Using Aquarium Salt in Freshwater Tanks

[HN1]

Ok, I have to add one thing to this. As for plants and salt:

My 80g is a brackish water tank. I now keep my salinity at 1.009-1.011. This is a heavily planted tank. My plants are doing better in that tank, without the use of any ferts than in my FW tanks with ferts. So to say plants and salt don't work is incorrect. Not meaning to sound like I know it all or anything HN1, but on this one I hate to say you are wrong. There are plants that can be used in a BW system. Some people use the aquarium salt for BW systems, I prefer reef salt. I doubt that makes much of a difference.

As for adding salt to a FW tank, IMHO, I do agree with HN1, unless you are treating for illness there isn't much point. I do, on occasion, soak my nets in a mixture of aqu.salt and hot water. But that's it.

What am I wrong about exactly?

 

[mfdrookie516]

I think she was referring to your significant other... in regards to the plants Since she does agree with you in the next paragraph

 

[TCool]

So I have this milk carton-looking thing full of API aquarium salt . . . and I don't know what to do with it, or even why I would put salt in a freshwater tank. I originally bought it to try and use it for Ich treatment (I couldn't make that work).

Yet, when I was last at my LFS, I noticed that every tank had a covered plastic cup full of aquarium salt in the back corner of the tank - it was like the cups that bettas come in, with holes drilled in the lid. There must be a purpose for aquarium salt, but I can't seem to figure out what.

Enlighten me? How should I use my carton of salt?

I had read somewhere (can't remember where now) that salt is good to use when you have nitrites. I decided to do a little research on that and it turns out that (according to a couple white papers I read) if you have nitrites it is very important to use salt.

So, here is the justification: Nitrites absorb through the gills and turns hemoglobin in the blood to methemoglobin. Methemoglobin does not allow the blood cells to carry oxygen, so basically the fish suffocates.

Chloride in salt competes with nitrites and basically blocks the uptake through the gills of the nitrites. Therefore, the hemoglobin is protected and the cells can continue to transport oxygen. You apparently need about 9 times more chloride than nitrites to give your fish good protection.

I also read that 1 PPM of salt equals .80655 PPM of chloride, so 1.24 PPM of Salt = 1 PPM of chloride. So, if you have 2 PPM of nitrites you would need 18 PPM of chloride which would equal 22.32 PPM of salt or .002232% (22.32/1000000) salinity (not a whole lot).

So, lets say you have a 55 gallon tank with about 5 gallons or so displaced by stuff in your tank (like me ). That means you have 6,682 ounces of water (if I did my calculations right). In order to reach .002232% salinity you would need to solve a little equation: x / (6,682 + x) = .00002232. So, according to this information you would need to add about .15 ounces of aquarium salt to your tank in order to protect against 2PPM of nitrite in a 55 gallon tank with about 5 gallons of water displaced.

I, unfortunately, do not have a food scale or anything, so I was unable to see how much a tablespoon of aquarium salt weighs. But, on the API box it happens to give you the number of gallons it treats, the total weight of the salt in the box, and a guideline for how much to add. I figured they would calculate the number of gallons it treated based on the smallest amount it tells you to add (looks better to have a bigger number). So, using that information I calculated how many tablespoons total there were in the box, and divided the total ounces by that and came up with about .9 ounces of salt per tablespoon (if anyone has a scale and could measure a tablespoon of API aquarium salt for me that would be awesome!).

So, if you follow the API general recommendation for tropical fish you are adding .9 ounces for every 5 gallons of water. That comes out to .9 ounces of salt for every 668 ounces of water. This equals: .9 / (668 + .9) = .00135 or .135% salinity. This also equates to 1,350 PPM of salt or ~1088 PPM of chloride.

Anyway, my point is that there is a very good reason for using salt if you are having nitrite issues. Another point I'm trying to make is that it takes a very small amount of salt to protect against nitrite, and the API recommendations is far more than needed. So, if you have nitrite issues using the recommended API dose should be more than enough protection. However, based on the information I read using salt is not fool proof and some fish can still have problems and die due to nitrite. So, the use of salt is no replacement for good maintenance of your aquarium as the best protection against nitrites is just not having them. But, if you get in a pinch (like me) and need to use it, it should offer some good protection against nitrites.

I just want to note that my calculations depend on a tablespoon of aquarium salt equaling .9 ounces. That calculation was based on some assumptions that may prove wrong, so, like I mentioned before, it would be awesome if someone could actually measure it for me. One more number it depends on is 1 PPM of salt equaling .80655 PPM of chloride. I can't remember where I got that number from, just had it written down in my calculations, so if anyone knows that is wrong let me know so I can recalculate.

Also, I forgot to save the papers to my favorites, and I'm going off all the stuff I wrote down yesterday. I'll try to dig those up again and post them. I hope this helps someone. I did a decent amount of research over the past couple days because my nitrites are starting to spike (for those of you who haven't read my other posts, I accidentally destroyed my cycle) and I wanted to offer my fish some protection. So, I figured I'd post some of the stuff I learned.

So, to answer your question. You should probably use your salt by keeping it around in case of emergency.

EDIT: Found one: http://www.ca.uky.edu/wkrec/NitritePonds.pdf

 

[lionheart]

1 table spoon of api aquarium salt on my kitchen scales
weighed 7/8ths oz or 25 grams

 

[TCool]

1 table spoon of api aquarium salt on my kitchen scales
weighed 7/8ths oz or 25 grams

So, about .875 ounces. I was pretty close with my estimation.

 

[lionheart]

there is 28 grams in 1oz so its less than a 1oz per tablespoon
so yes you was not far off
on the api aquarium salt actual box /carton which is 16oz net weight 454grams
it states it treats up to ( 107 ) u.s gallons (404 L )

 

[TCool]

Yeah, I used the info from the big box to estimate the weight of one tablespoon of aquarium salt. I used the lowest recommended dose in my calculations because I figured they'd use that to calculate the 434 gallons the big box says it treats.

So, 1/2 teaspoon per gallon. That equals 1 tablespoon for every 6 gallons. 434 / 6 = 72.3 tablespoons in the box. 65 oz in the box, so .899 oz per tablespoon.

 

[HN1]

Very interesting conversation, BUT the fact remains that salt in FW aquariums isn't really needed. It helps while in peak nitrite with fish during cycling or when treating parasites, but beyond that it is only a profit center for the store.

 

[lionheart]

well i bought my aquarium salt to re-activate my nitro zorb pouch i used when i had nitrate issues
ive never used it directly in any aquarium
well i dont think my pleco and catfish would be too pleased

 

[TCool]

Very interesting conversation, BUT the fact remains that salt in FW aquariums isn't really needed. It helps while in peak nitrite with fish during cycling or when treating parasites, but beyond that it is only a profit center for the store.

I agree. Even when using it for a nitrite spike, using it as directed is using way more than you need to use. I used the 1 tablespoon per 5 gallons like it says on the box (before I read up a lot on this) and if I did my calculations correctly it brought my salt up to like 1500 PPM when I really only needed between 50 and 100 PPM.

So, I think it's good to have on hand for fighting off any diseases that may accidentally get introduced into your tank, or for any nitrite issues. But, if you take good care of your tank a small box of the stuff should last you years. Like you said, it's a huge profit center for the store because they convince you that you need it in your tank at all times.

So, back to the point of the topic. My opinion is to always have a small amount on hand in case of emergency. But, don't ever let the people at the fish store tell you that you need to keep certain salt levels in your tank at all times. I'm sure it could have its benefits for a neglected tank (like mine always were) but it's so much cheaper to just keep your tank in good health.

 

[TCool]

well i bought my aquarium salt to re-activate my nitro zorb pouch i used when i had nitrate issues
ive never used it directly in any aquarium
well i dont think my pleco and catfish would be too pleased

I was always one of those suckers who believed the people at Petco and Petsmart knew what they were talking about. So, I've kept my salt levels in my tank consistently at .15% salinity over the past 6 or so years. I don't think it ever had any negative effects on my tank, and my Pleco never seemed to have any issues tolerating it (He's at least 6 years old now and still going strong). That being said, I doubt it had any major positive benefit either. Was just a waste of my money.

 

[ezy33]

I'm old school, when ever my system seemed to be on the Verge of some crash. I would toss a couple of handfuls of plain salt into my 180 gallon along with a water change. This seemed to act like a astringent. The change in salinity seemed to improve the health of the fish. Kind of like a cure all. If the problem persisted then I would go to the LFS for help.