Time sensitive: COLD PLUNGE TANK


New member
Mar 25, 2017

I'd am building an 8x8x4 deep plunge tank in Hawaii and have some questions and would love a gut check. I am pouring concrete tomorrow - so any help much appreciated.

* All concrete.
* 10" walls and 10" floor. (See image)
* 20" will be below grade & 28 inches above grade
* 6" Water line below top of tank
* used for cold tank
* 1500 gallons
* Will have a hot tub cover over it to keep clean (that is why the size is 8x8 to use same cover size as hot tub)
* Will use an AquaStar Channel Drain, with center drain leading to garden for wash out and two side drains feeding back to pump
* Two (2) inlets
* Two (2) returns
* One (1) overflow

Screen Shot 2017-03-25 at 4.51.06 PM.jpg

Here are my main questions:

1. Skimmer: do I really need a skimmer? Or can I just get away with 2" return close to the water line with screen in the intake? If a skimmer is highly suggested, any suggestions on a low profile front access skimmer??

2. PVC: 1.5" or 2"? I am planning 1.5" for everything but the drains which I will use 2"

3. PVC and concrete: I am planning to just pour concrete right around the PVC pipes. Should I be using "No Wet" Flanges? I just heard about them but can't find any information on them.

4. Grounding? Does the rebar need to be grounded?

5. System: I am planning on using a 1/2 HP pump, 40 gal sand filter, UV lamp and an Elkay water-to-water chiller (I think it’s the largest package chiller they make)http://www.pittsburghwatercooler.com/ELKAY-ERW32-32-GPH-Water-Cooled-Remote-Water-Chiller_p_686.html

Thanks in advance!


Ps. I am new here. A wonderful community you have here. I love the internets! I have searched the forums for advice on building a cold plunge pool but haven't been able to find much.



TFP Expert
LifeTime Supporter
Jun 7, 2011
Midland TX
Aloha, Aloha!

Welcome to TFP!

Most of us are just pool owners here, but there are a few who might give you some good feedback. Good luck on your project!


Bronze Supporter
LifeTime Supporter
TFP Guide
Jun 3, 2015
Welcome to the forum!

I really don't have any experience with a cold water tank, but wanted to comment on your question regarding 'grounding' the rebar. The rebar needs to be bonded with the pump, water, decking/patio/walkway around the pool, and any metal objects like ladders within reaching distance of the pool.

Bonding is not the same as grounding. Your city/town will have info on what is required in your area.

Proper bonding will keep all objects that you touch at the same voltage potential, preventing you from being shocked when in, or getting in and out of the pool.


TFP Expert
Apr 19, 2013
Sacramento, CA
You have to have rebar in the pool walls and that must be connected to the deck rebar/ mesh or #8 bonding line in the deck. You either need to get an electrician to help you with bonding or read Mike Holt on Pool bonding.


That is a PDF on Pool Electrical. Its based in the 2014 NEC Hawaii has adopted the 2008 NEC statewide but your county bay be different.

Also your drains must be hyrostatically balanced with approved drain covers. Not just pared but paired and balanced.

Hawaii requires a building permit for pools deeper than 24 inches. Do you have plans and a permit? We all complain about building inspectors but they can be very helpful to the dyi community.

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