does salt alone help fight algae

[lefty51]

Ok, I did a search for this answer, but probably missed it.

I was looking at homemade weed killing solutions and I noticed several times it was mentioned adding salt to "keep" the weeds from returning. It was stated "be careful where you spray" as the salt would keep anything from growing.

That's when the light went on ! :idea:

Does all the salt in my pool, waiting to become chlorine, have any algae killing ability ? In other words, let's say two pools one with salt and one without lose pumping ability, would the salt pool stand a better chance holding off algae then the one without ?

I'm thinking the salt on the ground from spraying "dries" out causing this effect, similar to what salt water splash out can do to pool surfaces.

Geez, did I just answer my own question again

 

[cowboycasey]

hmmm, dont know.. I can say that I had an algae breakout in my spa last year, bromine went to 0 and I missed it.. I had salt at about 2500ppm, no SWG at the time.. so it can happen and there are alot of people on here that have had outbreaks with a SWG in there pool when it dies, is not on enough or something like that..

 

[JVTrain]

No.

Algae is not like weeds. Two different environments. Water and soil. Salt in soil will prevent plant growth because it disrupts water uptake in soil based plants. More water is needed per plant to achieve the same amount of water uptake in the plant. High enough salt (salinity) in soil and plants simply can't get enough water to survive.

In a pool or the ocean (much higher salinity), the salt is dissolved in water. There's plenty of algae life in the ocean right? Unless you get to something along the lines of Dead Sea salinity where there just aren't algae that I've heard of that are evolved or adapted for that environment, you'll not notice the difference for algae prevention. Depending on the species of algae, it may actually prefer slightly salty water and grow faster than low/no salinity water.

 

[lefty51]

That's the first thing I thought of was, there is algae in the ocean. But thank you, that makes sense, water intake.

It's one of those things I didn't think would work, but was not smart enough to know the answer. Kinda like I KNOW how an atom bomb works, but can't explain WHY it works.

It's so nice to have all this brain power and knowledge at my disposal . Thank you !

- - - Updated - - -

P.S. just curious, does the salt absorb the water, robbing from plants or just keep the plant from absorbing it ?

 

[chem geek]

There are different types of algae and some freshwater algae may not grow as well at higher salt levels, but as was pointed out there are other algae that grow better in higher salt levels.

While it's possible that the higher salt levels in a saltwater chlorine generator (SWCG) pool may somewhat inhibit some freshwater algae, the difference is fairly small. We do have a somewhat lower minimum FC/CYA target of 5% for SWCG pools compared to 7.5% for non-SWCG pools but there's more going on than just salt. There's also superchlorination in the SWCG cell (high chlorine at low pH near the chlorine generation plate) which may kill at least free-floating algae that gets circulated and there's more regular automated dosing for more consistent chlorine levels. We've tried to tease out the differences between pools that have high salt but no SWCG and pools that have automated systems (peristaltic pumps or The Liquidator) but the differences are too subtle to be definitive though it does appear that the automation alone isn't enough to get to 5% under any algae nutrient levels (e.g. phosphates, nitrates).

If one wanted to do something to their bulk pool water to inhibit algae growth besides maintaining a minimum FC/CYA level which makes such techniques unnecessary, then the use of algaecide (e.g. Polyquat 60) or a phosphate remover would have the most effect while using 50 ppm Borates would have a lesser effect and I would expect that having a higher salt level would have the least effect.

 

[lefty51]

Thank you Richard, I think you knew where I was angling with this. Even with a salt pool, I still have green swamp when I open in the spring. Having been on here I realize I can mitigate a lot of it by WHEN I close the pool and WHEN I open it.

I want to try to get the right "mix" when I close closer to 60 degrees, with my mesh winter cover, so spring startup is a quicker process. With our sometimes warm Dec. -Jan. , it will probably be a battle.

But, with the vast knowledge on here and your willingness to gladly share it, I'm still ahead of the game. Again thanks you guys