# Salt, how does it affect plants/algae?



## anonapersona (Oct 19, 2002)

In a pond forum I read of a study done by a pond plant seller (Bonnie's Plants I think) who had done a study with pond plants and salt. They found that 0.2% was lethal to floaters, like duckweed and water lettuce and hyacinths, and 0.3% was the limit for most other pond plants. Now, many of the pond plants are also used as submerged plants, to some degree, and the 0.3% was pretty much across the board of platns tested, so this 0.3% might be considered a limit. That would be 2 and 3 teaspoons per gallon according to my notes on salt in ponds, but this should be checked out with other sources. It's been a year since I read that and this info on those tests is from memory, not notes.

Now, I don't know if any other salts that we may be adding to the pond in the form of fertilizers need to be considered. But even so 2 to 3 teaspoons per gallon is a lot of salt. 

You might try to find Bonnie's Plants online and see if that is the location of that testing.


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## _~King~_~Tiger~_ (May 11, 2003)

Thanks anonapersona.  

So does that mean that the 1 tablespoon per 10 Gallon (approx 1/3 teaspoon per gallon) would hinder the plants growth? or not?

...and would it affect algae growth? :?


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## anonapersona (Oct 19, 2002)

My notes to myself (hope this is correct) that 0.1% salt ~ 1 teaspoon per gallon. So 0.33 teaspoons per gallon would be .033% salt which is well below the point at which the test cited mentioned observing problems in the pond plants. I have no idea if any meaningful difference between the pond and aquarium exists, but I doubt there is any. I do wonder if the ppm of various salts that we add in the form of fertilizers would add to that number, 1 ppm would be 0.0001% so the various things we add at 5 and 10 and 30 ppm shouldn't add too much to the total salt load....(someone who actually knows about this is welcome to join in and set me straight here if I'm all wrong)

As for inhibiting algae, I have no idea, I suspect that the sort of algae might subtly shift from one sort to another. I recall reading something by Diana Walstad that said that the green water being studied, upon examination, consisted of many different varieties of algae mixed together. It could be that any given visible sort of algae in your tank is actually a group of closely related cousins that could morph over to prodominately the sort that can tolerate that change in salinity. 

I know that with green ponds, no one has ever mentioned salting the pond to cure any sort of alage. In fact, as salt will hurt the biofilter (according to my notes from wherever) I had a caution to avoid raising the salt by more than 0.1% in a day to a max of 0.3% or the biofilter would be shocked. Mess up the filteration and the aglae will definately get worse.


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## _~King~_~Tiger~_ (May 11, 2003)

Well, the general idea being mentioned was that the salt would hinder the growth of plants (not kill them) preventing them from taking up nutrients as well as they could otherwise.

...and that the salt would also encourage algae? :?


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## anonapersona (Oct 19, 2002)

http://www.koivet.com/html/articles...ticle_id=131&category=1&search_term=salt test

Ok there it is, I don't know that it helps you much, but many plants seem to tolerate 0.3% in a pond for 2 weeks.


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## anonapersona (Oct 19, 2002)

The bigger question is whether fish need a "tonic". I've read from varoius experts that I have great respect for that it helps a bit, a lot, or none at all.

I've come down to thinking that a salt dip is a great thing for the new fish, and after that, salt is mostly just useful for places where nitrites might be an issue as in cycling and in goldfish tanks (messy and always overstocked since they need 20 or 30 gallons per fish for optimum health), but irrelavant at very low levels.

edit - realizing now that this is posted under algae... I dont add salt to my tanks because I can see how salty the water is that I put in my plants. Or maybe that is just hardwater deposits, I can't really tell, but it looks like a lot of salt. I know my water is moderatly hard with a GH of 10 and adding additional salt to that seems not good to me.


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