Pool for the deployed troops

[sandstormoasis]

I'm not sure if this is the correct place to put this post, but I have to start somewhere. I am currently deployed overseas and our location has a empty concrete pool of which we are looking to get back in operation. Leadership here is excited to get this project moving, but I need to come up with a cost estimate to get it up to speed.

The pool is 60' x 40' x 5.5'. I est. ~ 100K gallons. All the equipment has been torn out and is gone, so we need the filtration system from the ground up. All the installation will be done ourselves (plenty of competent folks to do it). Here are the questions I have:

1) There are 4 x skimmers, and 4 x return lines. Looking through the flow rate calculator, I think I need a pump capable of > 166GPM using a 10 hr turnover. What size pump do I need for this?

2) With the above information, what size filter? Would a 36" sand filter be adequate?

3) The pool is rough concrete. There is no requirement for any of it to be pretty, just functional. There are several cracks along the bottom that allows seepage INTO the pool. I'm assuming to fix these we will need to chisel out the cracks and refill to seal them. What is the recommended material for this?

4) The rough concrete needs to be painted. Would a cheaper acrylic pool paint be sufficient considering the longevity of our possible occupation? Or would it be better to splurge on epoxy paint from the get go? We do have industrial epoxy paint they use on the auto shop floors. Are they created equal?

5) Chlorine vs salt vs whatever. I'm only familiar with chlorine pools. All the rave seems to be with salt pools now days. What is the initial cost and continuing maintenance cost difference? Contrary to popular belief, there is not an abundance of money to spend on 'moral' projects.

I'm sure there are other questions that I can't think to ask at the moment. Please send any and all recommendations to me.

I hope there is someone here that can help with my questions or at least direct me to someone who can. I appreciate your time. If we can pull this off, there will be a multitude of troops who will benefit from the effort!

In your service,
Robby

[CarlD]

Robby,

You have a lot of great questions and I'm sure EVERYONE here will do everything they can to give you the best advice they can. I can only talk about a few things--what I know about.

I'd estimate your volume at just under 90,000 gallons figuring that with a 5.5' depth you only actually have 5' of water.

I would guess--and it's STRICTLY a WAG, that you'd need two 300lb sand filters (I can never keep straight the " to lb conversion) and two 2hp full-rated pumps--one for each filter. But that's just my WAG. Better people than me can give you better recs.

I'm not sure how to repair the pool. You may be able to chisel out the crack and fill it with pool epoxy--you are painting over it. I can't help you on the paint questions.

As for Salt Water Generation vs chlorine. BOTH are chlorine pools. Salt is Sodium Chloride and the system cracks the salt to create free chlorine in lower, but very constant levels. Not sure of the chemistry, but the combined chlorine (the used-up stuff) recombines with sodium to make salt. In THEORY, your salt level stays the same.

However, these systems are pretty expensive considering how big your pool is--about 4-6 times the size of most of our owners' pools, and double the very biggest. (My own is about 20,000 gallons).

But you should have plenty of access to liquid chlorine over there. LC is just like bleach only about twice as strong. It's usually rated at 12% but when I test it it's usually more like 14-14.5%. What this means is that you'd need about 9 gallons of ordinary regular laundry bleach (no sudsing, gel, or perfumes) to get a free chlorine level of 5.25 parts per million 9 gallons of Ultra bleach would get you a level of 6ppm--generally good, clean water. But you could get the same level from 4 to 4.5 gallons of LC, and it's sold in 5 gallon carboys most places.

A 5 gallon drum here is now between $18 and $20, so how many gallons would a properly sized SWG system cost you? Say it's $4000--that's 200 5-gallon carboys of LC. Say you use a carboy a week (reasonable, once you have regular maintenance going). If your location is in one of the two hot zones our nation is now engaged in, you probably have winter time and can swim for, say, 4-5 months a year. So...say it's 25 weeks/year. That means your 200 carboys may last 8 years. In other words, by MY very, very rough estimate, it's going to take years to re-coup the cost of the SWG. I'm guessing about a lot of these numbers, and the amount of usage can vary (Make sure NOBODY swims without showering first and your chlorine will last a lot longer). But it's a ball-park guess.

Again, others will surely weigh in to improve on my estimates, but I'm pretty good at rule-of-thumb calculations on chlorine:

1 gallon of 5.25% bleach will create 5.25 ppm of chlorine in 10,000 gallons of water.
1 gallon of 6% ultra bleach will create 6ppm in 10,000 gallons.

You need 2 gallons of either to create the same level in 20,000 gallons.

And you'll need 9 gallons to create the same level in 90,000 gallons.

Since LC is about twice as strong as Ultra bleach, you'll need half as much.

Good Luck and thank you for your service to all of us.

Carl

[sandstormoasis]

Thanks Carl for the reply.
I do believe the traditional chlorine option is going to be the best option not only due to price concerns, but for the pure simplicity. I'm comfortable in maintaining a pool, but when I'm gone, I want it to be simple for the next guy. I didn't think of liquid chlorine as the sole chlorine used. I was thinking traditional chlorinator via tablets. Considering my location and the probability of buying chlorine in bulk, doesn't LC gas off at a high rate? Would I be able to use up a drum before it went bad? Some good thoughts!

You think 2x 300lb filters would be sufficient? This will be a high use pool. Something that just came to mind... Will a sand filter be capable in filtering out 'desert' dust?

Another question: What's the best way to minimize evaporation? It will probably be a daylight use only pool. Rolling plastic over it at night maybe?

Please keep the replies coming in! I (and everyone else that will be able to use it) truly appreciate your time!

Robby

[aylad]

While using a chlorinator with tabs in your situation is probably ideal while the stabilizer is building up, the problem with the chlorinator and tablets is that, eventually, your stabilizer level is going to get too high to be able to keep the pool clear. Once it gets to 80 ppm or so, you're going to have to switch either to granulated chlorine (cal-hypo) or liquid chlorine. Depending on how long your swim season is, with it being a high use pool, and with the amount of heat/sunlight the pool gets, I would think you would be able to use most if not all of a drum of LQ within one swim season. Due to the sheer volume of water, each chlorine dose is going to be larger than it is in the average pool, and I would think that it would need to be shocked frequently, which is also going to take large amounts of chlorine at once--to me, the drum makes the most sense. Plus, once you work out what the nightly dose is, you just tell the next guy how much to pour in each night.

Not sure where you are--I have a cousin finishing up his second tour in Iraq this month and we're looking forward to getting him home. Thank you so much for all you are doing for us back here!!!

Janet

[waste]

#1 - THANK YOU FOR YOUR SERVICE TO OUR COUNTRY/ THE WORLD!!


#2 - Welcome to the forum!!



55 gal drums would be a less expensive chlorine source but, keep them cool and in the shade! LC breaks down more quickly with UV exposure and higher temps and the higher the %, the more quickly it looses it's potency. (you might want to incorporate a below floor level hole to hold the tank(s), kind of like how we used to bury beer kegs on the beach to keep them cold all day ).

Covering the pool when not in use is always a good idea - any tarp would work and having 2 people 'fan' or 'sailor' fold the cover every morning makes putting it on and taking it back off a ~3 minute project

I'd use Waterplug TM to fill the cracks (follow the directions on the can to prepare and apply it- or I'll gladly give you advice).

I wouldn't bother with getting the best paint. The difference, that I've seen/ know about, isn't great enough to make the cost worth it, IMHO. Best bet is to get a paint that can be applied with some moisture remaining on the surface (which top quality epoxy paints can't).

Pump and filter sizing is a question best left to someone else, but I'd suggest at least 2 600 lb sand filters, plumbed in series.

This brings us to chlorine delivery - with the bather load and blown in debris you'll expect, your frequency of backwashing might well allow the use of a BIG tri-chlor feeder (again, I'm not the expert here on this stuff) A peristaltic pump might be the optimal way to introduce the LC to the pool, augmented by manual dosing.

i want to see your pool become a reality and will help as I can.

Please send my regards to all who are with you overseas!!

Luv & Luk!

Ted

[CarlD]

One more thing:

You are going to need at least one good FAS-DPD test kit and don't allow ANYONE to use it who isn't trained on it. It's easy to do, but easy to screw up. Regular testing will save you a fortune on chemicals, prevent a nightmare of problems, and keep your pool up and running.

Pool Forum is just the place to learn the correct chemical maintenance. We have a number of stickied thread on just that but it's all really simple--once you understand the trick.

It's all about chlorine levels and pH levels. BUT there are monkey wrenches thrown in.
Stabilizer changes the ideal chlorine levels.
Total Alkalinity is closely connected to the pH.
Calcium hardness helps protect concrete pools, but is useless in vinyl.

But reading is free!

I would rate Ted's guess of two 600lb sand filters probably better than mine of two 300 pounders--Waste is better on that stuff than me by a long shot.