquid Chlorine
FYI, Here's the startup procedure from Sidercrete:

 Place a clean rag on the end of the hose and place the hose in the main drain to prevent damage to the surface of the coating.
 Fill the pool with clean water to the middle of the skimmer or specified water level without interruption to help prevent a ring to form on the surface of the plaster.
 Once the pool is filled:
o Begin circulating the water by starting the pump and filter, and continue running 24 hours a day.
o The use of a sequestering agent/stain & scale is required (follow chemical manufacturer recommended dosage for your specific pool volume).
o Test pH, alkalinity & calcium hardness
 Alkalinity should be adjusted to 80 ppm to 120 ppm
 pH should be adjusted to 7.2 to 7.6
o Continue adjusting your pH & Alkalinity daily 153 Regur Road Hawkinsville, GA 31036 USA 1.478.892.9800 888-743-3750 [email protected] www.sider-crete.com
Revision August 2012-4
o After 5 days of constant water circulation (depending on ambient conditions – i.e.: temperatures, etc), adjust the pool water to the following levels:
 Free Chlorine: 1.0 to 3.0 ppm
 pH: 7.4 to 7.6
 Total Alkalinity 80 - 120 ppm
 Calcium Hardness: 200 - 400 ppm
 Stabilizer: 30 to 100 ppm
o After 5 days of constant water circulation, you may return your filtration timer to a normal operating cycle.
o For salt water pools, you may add salt after 14 days of constant water circulation.
 Do not add calcium chloride for the first 5 days.
 Do not add salt for 14 days in salt water systems (liquid chlorine may be used temporarily).
 Do not brush the coating or allow anything abrasive against the coating for 14 days.
 Do not use a manual wheeled vacuum system for 14 days.
 Do not use an automatic pool cleaner for four weeks.
 Additional drying time is recommended for indoor projects or during cooler temperatures.
 

Dirrby

Gold Supporter
Oct 26, 2020
57
Poway, CA
Pool Size
800
Surface
Plaster
Chlorine
Liquid Chlorine
That is strange since the purpose of the brushing is to keep the plaster dust from settling onto surfaces and hardening.
You're a lifesaver for pointing this out. I just called Sider-Crete and the tech confirmed I need to get rid of it immediately. I told him I was on day three and he was a little concerned. Off I go
 

cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
8,647
Southern OK
Pool Size
15000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
CircuPool SJ-40
If it does not come off easily you may need to brush some... but just enough to get the dust off :)
 

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Dirrby

Gold Supporter
Oct 26, 2020
57
Poway, CA
Pool Size
800
Surface
Plaster
Chlorine
Liquid Chlorine
It was too mucky to vacuum so I used a broom from the kitchen and that worked pretty good. I spent about 20 minutes brushing and stir things up with the pump on high and that seams to have worked pretty good. I got most of it up, cleaned the filter, and did one more quick 5 minute round. I'll see what it looks like when the water clears. I'm sure glad you all are here to help guide me through this!
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
28,492
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Usually a pool brush with white nylon bristles is used. That is gentle on new surfaces.

There are pool brushes with wire bristles or mix of nylon and wire bristles and those should only be used on pool walls when necessary.
 

Dirrby

Gold Supporter
Oct 26, 2020
57
Poway, CA
Pool Size
800
Surface
Plaster
Chlorine
Liquid Chlorine
That's much better. Some of the lighter spots in the picture are just a reflection of the pavilion. Now back to pH adjustments every 30 min. Note to self: by a brush.
 

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A.O.

Well-known member
Apr 12, 2016
497
Kershaw, South Carolina
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
I have had a lot of brushes over the years for my pools, this one , to me anyway, is heads and tails above the rest, and not so big you couldn't use it in your tub.

 

Dirrby

Gold Supporter
Oct 26, 2020
57
Poway, CA
Pool Size
800
Surface
Plaster
Chlorine
Liquid Chlorine
I have had a lot of brushes over the years for my pools, this one , to me anyway, is heads and tails above the rest, and not so big you couldn't use it in your tub.
Much appreciated. Looks like a winner
 

phonedave

Well-known member
May 30, 2012
969
Montville NJ
Pool Size
17000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Hayward Turbo Cell (T-CELL-5)
Thanks for confirming my pH is so high from the new plaster. I thought that was the case but it's really easy to start second guessing.
Yikes, sounds like a close call. I don't think it's actually possible to get through a remodel without creating unnecessary work for yourself along the way.

My problem is I fix everything. If I was a contractor, I would ignore things. Like if you hired a contractor to move an outlet, that is what they would do. If while doing so they noticed other things that need to be done they would leave it. Me, I feel the need to fix everything I see, so even the smallest of projects becomes much larger.
 
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Dirrby

Gold Supporter
Oct 26, 2020
57
Poway, CA
Pool Size
800
Surface
Plaster
Chlorine
Liquid Chlorine
I downloaded the pool math app and began logging additions. What a great app. Today I averaged 2 oz of MA (14.5 %) per hour. That sounds like a lot but what do I know. I have 3 oz of stabilizer soaking in a sock which should net 30 ppm in addition to what little I started with. Looking again at the plaster startup instructions it actually states to not add chlorine for 5 days! I guess reading all of the posts on here about NEVER letting chlorine levels get low has me a bit concerned going that long without it. The water still looks really clear and smells "clean," if that's a thing. I measured the dimensions for pool math and found I'm right at 800 gallons instead of the pre-build estimate of 750 :D
 

Dirrby

Gold Supporter
Oct 26, 2020
57
Poway, CA
Pool Size
800
Surface
Plaster
Chlorine
Liquid Chlorine
I ordered a cover from Beyond Nice on 09/03 which should arrive late October. In the meantime I am working on finishing the enclosure and insulation. I did a 1 hr. test and noted a temp increase from 75 to 79 °C and measured current at 1.3 A in filter mode and 33 A while heating. No surprises there. I pay 0.41 cents per kW hour so I am very curious how much heat will be lost through the uninsulated slab. I’m guessing a lot - so I’ve been looking into what it would take to incorporate solar heating and am keeping an eye on craigslist for a good deal.

I bought a bunch of foam panels to use for insulation but may instead use mineral wool. If anyone has any thoughts on that I'm all ears.

For the removable side panels I framed them out with 2x4s, used roofing tar paper as the moisture barrier, cement board for siding, and PVC trim for top and bottom. The paint is Behr elastomeric in “legendary grey.” The panels in the last photos are not yet bolted in, just propped up, because I grabbed the wrong size T-nuts from home depot and didn’t want to make another trip yesterday. To be honest I am not completely sold on how they look. I don't know what, if any changes I'll make, but I'll continue to mull it over. Redwood siding might be a good option.

Side note: We were hoping to kill off all of the crabgrass and reseed tall fescue this month but never got around to it. It's a bummer, but we'll have to push that project to early next spring and enjoy looking at our dead crabgrass all winter.
 

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A.O.

Well-known member
Apr 12, 2016
497
Kershaw, South Carolina
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Crabgrass, schmabgrass... it's green isn't it :)
Yeah, my "yard" is a combo of grasses and weeds... and its green too, I like it just fine.
If you keep that tub hot all the time that slab will turn into a heat sink and wont hurt you a stitch!
Oh, and looking good!
 

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