Gardens and Saltwater Pools

[Dirk]

Whether you use a salt water chlorine generator (SWG) or liquid chlorine (LC), all pools are, or become, saltwater pools eventually. SWG pools are based on it, LC pools acquire salt over time, as chlorine, muriatic acid and humans all leave salt behind (which never evaporates and builds up).

Salt leaves your pool in a number of ways, like when kids splash it out, or when it rains enough to push salt water out of your over-flow system, or if you exchange water, or backwash your sand filter, etc. But generally, it's always present in your pool.

So where does that water and salt go, when it splashes out or overflows? If it goes into your garden, plan accordingly. If you're designing a new pool and backyard landscaped oasis, don't forget about this issue. You can find plants that are OK with the level of salt in a swimming pool, but keep even those a decent distance from the water's edge. And you can send excess pool water to a "dumping ground," via proper drainage in your deck and a built-in overflow system. But you shouldn't rely on your street for this, as most municipalities don't want you to send pool water into their sewer systems, or gutters, because of where that salt ends up (like in a local stream or lake).

My city wants me to dump pool water into an open field. And I happen to have one behind my pool. I noticed this yesterday. It's been raining here pretty good, and my overflow system has been performing mini-water exchanges for me all winter. My salt and CH were all lower this Spring, which is great for maintaining my target chemical levels. CYA, too, but that's an easy fix. But even the rain-diluted excess pool water did this, just past where my overflow pipe exits, in a field of weeds that would otherwise survive just about anything.



I've always been concerned about what my pool water might do to a grove of trees behind me. But this "path" ends well short of the trees. The salt is still going to work its way down to them, I'm sure, but at least it's going to take a very long time, and by then may be diluted enough for the trees to withstand.

I'm just grateful whoever planned my landscaping and pool thought to (or was made to) include a good drainage system that ends well past my garden.

 

[Newdude]

IMO it's easy to drown plants and grass that are less hardy.

Plenty of people blame their non salt pool water too, and while the salinity may be higher than they think, it's still not high enough to matter.

 

[Dirk]

IMO it's easy to drown plants and grass that are less hardy.

Plenty of people blame their non salt pool water too, and while the salinity may be higher than they think, it's still not high enough to matter.

Agreed, and the garden surrounding my pool has been fine. But too much water wouldn't explain that dead zone path down below. Those weeds will, and do, grow in anything. Except salt.

 

[Newdude]

But too much water wouldn't explain that dead zone path down below.

Yes it would because the path stays wet or even submerged for long stretches during storms.

My grass is fine in a rain or pool puddle for days. I overwater my indoor plants by accident, actively trying not to, and the difference is one can handle the cold and one can't IMO.

 

[Dirk]

Yes it would

You can't see the angle from that shot. It's very steep, so water doesn't pool there. Yes, it would get more water than surrounding areas because of the drainage, but not like a swampy puddle in a lawn or an over-watered house plant. And I have other drains, coming off my roof, running through different areas of the same type of weeds, just a few feet from that salt path, with no bald spot like that. And there's more water coming off my roof than off my pool (sq.ft.-wise). It's gotta be the salt.

Agree to disagree.

Regardless, doesn't change my premise much. If you don't plan for your pool's runoff, your garden might suffer for it. Building inspectors and architects automatically consider roof and yard runoff, that's their job, but I bet it's common to overlook the pool runoff (splash out, overflow, backwashing, water exchanges, etc).

 

[Newdude]

Building inspectors and architects automatically consider roof and yard runoff, that's their job, but I bet it's common to overlook the pool runoff

It is sadly entirely up to the pool owner 9 times out of 10, who doesn't know much about anything during their first rodeo, also 9 out of 10 times.


Or even how the pool positioning affects the house runoff. My 1st pool changed the way my yard drained and flooded my house on year 3 when a big enough storm finally hit.

Much more thought went into pool #2.

 

[ArtP]

It is important to consider for some types of plants in particular. I'm growing tropical plants, and some of those are very sensitive to salt. Mangos, for example, can barely even handle the salinity in most tap water here in the Phoenix area. A lot of mango growers here use RO water or harvest rain water for their mango trees, because the salt coming from their hose or irrigation systems will cause leaf tip burn.

 

[Mdragger88]

I’m actively trying to kill the grass/weeds where my backwash goes and so far not much luck…
Plenty still coming up through the gravel.
I still have to get the roundup out on a regular basis.
Maybe these Mississippi weeds/grasses are tougher?

 

[ArtP]

Yeah, some plants are salt tolerant and others aren't. Before I switched to saltwater and a cartridge filter, I used to backwash onto my lawn (bermuda grass) and it never seemed to harm it.