I have been dosing my 55 gallon tank with 1 tsp of salt per gallon for about the past five days. I intended to salt to 0.1% to protect my fish from the adverse effects of nitrite as I cycle my tank. I have been using the Top Fin salt from the ***sMart (which is a very fine grained salt). I have been keeping a careful log of salt in and salt out with water changes and am confident that I haven't made any major mistakes in that regard.

Earlier this week my cycle was doing really well -- ammonia had gotten down to zero, nitrites weren't accumulating as fast, and nitrates were starting to show up. But since I added salt things seemed to stall out -- all of a sudden I was back to seeing ammonia and my nitrates weren't rising. Today I tested and I got zero for nitrate, 0.25 for ammonia and 0.25 nitrite (even though it was a peas-only day for my fish).

So I happened to buy a salt level test today at the pond supply store (it is a liquid test with two bottles and works like the KH test where you count how many drops it takes to make the water change color). I tested my tank water and found out that I was salted to 0.28%, not 0.1%!!! I am thinking that this is because I was using a fine-grained salt rather than a coarse-grained salt (so more salt was fitting into a teaspoon). I just did a 50% water change and am still only down to 0.14% salt. I am going to change out more water later this evening to get down to 0.1%.

I am guessing that the high level of salt stalled out my cycle because it was interfering with the development of the nitrobacter bugs that I need to complete my cycle. Is this possible? I know that salt up to 0.3% isn't supposed to interfere with an established cycle but can it prevent a new cycle from maturing?

Anyway, I wanted to point this out because I don't remember seeing this distinction explained anywhere in the articles on salting or cycling (it is certainly possible that I missed something somewhere, however). If I am right in my thinking, if someone using very coarse-grained Kosher salt is going to end up with a much lower salt concentration than someone using very fine salt. This could make a dangerous difference if people are intending to salt to 0.3% and are ending up with nearly 0.6% salt! Particularly if you are salting for medicinal purposes, I would recommend that you get the test to monitor things, rather than relying on measuring spoons and a log.

It probably depends on just how tightly the salt is 'packed' too. We have discussed this once or twice but its probably buried in other threads, so good idea to bring it to the forefront. Really the absolute way to do it is use a kitchen scale to measure out a certain weight. One gallon of water weighs 3.58 kg. Therefore 0.1% salt is 3.57 grams per gallon. So it you have 20 gallons, you want 3.57 * 20 = 71.4 grams of salt per 0.1%.

If you don't have a kitchen scale, take that fact that you know you want 71.4 grams for your 20 gallons, and look at the back of the package. Mine say it weighs 0.7 grams per 1/4 teaspoon. So, 2.8 g/tsp means you need 25.5 tsp (that's 71.4 g/2.8) for 0.1%. Don't worry about being precise, I assure you the packaging is not, but anywhere around 25 tsps should be fine.

But really I'd recommend you do get a kitchen scale because it comes in handy for fish things, food, measuring package weight for pre-printed postage, etc, etc.

I've been researching this topic myself here at kokos, and I just read the pinned article in this forum entitled "using salt"

http://www.kokosgoldfish.invisionzone.com/...60876&st=20

In it you give a slightly different weight for a gallon of water, 3.78 kg. So it works out to 3.78g per gallon to achieve .1% salinity. Depending on how big the tank is, this may or may not make much difference, but they don't call me pedantic for nothing.

Whoops, you're right, that was a typo above. 3.78 kg is correct. I was rushing to finish that post before i went to bed last night and messed up a bit. Unfortunately I can't go back and edit it anymore, oh well.

Thanks so much for the info about salt weights. I do have a very precise digital scale for measuring herbs at my office. I could use that to measure salt. For the time being, I will also confirm my dose with the salt level test.

Any thoughts about whether the excess salt could have stalled out my cycle? I guess I will know more about that in the next day or two as I test water parameters now that I am down to 0.1%.

Is it possible to get something on this topic pinned so that someone else doesn't make the same mistake I did?

Yes - excess salt will stall a cycle.

That is the reason I always type "large grained aquarium salt" every time...... if you are using a spoon measure. It makes all the difference in the world.

Weighing it is always better - but not always possible.