Diy Stock Tank

jimmythegreek

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They sell 2part foam kits that you spray on. Can spray it right onto the tank walls. We pay 620 for a 600board foot pack and 275 for a 200 board foot pack. This is closed cell foam its about R5 an inch thick. Remember chlorine will degrade the galvanized coating over time, all pools have salt in them without swg. Long term an interior finish would be great and you could mold in seats etc. them finish over, or even glass the whole thing
 
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A.O.

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Apr 12, 2016
225
Kershaw, South Carolina
They sell 2part foam kits that you spray on. Can spray it right onto the tank walls. We pay 620 for a 600board foot pack and 275 for a 200 board foot pack. This is closed cell foam its about R5 an inch thick. Remember chlorine will degrade the galvanized coating over time, all pools have salt in them without swg. Long term an interior finish would be great and you could mold in seats etc. them finish over, or even glass the whole thing
Where does the salt come from if nobody added it??
 

mwemaxxowner

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I will. I didn't let the little one in until it dropped to 104. I'm going to turn the stat on the heater down a little bit and leave the digital temp controller connected also. It wasn't supposed to hit that high.

Momma stayed in the house to enjoy some quiet time, while I lured the water bug to the tub to play.

It hasn't rained in two days. Looks good and leak free all around. I have two holes I drilled to add bonding lugs, and two holes I drilled for the inlet/outlet. I used all rubber gaskets instead of any sealants. IMG_20210206_102535251_BURST001_COMP.jpgIMG_20210206_105046023.jpgIMG_20210206_102808779.jpgIMG_20210206_102806700.jpg
 
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mwemaxxowner

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They sell 2part foam kits that you spray on. Can spray it right onto the tank walls. We pay 620 for a 600board foot pack and 275 for a 200 board foot pack. This is closed cell foam its about R5 an inch thick. Remember chlorine will degrade the galvanized coating over time, all pools have salt in them without swg. Long term an interior finish would be great and you could mold in seats etc. them finish over, or even glass the whole thing


I used the dow frothpak in the crawl space in my old house. I have considered using that also. I was concerned about getting a minimal return in R value for the expense if I just spray it underneath?

I know the galvanizing will wear away and eventually it will corrode. Any attempts at coating these have usually ended miserably. I want to see how long it lasts as is. A liner for an 8' pool is something I have considered. I think at TFP chlorine levels the attack on the galvanizing from the chlorine will be minimal. Reports are 5-10 years so far before it's showing some corrosion.

I did a lot of glass work on the old boat. Maaaaan I told myself never again. Haha!

First, would you focus the spray foam on top of the foam I've already wrapped it with, or underneath the deck? I'm guessing it needs the most attention at the top where it meets the deck and down to below the water line.

We've had it open for an hour now, and it has dropped 3 degrees.
 
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mwemaxxowner

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Also, @jimmythegreek , are you insinuating that the salt added for a SWG to function will be a negligible effect on the galvanizing over just running it without a SWG? If so, if you think it's going to have a minimal effect on the life of the stock tank, I'm all for switching it over! A friend has an intex sand filter/SWG on his AGP, I'd probably use the same thing.
 

Andrew_D

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May 8, 2020
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Plastic tank?
IBC tote and cut off top, but that's only approx 3ft x 4ft.
Plastic agriculture water tank and cut the top off? They already have a 1in - 3in drain at the bottom for suction, so would just need return jets.

Andrew
 

Orion7319

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Jul 1, 2020
141
Rock Hill, South Carolina
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19775
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Salt Water Generator
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Hayward Aqua Rite (T-15)
Where does the salt come from if nobody added it??
From the chlorine, it’s in small amounts.

Nice project! I’m also just down the road from you in Rock Hill. It was cold this morning, I’m sure that hot tub felt great to get in.
 

mwemaxxowner

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It's a galvanized steel tank. It does have a ~1" drain on the bottom, but it was much easier to just drill the 2 ¾ hole and use the Intex fitting and plunger valve.

They have similar 8' plastic tanks, but I really wanted a steel one. They are more rigid, and IMO look better for some reason. If the lifespan is shorter than expected, I may rethink that. If I get 5-10 years before I need to replace it, I'll be satisfied.
 

mwemaxxowner

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We have a small group of friends we hang out with pretty often and have a game night or pool day or brunch or something. Yesterday we had them over and we soaked in the hot tub for about 3 hours, and got out about 7 pm. The girls are 5 and 7, they don't "relax", to them it's just a pool that's finally warm enough to play in. Haha! That was nice!
 

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jimmythegreek

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Do you have the ability to get 240v amd 50amps out there? They have retrofit spa pack upgrades avail for 500ish like Balboa setups that could be retrofitted into an enclosure. You could pipe in some more fittings amd have that operate with a 6k heater and a topside controller. May be able to find a used tub or a part out and use the pumps and all and have a higher end spa setup
 
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mwemaxxowner

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I do have an unused 50 amp 240 volt circuit nearby. I briefly looked at 240v heaters but the ones I saw were intended to be added with an existing controller, not standalone like this heater. I didn't dig that much either though. I saw a few diy recipes that were already built using this one and it fit the bill pretty well so I quit digging for other options.

I have two unused 240 v circuits on the pool house, one is on the wall right next to the tub. It used to power a cook top that's no longer used. I think the other 240v circuit is 30 amps, it used to run the booster pump for the rover.

I also have one more available 20 amp 120v circuit, and I briefly considered adding another heater in line like the one I'm already using, but I was afraid 4k watts still wouldn't be enough to keep up whilst uncovered, which would be the only point. Just making it redundant and unnecessary.

My sister and her husband just bought a new spa and decommissioned their old one. I have considered going to salvage parts off of it in case I ever decided I could use them. As of right now I really don't have much interest in trying to add jets and whatnot.

I will definitely do some Googling on retrofit upgrades!

I am interested in an ozonator, so I've been trying to learn more about that over the past week or so.
 

mwemaxxowner

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I follow #stocktankhottubs on IG and in a few other places since this project began. Most of what I see is something like this. Idk how in the world these hold any heat! 🤷‍♂️ It looks great though. Some of them heat by wood fire. Maybe that's how this one is. I didn't want to build a fire every time we wanted to soak in the tub.

Screenshot_20210208-100753.png
 
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jimmythegreek

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Soaking in hot water is nice for sure. Its a totally different experience when you add hydrotherapy. A bigger heater will keep temps up with cover off. I have a 4k and lose nothing with cover off in sub freezing weather. The pumps generate heat and add help hold temp. Normal tubs use air injection to add bubbles, these take ambient air and cool the water a little. In a normal tub closing the air valves helps alot in winter. Being you have a salvage tub available I would really look into scavenging the guts considering you have the power already available there. As far as ozone it's basically a chlorine killer amd helps sanitize but cant do that in it's own. You dose the tub heavily after use amd lightly every few days amd the ozone eats it up and burns off the CC. You just get the tub balanced initially and then really only worry about ph. The FC is easy with ozone
 
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mwemaxxowner

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In a jetted tub I usually think it's awesome for about 5 minutes, then I turn them off. I can't really put my finger on why but I just don't care for it after a few minutes. The option would be nice for visitors who do enjoy it though.

A lot of the salvage tub is no good. It wasn't heating and they couldn't fix it, or determined it wasn't worthwhile to fix it anyway. I guess I could get lucky and find it was something simple though. I'm expecting to find that it won't help me with heating but surely there are other parts I can strip that may be of use. Or I may want to use some day.

If you think 4k watts will maintain heat in 700 gallons while open I'll give that some consideration for sure. Either one more 2k in series or one 4k or so 240v heater. Electrically doesn't efficiency diminish with 240v, or do I have that backwards?

With just 2k watts Sunday we had it open a little over 3 hours and lost about 5.5 degrees. Ambient temps about 40. We were all still comfortable and enjoying it when we got out to eat. I'd say right now 3 hours is our threshold for needing more.

I already have the 18l (5gpm) propane heater for open use. I just have to install it.

For now I think I'll pause there and focus on insulation for the next little bit. I want to get some good baseline data for how much heat it loses while off now, so I can see the effectiveness of my next round of efforts.

Duke Energy has an app that lets me see the energy use out there at the pool house. I can see by day, week, billing period, and even per hour. That makes it easy to track changes and improvements.

With an ozonator, I see how they work, and see how easy they make it on this site, but I'm not sure about what it takes to add. I'm not certain whether it's something easy to add as a standalone product in an application like this or if they are more something that's usually built in and on the hot tub controller and more complicated. And I need to learn what size I need, etc. I'm guessing it would lower chlorine levels and help me reduce the corrosion due to chlorine over time and extend the life of the tank also?
 
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mwemaxxowner

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One of the plug options for this is just a NEMA 3 prong, meaning I guess I could just plug it in and use a timer or run it full time, no hot tub controller needed? Seems extremely simple, I want to make sure I'm not missing something haha.

 

jimmythegreek

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Ozone isn't going to save lifespan on the tub. Just helps with water chemistry. Yiu need a water feed to he able to pipeline a mazzei injector setup into. No problem running ozone 24/7 as mine does amd many others by factory default. My 4k is doing a 400gallon tub with full spray foam shell. I also have the spa pumps that give off heat but mine holds even on single speed on low. 240v is more efficient than 120v. I'd go with a 5.5 or 6kw heater for that size water. Your biggest lost is to evaporation a good cover is the most important thing. A full seam stopper is a worthwhile upgrade. Like I said look into a gecko or Balboa upgrade pack. If you can steal a pump or two from that dead spa you can get basically a hottub control amd heater setup for a couple hundred bucks amd mount the controller on the deck nice amd clean amd controls in an outdoor rated Jbox
 
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mwemaxxowner

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It won't reduce the overall chlorine use, and won't let me maintain it at fewer ppm?

I do have the temperature controller I'm using now in a weatherproof cable box.
 
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jimmythegreek

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It will reduce the chlorine that is how ozone works. But you also dose FC higher than normal because ozone eats it up. It's like a mini SLAM after you use tub and ozone eats up both the FC and the CC. If I go a few days with no use of my tub i test almost 0 FC in my tub. I dont even measure or keep schedule, I splash heavy after each use and every 4 or 5 days I add a splash. I only watch the ph and adjust as needed. In your case you will always have some chems in the water, I dont think it's really gonna make a difference if ita low or high levels, the wear would be the same in such low amounts of chlorine. Galvanized metal holds up pretty good overall, but will rust underwater, plenty of water lines rotted in the US under pressure and full of water. Can always do a liner in it, should be pretty cheap too and would last long with minimal UV exposure.
 

mwemaxxowner

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I found an 8' round liner that will work well, I just don't want one if I can get a while as is. It looks better like this, in my opinion. If we can get 5-10 good years out of it before it starts to rust, I'll be very happy. At that time I'll pop another tank in and roll on. If it's less than 5 years I will probably want to line it.

I was assuming lower concentrations would be less corrosive on the galvanizing. I see now, I'll quit focusing as much on keeping the levels as low as I can.
 

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