Pool in a Tent...High Humidity, Gas Build-up...Help please.

[pbolden]

Hello Everyone,

I have a small inground fiberglass pool (9x18x4). To swim during the winter I enclosed the pool with a 10x20 polyethylene tent. The issues are a lack of ventilation and high humidity levels.

Because of the lack of adequate ventilation there is irritatingly high levels of fumes particularly after shocking. There are also high levels of condensation which have water dripping everywhere thus rust and mold are a concern.

Three Solutions as I see it. 1) Scrap the tent idea altogether. 2) Add vents to the ceiling and ground levels. 3) Add a high capacity dehumidifier (50 pt.) and vent the discharged air to the outside while returning the water to the pool.

Solution 3 is my preferred option. The high capacity dehumidifier is rated for 4,500 sq.ft. The tent is 200 sq. ft. or 2,000 cu.ft. and the ability to vent the exhaust outdoors should greatly reduce the build-up of gases in the air. As an FYI, I would disconnect the dehumidifier while people are swimming.

Any thoughts, ideas or additional solutions are GREATLY APPRECIATED! Thanks for your help.

[Denniswiseman]

I take it you heat your pool so the first thing I would suggest is you get a thermal cover for it
The second thing is fumes. You shouldn't have fumes unless you have a high concentration of chloramines
Let's have your numbers (CYA is very important as is Free chlorine and Total Chlorine)
FC:
TC:
pH:
TA:
CH:
CYA:
Thirdly just open the doors to let the saturated air out, ventilation works well for saturated air
I wouldn't bother with the dehumidifier apart from the cost and running costs but if you do you won't have to vent the treated air to the atmosphere as all the water would be extracted from it

[pbolden]

Hello Denniswiseman,

Thanks for the reply. Background: I am gone most of the Spring, Summer and Fall and the only chance for me to use the pool would be in the Winter. As a result the pool has been closed for a couple of years and I just opened it last week which is why the pool was shocked and the chlorine levels are so high. Technically, the pool is being opened and I am bringing the pool chemistry in line. Once that is accomplished I believe the out gassing will be with in tolerable levels (am I wrong)? For example, I keep the pool warm at about 86 degrees F so my target Chlorine level is 3.0 ppm. The pool is heated and I do have a thermal cover. Any further thoughts?

Thanks!

Current Stats:
TC 10.0 (after Shock)
FC 10.0 (after Shock)
PH 7.5
TA 70
TH 300
Stabilizer 20

[Denniswiseman]

Those numbers look OK
I was concerned that you had a lot of chloramines through excessive CYA. If you use Chlorine / CYA Chart and Recommended Pool Levels you will see that if you use stabilised chlorine your CYA increases and you need more chlorine
Sodium Hypochlorite or just plain bleach for your chlorine sanitation will only add salt

Excessive CYA renders your chlorine ineffective and you have to use more to get the same sanitation
For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm
To reduce your CYA you have to do a partial drain and refill
Continous use of Trichlor/Dichlor will raise your CYA which means you have to raise your chlorine level as well

One other point is you can swim up to SLAM level, which is where you are now