care for (sorta) indoor pool help

[scheckaet]

I might be buying a house with in-ground pool that's enclosed in what i call a "green house structure"
here is what i know from what i saw:

location: Oklahoma city
concrete pool built between 1956 (year the house was built) and 1980 (year the pool enclosure was installed)
capacity? over 12,000 gallons (don't have the dimensions yet)
sand filter
pool enclosure: 1780 ft2 green house like structure with 6 top panels that can slide out.


I currently have an intex above ground pool 16x32 with swg and I'm familiar with how to take care of it. However, i know indoor are a bit of a different challenge because of UV and humidity levels etc...

1: can it be converted to a swg system? I'm afraid the salt would eat the concrete and the structure.

2: because of the type of roof structure (plastic like roof panels) should I worry about getting enough UV light? in other words, should I treat this pool the same way as my above ground in regards to cya levels, chlorine...or do i need another source of UV?

3: we are planning on using the pool year long for a small swim school (or as much as possible, there might be a point were the cost of keeping the place warm will be way more than the $ generated by the business)

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[scheckaet]

plan:
add a pool heater
add a pool blanket with reel to reduce heat loss at night and reduce humidity
repair / replace the gas powered space heater that is already there (most likely not working)
With both I am hoping it will be enough to keep the place warm in the colder month. We may need to close business in the very cold month (freezing temp).
this is obviously not air tight so I don't know how well I'll be able to keep the place warm enough. I will go through and close as much as the gap as possible.

Some type of alarm on all doors (got 2 kids under 2) and and 2nd pool enclosure like a pool fence Removable Mesh Safety Fence Products | Protect-A-Child

Do you all think i will need a dryotron or similar to keep humidity level in check and keeping the main house from falling apart?
Any challenge with this type of structure?
Is this unrealistic to heat the place up with this type of enclosure?

I'm still going thru this website trying to answer some of these questions but I'm looking for as much input as possible.

thanks

will

 

[Isaac-1]

Ok I will give it a shot, as you know from our PM's I have an indoor pool, and I think you have seen the skylight situation I have with an approx 6x40 ft skylight section that runs along the apex of the roof over the pool. Mine is currently made from polycarbonate, but originally was a clear plexiglass similar to what you show above. My pool is also surrounded by sliding glass doors. Each of these materials transmit differing amounts of UV light as well as different parts of the UV spectrum, so it is hard to say what your full coverage of what appears to be fiberglass reinforced plexi will do (it is hard to tell aged plain flexi from fiberglass reinforced plexi in photos once it ages).

I can say this though, with my pool supplemental oxidation is only needed after large swim parties otherwise I get enough UV to keep CC levels down when it is just the family or small groups swimming, this is all about bather volume to pool size though. I did buy a UV ozonator off ebay cheap a few years ago, and this is such a non problem I have never bothered hooking it up. Instead I just use some MPS chlorine free shock after the occasional large swim party (typically a couple of times per year), the down side to MPS is that it shows up as CC on the standard chorline test, Taylor does make a special MPS test to eliminate this confusion though which I do have, but don't usually use unless my CC readings after using MPS are outside the expected range, or last longer than expected.

Personally I would skip the SWG, I use a chlorine injection pump system, as corrosion is already enough of a problem around an indoor pool even without the salt. (interior corrosion was the main reason for my roof replacement a couple of years ago as after 30+ years the purlins that supported the roof had corroded away to nothing in places and there was real concern about roof collapse.

One more thing about skylights like you show and a heated pool in the winter time, when the air temperature outside gets cold those uninsulated skylights will get cold, the humidity from the pool will rise and collect as condensation on exposed metal and on the skylight, this will form droplets and rain down to those below. I can attest that nothing distracts from being relaxed in a warm pool like an ice cold rain drop down the back, thankfully the rain zone in my pool only covers about 1/4 of the width.

As to chemicals levels I keep my CYA between 20-30 ppm, usually closer to 20 and dose FC accordingly based on the CYA/FC chart.

A "solar" cover will make a huge difference in humidity around the pool, I added one a couple of years ago for the off season, I only have solar heat at this time which keeps the pool warm until around the first freeze of the year (originally the pool had electric heat also, but was not worth the cost to maintain a warm pool at least not for us, particularly during the busy holiday season)

I can't really comment on humidity control otherwise, I use high volume exhaust fans which work fine during the warmer months, simply by turning them on 10 minutes before going for a swim (I did the math when I had them installed with the new roof, on high each one can change out 100% of the air volume in the pool house 4 times per hour), also my indoor pool is not attached the the main house, instead it is about 40 feet away in a separate building.

 

[scheckaet]

thanks for the reply, funny thing it took a few weeks before i realized I had a PM.
The numbers you gave me confirmed what i feared, building a fully enclosed pool is not going to happen for a long time.

In any event, this is as good as i think we'll ever get for what we can afford so we made an offer and unless something really bad shows during the inspection, looks like we are going to dive in head first (pun intended ) into this new enterprise...

On the SWG, I like the ease of use but i wasn't too excited about adding another corrosive element to this indoor system...so that's out. I'll just add a automatic chlorine feeder.
I never thought about the temperature difference in/out that would create a lot of condensation. so that might be an issue. I'm hoping it won't rain inside and just slowly go down the slope of the roof. I have the feeling that even if I install a dryotron or similar, because nothing is insulated I'll get a lot of condensation. Need to do some more research on how they work and what are their limits.

From the little research I've done so far on solar cover looks like the consensus is buy a cheapo, they last just as long as the expensive ones. Hopefully this will limit the evaporation and heat loss year long.

I don't know how much UV i'll get in especially in the cold months, so i'll have to get my hand on some MPS till i figure out if this is enough or if I need a 2nd source of oxidation.

I am going to try and power wash the roof panel, and hope to get a "cleaner" look and a little more light in.

I'm sure I'll have more questions in the next few weeks / months.
Thanks

 

[chem geek]

You could add a UV system as that can be helpful for indoor pools to control chloramines if the UV system is sized large enough. The downside is that it can increase chlorine demand but if you are able to tune its ontime then you can balance it out for controlling chloramines without lowering FC by too much. Of course, if you are able to get some amount of direct sunlight (particularly UV) on the pool, then that might be enough.

 

[COBrien]

I can't offer any advice on this issue, as I have an outdoor pool...

But I will say, if you find yourself needing any help with this project, feel free to PM me -- I'm just 45 minutes away.

 

[scheckaet]

I've been thinking more about the "indoor" issue. Here is what i understand:

humidity = bad because:
-high humidity (above 50%?) will destroy your enclosure (corrosion, rot...)
-promotes mold growth
-comfort level inside enclosure, health issue
-Am I missing anything?

Here is my situation, the enclosure is linked to the house on one side and is only made of plastic and aluminum (as far as I know).
1-With that being said, i wouldn't think the wall of the house could not take the humidity any more than if it was "open" to the sky and the elements, like any other wall of the house. So I don't foresee any issue on that mater. Unless the CONSTANT humidity IS the problem?

2-with no real substrate (organic materials) to grow on, i don't see how mold could actively grow and become an issue.

3-I assume the potential health problems linked to indoor pool are 2 parts: comfort level associated with high humidity and potential outgas from the pool chemicals as well as "bad smell". Renewing the air in the enclosure should solve that problem right? Using 2 sets of fans (in and out), I should be able to bring those level down (at the cost of more energy bill in natural gas and electric to heat the place back up...) I'll have to figure out how big of a fan, how long to run them and how much air needs to be renewed.

The ideal would be a BIG dehumidifier made for pool (2-4k?) like this: Ebac 190 Pint Indoor Pool and Spa Dehumidifier - PD200
, this might not be in the works this year. That's why I'm considering the dual fan system.

Also, the doors to the main house are not going to stay open for very long between clients so I don't see it being an issue. Even if it is significant enough, the "waiting" room can be somewhat isolated from the rest of the house.
If it is a issue, would a "cheapo" ($200-400) dehumidifier installed in this waiting area save the main house from falling apart and solve the issue?

Am I missing something?

thanks

 

[scheckaet]

to keep the humidity in check, I was thinking about using 2 fans (in and out) on opposite sides of the enclosure then wire them to a humidity sensor like this:
http://www.leviton.com/OA_HTML/SectionDisplay.jsp?section=62681&minisite=10251.
It seem you can adjust the % humidity it would trigger the fans and the length of time the fans would be on. (20, 30 40 min...) so that should work pretty well i think. You can also set it to run every so often, might be better that way to reduce the temperature fluctuation if it runs a long time.
I'll probably use something similar with a thermostat for the air temp (if i can fix the old unit...) and make sure they don't run at the same time.

 

[tim5055]

I only want to caution your that when you talk about running a "swim school" your residential pool may become a commercial pool. Many states have specific regulations on how a commercial pool needs to be cared for including inspections, type of chlorination and even if you can use CYA.

Check your states statutes so you know the regulations before an inspector knocks o my our door.

 

[smackdab]

Are you all saying that an indoor pool is not recommended to use a SWG system because of extra humidity and corrosion concerns or what?

I only ask because I see nothing here about using an SWG indoors and also it is not clear here what an indoor pool with a SWG cyas level should be (20 or 80 ppm).

 

[Isaac-1]

On some of those practical notes, I would tend to say humidity does not become much of an issue until it gets over about 80%, I think generally the fans are a good idea to remove humidity as this is what I do. I would not automate them based on humidity though, perhaps on thermostat for heat removal (how mine are set up). For humidity, particularly in the spring and fall, I keep things closed up to retain heat then run the fans for a few minutes to flush in fresh air just prior to swimming, the advantage to this is the pool and its surroundings (floor, walls, furniture, etc) still retain heat so the fresh cooler air does not feel so cool. If the pool is properly balanced there should be no problem with fumes, smells, etc. this is a common misconception people have from dealing with the typical high bather load poorly managed indoor pools with no fresh air ventilation so common in motels in many parts of the country. Long term exposure to high humidity does cause with electric switches, outlets, and type of appliance, so some thought must be given to this, for example as part of my re-roofing project a couple of years ago, I changed out a number of older florescent light fixtures (indirect lighting around the wooden trough around the pool above the doors) with modern wet environment sealed plastic fixtures (IP63 rated I think / spraying water rated, commonly used in parking structures, etc). I have never had a mold issue with my pool, but most materials were selected for the condition, all the wood work is made from pecky cypress siding which is a highly water resistant wood.

 

[chem geek]

An SWG indoors would use the same CYA level as non-SWG, namely 20-30 ppm CYA. The reason for the higher CYA for SWG pools outdoors is to reduce losses from sunlight. That is not an issue for indoor pools. The FC level for indoor pools usually has a higher FC/CYA ratio to help with oxidation so perhaps you'd run at 10% FC/CYA ratio though you can see how it goes. We don't get enough indoor pools reporting in to be as definitive as with outdoor pools.

With regard to corrosion issues, I don't think the SWG higher salt levels is worse for indoor pools than outdoors. We've seen salt splash-out issues onto aluminum automatic cover tracks (see this post), but that could happen just as easily outdoors if there were no rain to wash away the salt.

 

[Isaac-1]

I would have concerns about excess corrosion in any environment with higher than normal salt levels. At work we have a small fleet of delivery trucks that are mostly around 15 years old. All are the same brand, but some have longer enclosed beds on them etc. One of the trucks (a 2001 model) the one with the shortest bed on it (18 ft others are 23-25 ft) makes a weekly delivery run down to the coastal area here in SW Louisiana, it is the only one that routinely gets within about 35 miles of the coast (mostly marsh land), also even though it is not the oldest truck (some are 1999 models) it is at the point of needing to be replaced due to corrosion, door bottoms are rusted out, cab floor has holes in it, etc. While the other trucks are also showing their age NONE of them have any significant corrosion problems. While I know sea air has much higher salt levels, but if 4-5 hours exposure once per week can do this to a truck, 24x7 exposure around a pool can't be good either.

 

[scheckaet]

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I only want to caution your that when you talk about running a "swim school" your residential pool may become a commercial pool. Many states have specific regulations on how a commercial pool needs to be cared for including inspections, type of chlorination and even if you can use CYA.

Check your states statutes so you know the regulations before an inspector knocks o my our door.

good point, my wife was already looking into this.
Still looking to confirm from several sources though.

 

[scheckaet]

On some of those practical notes, I would tend to say humidity does not become much of an issue until it gets over about 80%, I think generally the fans are a good idea to remove humidity as this is what I do. I would not automate them based on humidity though, perhaps on thermostat for heat removal (how mine are set up). For humidity, particularly in the spring and fall, I keep things closed up to retain heat then run the fans for a few minutes to flush in fresh air just prior to swimming, the advantage to this is the pool and its surroundings (floor, walls, furniture, etc) still retain heat so the fresh cooler air does not feel so cool. If the pool is properly balanced there should be no problem with fumes, smells, etc. this is a common misconception people have from dealing with the typical high bather load poorly managed indoor pools with no fresh air ventilation so common in motels in many parts of the country. Long term exposure to high humidity does cause with electric switches, outlets, and type of appliance, so some thought must be given to this, for example as part of my re-roofing project a couple of years ago, I changed out a number of older florescent light fixtures (indirect lighting around the wooden trough around the pool above the doors) with modern wet environment sealed plastic fixtures (IP63 rated I think / spraying water rated, commonly used in parking structures, etc). I have never had a mold issue with my pool, but most materials were selected for the condition, all the wood work is made from pecky cypress siding which is a highly water resistant wood.

I am venturing into the unknown for the indoor care.
I hear you though, it might be overkill (and i hope it is). On the other hand, i have no idea how fast humidity will rise, so having the option to set and forget is great. (plus this is kinda fun to me to tinker with stuff like that)
I also like the fact that I can manually override for a set amount of time if they don’t work properly (these are designed for small indoor bathroom after all).

Having the fans (in and out) on a plain timer might actually work better in the winter months. Running for shorter time to reduce humidity should minimize the fluctuation in temperature and keep swimmer happier. (plus I would not need to get up at the crack of dawn to turn it on before the 1st swimmers show up)

I was also thinking about installing a thermostat to help in the summer months if needed. Keeping everything opened, roof panels and side doors, should be enough and I’m not worried about losing heat when it’s 90 at night.

How big of a fan do you have? How long does it take you to remove the humidity in the cooler months? Size of your enclosure seems smaller than mine but that’d give me good idea of what to expect.

I’ll probably have a console with the humidity controller + thermostat + plain timer so I can choose how to control the fan depending on how well the system work, the season…
So far everything I saw was for outdoor use. If not or too old, it’ll replaced with sealed units like you were talking about. I’d rather be safe than sorry! (I don’t like to mess with electricity, and even less when there is water close by!)

 

[scheckaet]

As for the swg, I kinda gave up on it, it's great for my above ground outdoor, but I really don't want to add any more corrosive element to the enclosure so I'll probably use liquid chlorine.
I was leaning on the Pool Liquidator for its simplicity of use but I think i'll go the stenner pump way, probably the 10 gpd (run less / cycle=longer life) single speed (less maintenance). Seems it gives me more freedom on how to adjust it compared to the liquidator with less refill/maintenance.

 

[Isaac-1]

I don't recall the exact model of fans that I have, but it is something similar to this one, but with a dial type thermostat mounted on them (I have a pair of fans, I think 18- 20 inch, leaning towards saying 18 inch high speed ) Canarm Wall Exhaust Fan F2 | Enclosed Exhaust Fans| Northern Tool + Equipment. As I recall I paid right at $900 for both fans. Thermostats stay pre set to turn on around 82 degrees, but are wired into a light switch that way I can turn them off completely to let temperature build up in the day for that warm day, cool night time of the year. The main pool building is just under 40x60 on the interior side walls are about 14 ft with roof peak at about 17.5 ft, there is also probably another 300 sq ft with 8 ft ceilings in the kitchen, bathroom, etc that is open to the pool. With the fans running on a typical autumn evening they exhaust the heat and humidity from the air in about 10 minutes.

If you opt for a Stenner pump, remember indoor pools tend to consume MUCH less chlorine than outdoor pools so size accordingly, for my pool even in the peak of summer I typically use less than 1/3 a gallon of 8.25% bleach per day, most of the swim season it is closer to a quart per day.

Ike

p.s. I estimate based on typical TFP user bleach consumption for similar sized outdoor pools, over the life of the pool something close to $30,000 has been saved on bleach (based on current bleach prices), this make the money I spent on a new roof a couple of years ago much more acceptable

 

[scheckaet]

we are getting close to closing on the house (pun intended )
we have one little snag. The pool inspector said the it needed re-plaster or epoxy.
When he brushed the pool you could see white chalky dust coming off the wall.
The pool appears to be 16x36 (measured) 40 inches to 8'3 deep (guestimated)
The guy quoted me 4k to epoxy it (10 years "longevity") and 7k for re-plaster (15 years "longevity")
Does this pricing sound right?
10 years out of epoxy and 15 out of plaster sounds a bit off from my reading. I thought it was more like 5 years out of epoxy (maybe) and 10-12 out of plaster.
thoughts?
Now i need to make a decision re-plaster or epoxy???

 

[scheckaet]

Forgot to mention he said paint is less porous and would have less algea growin on wall than plaster...sigh.

 

[jblizzle]

I would not epoxy. If the plaster is at the end of its life, it is likely rough and chipped. Just throwing some paint/epoxy on it will not hide the imperfections, it will just make them all the same color. And based on reports, the epoxy does not last anywhere near 10 years. Go for new plaster ... and it it can last a LONG time if you properly maintain the chemistry.

If you maintain the chlorine, you will not have algae, regardless of the surface.

Finally, I would get into the house and live with the pool for a year and see how bad the plaster really is. The dust could clear up with a few brushings and be fine for awhile. If the pool is not losing water, then the plaster is fine ... may not look perfect, but it is doing its job.