Anyone Ever Lower CYA Slowly Via Irrigation?

[Surf Hawk]

I have high CYA in a drought area with temporary bans on draining pools and temporary high rates above 12,000 gallons/month. I am considering lowering my CYA by using pool water to irrigate my yard. Takes a long time and uses more water, but hopefully no net extra consumption.

To test this idea I shut off my irrigation and this weekend watered via the waste on my multi-port. My watering lowered my pool 3" which was 1,500 gallons or a 5% drain. With my CYA of 160 it would take me 27 weekends using this method to get to a CYA of 40. That is 40,000 gallons over 6 months (probably longer since if we get any rain this winter I wouldn't water). By comparison, should the city not punish me, a one time 75% drain of 20,000 gallons would cost $360. Of course most of this would go down the drain as I only need 1,500 gallons a week to irrigate.

I found a lot posts from people in my same situation in the past. Has anyone ever gone the route I am proposing, and if so were you happy with your choice or did you wish you just bit the bullet and did the one time drain? To do a drain over 1/3 I would need to have a "pool professional" sign off on a form saying I have an urgent need to drain. Not sure I could get a PB to care enough about my high CYA to sign that form.

My chart on how long consecutive 5% drains would take to get to a CYA of 40.

Week	CYA
0	160
1	152
2	144
3	137
4	130
5	124
6	118
7	112
8	106
9	101
10	96
11	91
12	86
13	82
14	78
15	74
16	70
17	67
18	64
19	60
20	57
21	54
22	52
23	49
24	47
25	44
26	42
27	40

 

[JasonLion]

This can work very well in a rainy climate, is not a good idea in an arid climate. Pool water contains a range of chemicals. In arid climates they can build up in the soil over time and eventually cause problems. In rainy climates they get washed out fairly well and there are hardly ever problems.

 

[timerguy]

That system of 5% at a time over 27 weeks will use over 28, 000 gals of water whereas 2/50% processes will get you about the same resulting cya, but only use 21, 000 gals of water. I'd bite the bullet to save over 7000 gals of water. Unfortunately, I had to drain 33% of my pool at a time 5 times to protect my liner. You can be glad you don't have to go through that! But, you will need a lot more bleach to keep your FC up too! That said, I don't irrigate my lawn much. Trade offs every way you can look at it.

 

[mrcarcrazy]

Personally I'd try to get a signature...

 

[Surf Hawk]

Thanks for the replies, everything pointing towards biting the bullet and I'm just fishing for someone to say the opposite. Maybe I can do a major drain the day before our next meter read and split the filling before and after the reading. Don't want some nosy city official up in my business.

 

[Wildcat]

Consider going to 60-70 CYA. In a sunny climate,IMHO,it may save some bleach each week and as long as you maintain minimum FC it can work. See how it works and if not to your liking and you still need to get to 40 CYA, do it over a couple of years. Hopefully it will rain more soon in the Southwest.

It seems that many proposing 40 CYA do not live in our very sunny, very dry climate. I have gone from 150+ CYA over the last 13 months while going bleach to 80 CYA, no problems.

 

[Richard320]

I've been doing it for a couple years to lower CH with no problem.

 

[ranger_ric]

I would smile and then have my gorgeous wife smile at a pool builder and offer him $40 and see if that would get me a waiver. it is a small world...

 

[Surf Hawk]

I have gone from 150+ CYA over the last 13 months while going bleach to 80 CYA, no problems.

Did you go from 150 to 80 just by not using pucks anymore and it drifting down, or have you been replacing water?

The good news is I think the previous owner was wrong when he told me the pool was 27,000 gallons. I just roughed in the numbers in my CAD program and came up with closer to 23,750 gallons and that doesn't include some extreme radii in the corners and bottom. I have to take some better measurements on where the deep end starts but if this is true I'd be replacing 6.3% which would cut it to 21 weeks to get to a CYA of 40 or 15 weeks to a CYA of 60.

 

[Surf Hawk]

Just to follow up on this, despite advice to bite the bullet and drain and fill, I decided to replace it slowly over time, mostly using rainwater harvested from the roof. For a few months I did irrigate my backyard with pool water then re-fill the pool with city water. Then the city raised rates again and put Stage 3 drought restrictions on, so I decided to focus on harvesting any rainwater that did come.

I hooked up my roof downspouts to drain into my pool and during a few storms would drain to waste about 6" of pool water and replace with rainwater. I think for every inch of rain I was getting about 2.5" into the pool. We got 11" in 2015 so I may have added 25" of water to the pool.

Now, 18 months later I am down to a CYA of 60 (from 160) without doing a drain. It took a long time, and I'll probably let CYA get to 50 or so, but I'm finally close. We also have very hard water so I think the rainwater addition will be nicer in the long run vs filling from city water.

Thanks for all the advice, and for anyone doing a search, consider harvesting rainwater. Even in a drought, a few 2-3" storms can help out.

 

[Patrick_B]

Thanks for the update, and glad you made some progress!

 

[Surf Hawk]

I kind of stopped checking my CYA once I got to 50, and now after a few months of keeping the pool very warm and a lot of kids splashing about, I just checked it this weekend and my CYA was near zero. I can't believe I actually have to add CYA after working so hard to lower it.

My R-0013 is pretty new and doesn't expire for over a year so I think it's good, although I do keep it and my TFT-100 kit in the shed with the pool equipment and chemicals.

I guess if this is true I can live the life of luxury for a few months with some pucks, despite considering them the devil since being enlightened by TFP.

 

[duraleigh]

I am so glad to see you watching your pool and managing it properly.

I hope you would take that test kit out of the shed and into the air conditioned house. You can test inside in comfort and you reagents will last much longer.