Above ground pool inside a greenhouse

[Rayon]

I am in Ontario Canada with intentions of building and above ground swimming pool inside a greenhouse in the spring.
If anyone has tips for me would be appreciated.
One specific question that I have not been able to get answered yet is related to indoor saltwater chemistry. I have been snooping around this site for a bit and have not found any tfp type recommendations that apply to an indoor saltwater pool?

 

[JohnT]

Welcome to TFP!

A pool using an SWCG to chlorinate is just a chlorine pool. Your issue will be figuring out how much effect the UV light striking the pool has on chlorine. The glass or polycarbonate in your roof probably blocks some UV, but not all.

Indoors, we normally recommend 20-30ppm CYA and 4ppm FC. The CYA makes the water feel better to swimmers. Outdoors, your SWCG manufacturer likely tells you to maintain 70-80 ppm of CYA. You are in an unknown place somewhere between indoors and outdoors. I’d recommend you treat it as an indoor pool to start. Your SWCG percentage should be fine at a very low setting. If the unit has trouble maintaining chlorine, you may need to slowly increase the percentage and/or pump run time. You’ll also want to keep an eye on your CC, since it is broken down by UV light. If it creeps up, you may need a UV sanitizer to keep your water in good shape.

 

[Rayon]

Thank you, I have already found the numbers of 40 to 50 CYA for a chlorine pool and 70 to 80 for a saltwater. Indoor as you mentioned is listed as 20 to 30 but I assume that is for chlorine as I have been unable to find anything specific to indoor saltwater.
Your mentioned about cc is interesting as I had been considering a pool cover as it would be easy to do indoors but I'm currently of the opinion it is probably a bad idea to cover it given the fact that not only will my greenhouse reduce UV rays, it is also in the shade 3/4 of the day.

 

[ajw22]

Indoor as you mentioned is listed as 20 to 30 but I assume that is for chlorine as I have been unable to find anything specific to indoor saltwater.

Saltwater is just a chlorine pool where the chlorine is generated on site.

CYA level depends on whether Liquid Chlorine or SWG is being used or if it is outdoors or indoors.

Then FC target is based on CYA level...

The Free Chlorine and Cyanuric Acid Relationship

Managing your cyanuric acid and Free Chlorine levels is key to stabilizing your pool. Learn how these two items affect each other.

www.troublefreepool.com

 

[JoyfulNoise]

How will you manage the humidity? The indoor pool is going to generate a lot of humidity and it will be no fun swimming and sweating inside a greenhouse in the summer … it’ll basically be a sauna with a really warm pool of water. Indoor/outdoor air exchange can help a lot but that’s much harder to do in winter as cold outdoor air needs to be heated or else you cause a lot of condensation inside the green house. Plants might like it but most humans will find it pretty uncomfortable.

 

[Rayon]

How will you manage the humidity? The indoor pool is going to generate a lot of humidity and it will be no fun swimming and sweating inside a greenhouse in the summer … it’ll basically be a sauna with a really warm pool of water. Indoor/outdoor air exchange can help a lot but that’s much harder to do in winter as cold outdoor air needs to be heated or else you cause a lot of condensation inside the green house. Plants might like it but most humans will find it pretty uncomfortable.

It will be a greenhouse structure but there will be nothing in it except for the pool and it is going to be unheated. It is also in the shade after about 10:00 in the morning and the bottom four feet of both sides can be opened up and the top of both ends as well. Also I am in Northern Ontario where the biggest concern usually is getting a pool warm enough. I do not intend the greenhouse to be much of a season extension but rather it is to keep out leaves and for privacy. I do not think that humidity will be a problem to the structure itself and I was hoping that I have enough ventilation for it to be comfortable but I have been unable to find much useful information on this project so maybe it won't work as well as I am hoping.

 

[phonedave]

Thank you, I have already found the numbers of 40 to 50 CYA for a chlorine pool and 70 to 80 for a saltwater. Indoor as you mentioned is listed as 20 to 30 but I assume that is for chlorine as I have been unable to find anything specific to indoor saltwater.
Your mentioned about cc is interesting as I had been considering a pool cover as it would be easy to do indoors but I'm currently of the opinion it is probably a bad idea to cover it given the fact that not only will my greenhouse reduce UV rays, it is also in the shade 3/4 of the day.

CYA "protects" chlorine from the suns UV Rays.

It is lower (or zero) for indoor pools because they don't get UV rays from the sun.

It is lower for SWGC pools because when adding bleach or liquid chlorine, you add it all on one dose (or maybe two doses per day if you do that). It gets built up quickly, and then has to be protected as it goes down.

A SWGC generator generates chlorine over time, It may run for multiple hours, at multiple times per day. It is like adding liquid chlorine in small doses multiple times a day. You need less sun protection that way.

Your pool is going to be somewhere between indoor and outdoor. It is going to get some UV through the greenhouse glazing, but it will be less UV that it would be in the sun. Start with a low level of CYA, and then see how your SWGC does. If your CL drops too much between cycles, then boost the CYA a little.

It's not a difficult thing, it just requires a little bit of tweaking to get it dialed in.

All of these numbers are just estimates / starting points anyway. A pool in 14 hours of sun a day is going to burn off more chlorine than a pool in partial shade. Two 20,000 gallon pools are going to be different if their surface areas are different. The CYA amount that works for somebody who always uses a solar cover is going to be less that somebody with the exact same pool who does not.