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FAQs on Brackish Water... Water!

Related Articles: Brackish without the salt; Do all 'brackish water fish' really need brackish water? by Neale Monks, Brackish Water System Set-up, Brackish System Components,

Related FAQs: Brackish Water Systems in General,

kH in Brackish Water     6/20/18
"Everything happens for a reason" is one of my favorite sayings (although I find "Everything" to be a bit too broad) and the case of the failure of my filter hose in my Goby tank is an example. Before the hose split, dumped all that water (and my biological filter) onto the floor, and threw the tank into a mini-cycle, I thought everything was fine.
<Indeed! Sounds quite the crisis.>
But I've been struggling to get the tank to re-cycle again.
<So long as the substrate didn't dry out, there should be plenty of bacteria, albeit dormant, in the filter and/or substrate.>
I'm using Prime consistently, so the fish are not being affected, but the ammonia has been "jumping" around from .5 one day, to 2 ppm a few days later; I'll get a slight rise in nitrite, but then it goes away without increasing the nitrate (of which the test shows is less than 10) - it has been very frustrating.
<I would imagine. Nonetheless, I'd still have an optimistic approach here.
The filter bacteria will be there. There's no reason that damp filter media should lose all its bacteria, and indeed it should 'regenerate' into something useful within a few days. Of course do multiple water changes, perhaps 25-50% a day for the first week, and don't add any food. But there's no reason for a whole 6-week cycling process that I can think of.>
But I learned a similar lesson with my 125 gallon tank so I decided to check the kH of the tank and discovered there is none - no kH at all (if that hose had not split and caused the cycling problem, I might not have discovered this until the fish had been affected and might not have put it together even then). I put one drop of the test liquid in the test tube with the tank water and the water remained clear. After putting three drops of the test liquid the water had a slight tinge of yellow (yes, I know it's supposed to turn blue). I had to put in 10 drops of the test liquid before it turned a solid yellow and as I added more, it turned a light orange. I think that what is happening is that the amount of Instant Ocean I'm using to achieve an SG of 1.005 cannot provide sufficient kH because 1) I'm using RO/DI water (human remains in the water), 2) I'm brackish, not full salt, and 3) I'm low end brackish (1.005).
<I would agree with this analysis. Nothing a bit of baking soda can't fix!
Something along the lines of 1 teaspoon baking soda (sodium bicarbonate) per 5 gallons/20 litres should do the trick, but feel free to increase as necessary. Use a KH test kit to keep track, and adjust the dose
accordingly. Experiment with a bucket of water first and see what works. If you want to raise GH, then 1 tablespoon Epsom salt (magnesium sulfate) per 5 gallons/20 litres can be used as well.>
When this same situation occurred in my 125 after I re-homed my loaches, I started using Seachem Alkaline Buffer to bring up the kH (I'm not chasing a pH, just working to establish a healthy kH.
The kH in all the tanks is 8 and that's just fine) and it has been working perfectly in all the tanks. But then I found myself in a quandary - I know Seachem make a Marine buffer, but I'm not keeping a marine tank - just low end brackish, and I was afraid the calculations and proportions in the directions on the Marine Buffer would only apply to full salt tanks.
<Should work, just go 10-50% dosage, as seems appropriate with your KH and/or GH test kits.>
So I decided to use the same Alkaline Buffer I use in my freshwater tanks.
I calculated the amount needed to bring the kH up to 8 like in my other tanks and split the dosage into three parts (I didn't want to do it all at once because I know it will affect the pH - I didn't want to inflict a radical change on the fish). I added the first dosage earlier this morning and when I tested this afternoon the test showed a kH of 3. Unless you think I'm doing something wrong, or you think the Goby and the Mollies need a higher kH, I'll put in the next two doses over the next two days. So that's the purpose of this e-mail - do you seen anything wrong with my thinking or my plan to correct this problem?
<Nope; it's a good plan!>
*Renee *
<Good luck, Neale.>
Re: kH in Brackish Water      6/21/18

Great! Thank you!
<Most welcome. Neale.>

Scat Confusion, sys./salt use     6/29/13
Hello again. I suppose I'm becoming a frequent writer. Today I was told that to be using marine salt to raise the salinity of my scats tank (he's about four inches at the moment) was NOT the way to go- I should be using aquarium salt because marine will raise calcium, and this could damage my fish's organs and shorten his lifespan (!!).
<Utter rubbish. Who told you that…??? Scats live in the SEA. So the one thing you can be sure of is that they LOVE marine aquarium salt mix and the high calcium carbonate levels it brings. Instant Ocean, Reef Crystals, or the generic brand of your choice -- it's all good.>
Well, after having been using marine salt for two months to gradually raise the salinity, we're at 1.004, and now I'm petrified I'm putting my little friend in danger.
He acts just fine- eats like a pig, reacts to me being near him with excitement (ohboyfoodfoodfood)...the only thing I've noticed is that his color is dark, and when he was at my work, they were bright. Am I harming him? How should I reverse this?
<See above.>
I was told to simply cease using marine salt and just use aquarium from now on to get the salinity up...I really hope I haven't harmed him. (I've been cycling the new 65 gallon I plan on putting him in...also with marine salt!! Would I reverse this the same way- or would a water change and then aquarium salt do the trick?)
-long winded Tori
<Rest easy, Tori; you are doing the right thing. Cheers, Neale.>
Re: Scat Confusion    6/29/13

Good. My levels read as such- ammonia is at <1, nitrates/nitrites at 0. pH is ~8.2. Salinity now at 10. I wonder what could be making his colour so dark, then.
<Scats appreciate big tanks, strong water currents, and above all else, reasonably high salinity. Try upping the specific gravity to at least 1.005 and see what happens.>
On the calcium test (i used the Nutrafin test), it was two drops before the water turned people...so his calcium is low. Is there anything you can think of to brighten him up again?
<Carbonate hardness and calcium content of the water will go up with more marine salt being used. Furthermore, mix in some coral sand with any gravel used in the tank. Ideally, add a good handful of crushed coral into the canister filter (a filter media bag may be useful here).>
I don't know what could be stressing him to cause the darker colors. Thank you, though!
<Dark colours on Scats and Monos are usually environmental. Cheers, Neale.>
<<And secondarily from social (bullying) issues. BobF>>
Re: Scat Confusion    6/29/13
Environmental? Do you mean water quality wise, or literal environment (he seriously blends in perfectly with the tank and the decor. Sometimes its a chore to find him even when he's right in my face)?
<Either/any… you need to consider widely… water chemistry, pH stability, salinity, current (turnover/hour), tankmates, etc… Do start here:
Follow the links at top for more… the requirements of this species and its genus are quite well understood.>
Do you have any further suggestions about reviving the bright colors- other factors I may be missing? Thanks again...you guys are life savers.
<Most welcome. Cheers, Neale.>
Re: Scat Confusion    6/29/13
Oh! And should I worry about magnesium and calcium? Where should they be for a small scat of about four inches or so?
<Decent water chemistry (high carbonate hardness + use of quality aquarium salt) should take care of this/these. Cheers, Neale.>
Re: Scat Confusion    6/29/13
My bad! Last PS of the evening- I totally JUST realized that you're the same Neale Monks who wrote the book I've been devouring at work- the Brackish Fishes book. In my efforts to become a brackish specialist I've been reading it cover to cover, and I enjoy it very much!
<I'm very glad to hear this!>

Okay...whew. I think I'm done with post-haste thoughts, now- now I'm just curious about where his calcium and magnesium levels should be, or if I should even worry about those.
<See previous; in short, no, assuming salinity and hardness are adequate, they'll be taken care of.>
That, and other factors that could make him so dark. Sorry again if I seem a bother- this is my first brackish fish, and I adore him. I want him to be happy! :)
<Does he have tankmates? Scats are gregarious, and mix well with their own kind and with Monos and Green Chromides. Avoid two specimens though… three or more Scats works better, or singletons with trios of Monos or Green Chromides. Cheers, Neale.>

Using tap water for Brackish 9/23/12
Hi Crew,
I would like to start a brackish water aquarium using tap water.  The tap water in my area is full of chlorine and ammonia.  With a good conditioner, will I be able to successfully keep monos?
<Chlorine and ammonia combine to form chloramines, which can be neutralized with many Dechlor products. There shouldn't be any free ammonia, but you should test your tap water to be sure.  Once treated, this water should work fine for a brackish tank. As to whether you can successfully keep monos, that depends on your husbandry skills. - Rick>

finding and selecting low range hydrometers, BR and SW f'     2/5/12
Hi WWM Crew,
Your site is pretty much my aquarium bible. Its great! And i have recommended it to a number of workers in my LFS as well as friends. Especially after I overheard some really awful advice being given to a customer at which point I kind of inserted myself into the conversation and offered some advice. Probably should have minded my own business but the clerk obviously had never heard of the nitrogen cycle or prime (which was right there on the shelf) and was selling a bunch of fish to a guy to put in a tank far too small for the number and size of fish he was purchasing. I had to speak up, as politely as I could, but i did manage to educate both of them a bit. I'm no expert, and a year and a half ago i was clueless, but I have studied and read and read and read and now i feel like I'm probably approaching the intermediate level of freshwater fish keeping. I now also have a low to medium salinity brackish tank with only Black Mollies (2 females and 1 baby which has turned out to be a Dalmatian and is now big enough, about 1/4 to a 1/2 inch long, so it wont (shouldn't) be eaten. All 3 are doing very well in this 10 gallon tank. The tank was bought to be a quarantine tank, but I couldn't leave it empty, so after a month of fishless cycling and finally getting the Am and nitrites down to 0 and also, just to be sure, i added a little pure ammonia and watched to see how it was handled, , it disappeared pretty quickly, nitrites briefly bumped up a little and in a day or 2 i was back to Am=0, Nitrites=0 and some nitrates. I then moved 2 mollies from my freshwater tank to this 10 gallon and over time have worked up the salt . I currently use 3 level tablespoons (the measuring spoons, not the food spoons) of Instant Ocean per 10 liters of water with a tiny bit of prime (1/8 cap or so) per 10liters of water change. The tank came with a whisper 10 HOB filter which in my opinion is not adequate for a 10 gallon tank, but rather than replace it with a Whisper 20 I bought a 2nd Whisper 10 to run in parallel, now i can alternate filter swaps and not upset the nitrogen cycle too much. Also, and this is cool, i found 2 cheap sponge filters that fit nicely on the whisper intakes and provide a little more area for nitrifying bacteria to grow in along with keeping any big particles out of the filter. They work great. I just buy empty filter cartridges, I don't use carbon unless I see a particular reason to use it for a week or so. The tank has plenty of plastic plants and a cave, so its not too plain. I also have a large round (4" diameter) air stone which the mollies love to play in, its funny, they actually will swim over the stone and allow it to float them up, then swim out and do it again, after awhile they get bored and go off to do something else. Temperature is 80F, Am is 0, Nitrites are 0 and well, you know how nitrates are, they always climb, but i try to keep them below 20mg/l. I want to measure the SG using a glass hydrometer , the trouble is that the scale i am interested in is 1.000 through say 1.010 or possibly 1.015and that tends to be very low on the hydrometer scale. I just don��t trust any instrument that��s reading close to one end or the other of its full scale. With that in mind I went looking for a suitable hydrometer. They are quite hard to find but I did find these three: http://morebeer.com/view_product/18650/102224/Hydrometer_-_Final_Gravity  http://www.austinhomebrew.com/product_info.php?products_id=2089
They are used primarily in beer and wine brewing . I was leaning towards the first link, the 3rd link seems to have a lot of choices but its nearly impossible to understand what the ranges are, at least for me its extremely confusing. All of those in the 3 links above would need to have their readings temperature corrected. Can you comment on what would be a good choice for my application? Are they even appropriate if i adjust the reading for temperature? If not, what do I do, i suppose i could mix, measure and call it "close enough" but I'd rather know what I really have in there. One more thought, I really noticed a striking change in the mollies when they got into the salted water, they seem much healthier. When they were in the freshwater tank, I had one that had some white stuff on her belly and an especially large glob near the anal fin, I couldn't diagnose it, I watched it for over 2 months, it wasn't Ich, the other molly is coal black and if it was Ich this would have spread. My guess was Columnaris, so i treated the tank for it. It didn't help a bit. But after I moved her to the new tank and brought up the salt (marine salt) level I noticed a distinct change and a definite improvement, so whatever it is, its getting better around the anal fin and as to her belly? Well, maybe she's half Dalmatian. I really don��t know but her baby is definitely a Dalmatian. I'd send a picture but there must be some magic to getting a good shot, I just can't get a decent photo. I need to say one more thing for those reading your site, use a maintenance log program, and log every single thing that you do, measurements, fish deaths, stuff added from chemicals, to salt to plants, lights changed, water changes and how much (I use a bucket with 5 and 10 liter marks on the outside as it seems like almost everything in the fish industry that matters is metric), log it all, it's worth its weight in gold when you can look back and see what is really going on i your tank, not just what you think you remember. I have a log for my 10 gallon and a separate log for my 44 gallon tank. I use Aqua Log, its free and if you set up the columns before adding any data it will be nice and orderly and its simple to use.
<Hello Eric. The short answer is that any hydrometer that runs from 1.000 to 1.030 is going to be useful for fishkeeping. However, a couple of issues. First, it needs to be calibrated (i.e., accurate) at a useful temperature, e.g., 20 or 25 degrees C. If the calibrated temperature is far above or below these, it's less useful. Second, any hydrometer (or refractometer) is only as accurate as its design allows, and consumer grade ones costing a few pounds or dollars will be less reliably accurate that scientific ones costing tens if not hundreds of times more. The best way to be sure is to make up a known concentration (e.g., 35.5 grammes marine aquarium salt in 1 litre of pure/RO water) at the calibrated temperature (e.g., 25 C) and then test the hydrometer. If thoroughly dissolved, which may take 20 minutes or longer, 35.5 g/l should be 1.025 at 25 C. If your hydrometer is far above or below that, then make a note of how far, and adjust accordingly when using the hydrometer. To be honest, brackish water fish largely don't care, so if you're dosing at 5 grammes/litre, an ideal amount for Mollies, you should register SG 1.002-1.003 on your hydrometer, but if its a bit above or below, no worries! Go with salinity (grams/litre) over hydrometer reading any day of the week. Fish experience the salinity; specific gravity is immaterial. Cheers, Neale.>

crab water quality, salt type/s    11/4/11
I recently set up what I thought was a brackish tank for one red clawed crab and a few guppies. I got all animals from a LFS that was going out of business. They said they used aquarium salt and iodine supplement.
After doing some more research I see you site says aquarium salt will not do long term.
<Ideally not. Mixed with Epsom salt and baking soda it would be okay, but the ideal would be to use marine aquarium salt by itself.>
I have a partial package of instant ocean marine mix but do not know what the measurements for adding it to the tank are. It only says to use full package in 5 gallons water.
<For a low-end brackish aquarium, something around 9 grammes/litre should be ample. There's about 6 grammes per teaspoon, so you shouldn't have much difficulty estimating this amount: 1.5 teaspoons per litre!>
What would the correct measurement for adding that? Also, is that what I should order since I have to order salt for correct brackish water?
<You can use your tonic salt until it's used up, but after that, buy the marine stuff.>
It will be a few weeks before anything gets here. I saw on another question you told the person they could "add 1 teaspoon baking soda (sodium bicarbonate) and 1 tablespoon Epsom salt (magnesium sulfate) per 10 liters alongside the aquarium salt.
<Yes, adding those amounts to baking soda and Epsom salt should be helpful.
Ignore the salt amount quoted there, because that recipe is for freshwater, not brackish water, conditions. In other words, per 10 litres, something like 1 teaspoon of baking soda, 1 tablespoon of Epsom salt, and 15 teaspoons of tonic salt should provide a specific gravity around 1.005 while also producing hard, alkaline chemistry.>
These will provide some of the minerals crustaceans need for their shells.
<Correct; do see above.>
Also, add the iodine, either in the water, or through foods rich in iodine". Should I do that until I get the correct stuff in?
<Alongside the others, at 50% the dosage on the marine aquarium iodine bottle.>
How long can I use that for?
Will all of that be safe for the guppies?
<Yes, but it's questionable whether crabs and guppies will get along...>
Do I simply add that when I do water changes and let it dissolve before putting into tank?
<Simply add.>
Also, the iodine supplement I have is very concentrated and I am not sure what the correct dosage is. The directions are one teaspoon (one capful) per 50 gallons each day. My tank is only a 20gallon.
<Sounds like a couple drops should be ample.>
Thank you for your replies.
<Cheers, Neale.>

Brackish water  3/13/10
Hi Peeps,
I just found out about Neale Monks book, "Brackish-Water Fishes: An Aquarist's Guide to Identification, Care & Husbandry". I've heard great things and plan to get a copy soon.
<Well, I'm pleased to hear that!>
Question: I have a 10 gallon (~ 8 gallon water column) brackish water, planted tank. It's been up and running for almost a year, housing some Bumblebee gobies (possibly, Brachygobius nunus), fancy Guppies and a growing population of RCS, (N. denticulata sinensis.) I would like to add water with a SG ~ 1.007 and keep the tank water the same, 1.007.
<Absolutely no need to keep the tank this saline. For BBGs and Guppies, something around 10-15% seawater salinity, 3-5 grammes of marine salt mix per litre, will be ample (one level measuring teaspoon of salt mix is about 6 grammes, so basically half to just under a level teaspoon per litre should be fine). That's a specific gravity of about 1.001-1.002. Since you want plants, I'd recommend a lower salinity, but at the same time, you seem to have a very low pH for brackish water, so I'm worried that you're not adding nearly as much salt as you think you are.>
If I believe my reading of the refractometer, I am doing just that.
<I'm not sure that you are.>
Some other water parameters are; Ph of 6.4,
<Far too low for Guppies, in the long term.>
4dKH, 25dGH, and a water temp around 76F. What worries me (if I haven't already said something worrisome), is the amount of sea salt that I add. 3 tablespoons of Tropic Marine Sea Salt for roughly every 5 gallons.
<One tablespoon is three teaspoons, so you're adding 3 x 6 = 18 grammes per 5 gallons, about 19 litres. That's just over a gramme per litre, far less salinity than you're reading from your refractor. Remember, salinity is easy to measure: it's the mass of salt you're adding to the water. The specific gravity on the other hand is easy to get wrong: it depends on you using and calibrating a refractometer or hydrometer correctly. I'm sure you're not using your refractometer correctly if you're adding 1 gramme per litre, barely over SG 1.000, and yet you're *reading* SG 1.007. Had you said 1.0007 -- note the extra decimal place -- then I'd believe you.>
I change 50-60% of the water every 8 to 14 days. Every one seems happy.
Should I keep with the program? Some of the plants are; Limnophila aromatica, Vallisneria, Echinodorus and Java ferns. They also look fine and dandy, as long as I keep adding CO2. Anything you can say will be appreciated.
<Dump the refractometer, and simply weight out the salt from a dry, airtight container within which you store the salt. Stir into each bucket of water as required. If you're adding 5 grammes per litre, and you're making a 15 litre bucket, then 5 x 15 = 75 grammes per 15 litre bucket.
Easy as pie. Have a look at my Brack Calc application if you're still confused; it runs on Macs and Windows.
Sincerely Yours,
<Hope this helps. Cheers, Neale.>

Re: Brackish water 3/15/10
Thanks for the quick response.
<Happy to help.>
I decided to take another look at what I was doing and to re-calibrate the refractometer (off by about 1.0063 as you thought). I remember using the half a teaspoon per litre rule at first.
<It's not a "rule" but a guideline. Use the teaspoon = 6 grammes guideline to make up the bucket of water, and then use your hydrometer or refractometer to check the specific gravity. Add more salt or water to get the precise specific gravity you want.>
I was acclimating plants and fish before raising the salinity to 1.007.
Just, I never raised the salinity after my refractometer arrived. lol God looks after fools and babies.
<Or else sometimes lets the baby crawl right off the cliff...>
So, to recap, I am replacing 17 litres, I add around 50 grammes of salt and I am trying for a SG of about 1.001.
<Aim for SG 1.002 to 1.003 for best results; SG 1.001 is too low to make much difference.>
You mention raising the pH. What about adding Potassium Carbonate?
<Why? If you use marine salt mix to raise the salinity to SG 1.003, the pH and carbonate hardness will be taken care of all by themselves.>
Lastly, what about adding a small amount of sea salt to a 20 gallon tank, housing Angelfish a few days before a water change?
<What possible reason might there be for this?>
Thank you so much!
<Cheers, Neale.>

Re: Brackish water   3/17/10
I know this email seems a little scrambled but I hope you will make some sense out of it. The SG is now slightly lower then 1.003 and the pH is around 7.2-7.4, but the pH test is for fresh water and my yeast has stopped
pooping out CO2. I know CO2 can lower the pH but have been told not to worry about that.
<Sort of. In brackish water, pH generally stabilises around 7.5 because of the calcium carbonate in the marine salt mix. But if you do choose to use CO2, you will need to test the pH and adjust your CO2 source accordingly.
There's a complex relationship between pH, carbonate hardness (KH) and the amount of CO2 needed for optimal plant growth.>
Once it's running however, I do expect another drop in my pH.
<Below pH 7.4, brackish water fish aren't going to be happy.>
I have 4dKH in the tank. If Tropic Marine Sea Salt will increase the KH I have never seen it IME and nothing says it will raise the carbonate hardness on the box.
<It's a given. Marine salt mix -- as opposed to "tonic" aquarium salt -- replicates natural seawater in containing many minerals other than sodium chloride. Almost certainly the package the package will state this. I have a box of Tropic Marin salt mix right here, and one of the side panels is covered with a list of the 70 trace elements in the box! Anyway, marine aquarists call carbonate hardness "alkalinity", and that may well be described on the box.>
One thing I have been trying is some sort of Calcareous rock (bubbles when I drop it in vinegar) inside the CO2 reactor. I just thought adding Potassium Carbonate would add some K+ for the plants and raise the KH a little. : )
<Wouldn't bother.>
<Most of the plants that do well in brackish water can (or must) perform biogenic decalcification, which means they use carbonate hardness as a source of carbon for photosynthesis. Vallisneria and Elodea are two examples, and the harder the water, the faster they grow. Other plants grow so slowly that it doesn't matter either way. Java fern and Cryptocoryne wendtii are two brackish-tolerant plants that too grow slowly to be bothered by the lack of CO2 fertilisation. In other words, I'd run your tank as a brackish system, skip the CO2, see which plants do well, and throw out any that don't. Much easier! Cheers, Neale.> 

Instant ocean, Synthetic salt mix/es for making brackish water  -- 1/27/10
hi! I was wondering I got instant ocean and will it work for making a brackish tank? also would it be any trouble if you could tell me instructions on how much I put in? thank you see you later!
<Will... read here:
and the linked files above. Bob Fenner>

Use of Marine Buffer in Tropical Brackish Tank for Green Spotted Puffer   7/26/09
Hi Guys,
I am setting up a 46 Bow Front aquarium for a pufferfish (green spotted). I live in an area (St. John's, Newfoundland, Canada) where the water supply comes from fresh water rivers that drain into a peat bog/pond, so is soft (about 6.5-6.9 pH). I intend to use synthetic marine salt mix and measure it with a hydrometer to get it too 1.005 specific gravity. Here is my issue:
even with marine salt mix added to make the water brackish the pH and hardness seem too low to me. When I measure the pH with my test kit (Hagen Master Test Kit, or the Hagen mini masters test kit) I cannot get it to go over 7 to 7.3. I want it to be at 8.
<For juvenile Puffers at SG 1.005, this pH isn't all that bad, and if you add some carbonate hardness to the system, e.g., crushed coral in one of the canister filters, you should find the pH rises a bit anyway.>
If I add some SeaChem Marine Buffer will this work?
<Yes, though a half-dose might be all you need. Personally, I'd simply use
an Rift Cichlid salt mix, as here:
A half or full dose should be ample.>
The label advises that it will raise the pH to 8.3 and buffer it too. The water has low carbonate hardness as well. Also, when I set this aquarium up should I just add the salt, the marine buffer (if okay to use), set temperature and equipment, and then wait? I tried to set up a brackish water aquarium prior but couldn't get the Ammonia to go down to zero after about 2 months and just gave up knowing if I could raise the pH with the ammonia present everything would likely just die.
<Ammonia won't ever reach zero if you do any of the following: [a] Overstock the tank. [b] Provide inadequate filtration, or use inappropriate media for biological filtration. [c] Overfeed the fish dramatically.
Pufferfish need generous tanks, and while your tank should be adequate for an adult specimen, possibly two, this does depend upon well filtered the system is. At minimum, you want a filter rated at 6 times the volume of the tank, in this case 276 gallons per hour (i.e., 4 x 46). Personally, I'd up that a bit, and keep my puffers in systems 8-10 times the volume of the tank in turnover per hour. Filters should be predominantly biological in nature, with good quality sponges and ceramic media. These media should be cleaned every 4-6 weeks by rinsing them in a bucket of aquarium water.
Crushed coral in a media bag could be added to one compartment in a canister filter. There's little/no use for other media: carbon, nitrate remover, Zeolite, etc., and in fact using these "wastes" useful capacity of a filter, potentially allowing ammonia levels to stay high even when turnover levels are adequate. (Though admittedly, after a couple of weeks, carbon becomes a good medium for biological filtration bacteria, though at the same time stops doing any of the things carbon is assumed to perform.>
I am sure that I read that adding the synthetic marine salt mix would take care of the pH and the KH.
<It will at adequate levels; at SG 1.010 at 25 C, you should find pH and KH very stable and at ideal values. You certainly can keep juvenile GSPs at that level, though it's more normal to keep adults, upwards of 8 cm/3 inches, at such levels.>
Is this true, or do I have to do something else as well to "fix" the water so it is right for a green spotted pufferfish. I will do anything I can do or buy anything I can purchase to make the tank correct.
<Cheers, Neale.>

High nitrate levels in tap water - Brackish aquarium, should I use RO water? 7/12/09
Hello, I am Penny.
I have a 21 US Gallon cycled tank containing one 2 inch green spotted puffer Tetraodon nigroviridis (brackish). Temp 26 C, pH 8.0, aragonite sand substrate, TetraTec ex 600 canister filter. SG 1.005. I have artificial plants.
<Sounds good for now; but do understand Tetraodon nigroviridis gets fairly big, 2-3 times the size it is now, and you'll want a tank some 2-3 times bigger than your 21 gallon system.>
The problem is my tap water has nitrate levels of 40mg/l (ppm). I put a JBL Clearmec nitrate/nitrate/phosphate reducing pouch containing clay beads/resins in the canister filter a few days ago but it isn't doing much for the nitrate levels. Am I just being impatient?
<No; these pouches have little/no impact on high nitrate levels; they're really for marine tanks where nitrate levels are lower. Total waste of money in your aquarium. Regular water changes would be far better.>
Puffina seems to be thriving so far but I believe that she would be happier with lower nitrate levels.
<This is true, but it isn't a "killer" provided other factors are good.>
Is it worth me using RO water in future?
<Depends on the cost; a 50/50 mix of tap water and RO water (or rainwater) would certainly provide the 20 mg/l level that is considered ideal for these fish. That said, if cost becomes a factor, it'd be much better to
save your money for a bigger aquarium, bigger filter, and just do more water changes.>
My concern with using RO water is that the amount of marine salt I add to it will not be sufficient to replace all the necessary minerals required.
<Won't make any difference; you'd add the same 9 grammes of marine salt mix per litre of water at 25 degrees C to make the SG 1.005 water required for juvenile Tetraodon nigroviridis.>
I have looked at denitrators but opinions on them seem to be very mixed.
<Waste of money.>
Thank you in advance for your help.
<Cheers, Neale.>

Re: High nitrate levels in tap water - Brackish aquarium, should I use RO water? 7/12/09
Thanks for the speedy reply. I am aware that puffy will need a larger tank. I am currently plotting and campaigning, soon my husband will think it was all his brilliant idea :)
I shall get some RO water and do half RO/half tap water, the local shop sells it at about £2 for 25 litres. Well worth it I think.
<Certainly won't do any harm. But in practise, regular water changes, avoidance of underfeeding, removal of uneaten food, the use of a protein skimmer (at SG 1.010 upwards), and an aquarium of adequate size should all provide good conditions for brackish water puffers without the need for the expense of RO water. It's worth noting the toxicity of nitrate decreases as salinity increases, and much discussion of the affect nitrate has on puffers refers largely to freshwater, not brackish water, species. Cheers, Neale.>

Measuring salinity for mollies  7/29/08 Dear WetWebMedia crew, I'm preparing to set up an aquaria hub in my living room for breeding mollies. I want to try and keep the salinity around 20-25%, but I want to know how I can be sure of this during a water change. <25% seawater corresponds to about SG 1.005, or 7.5 grammes of salt per litre of water. If you download my Brack Calc program (Mac/Win) you can see how these three measurements are related to one another and to temperature. http://homepage.mac.com/nmonks/Programs/brackcalc.html Estimating the salinity this way is not very accurate though, because an opened box of salt absorbs moisture, and that in turn makes each gramme of salt mix actually rather less in terms of salt because some of that weight is water. So in practise you need a hydrometer or refractometer. A basic floating glass hydrometer costs about $5 and is accurate enough for this type of work *if used correctly*.> If I measure the water I am removing, and replace it with the same amount pre-treated with the appropriate amount of salt; the salinity will be roughly the same, right? <Correct. The important thing is to remember to REPLACE water taken out with brackish water, but TOP UP EVAPORATION with freshwater, because the water that evaporates doesn't take salt with it.> Thanks, Nick <Cheers, Neale.>

Re: Measuring salinity for mollies  7/29/08 Thanks for the tip! But one last thing- >>Correct. The important thing is to remember >>to REPLACE water taken out with brackish water, >>but TOP UP EVAPORATION with freshwater, because >>the water that evaporates doesn't take salt with >>it. Right so if I understand right, when I'm doing a water change, I want to replace with prepared brackish water, but if I'm just replacing evaporated water, I should use dechlorinated tap water. <Correct. This is exactly the same for marine fishkeeping, by the way.> Also, what's the safest way to take fish from the home to the LFS for trading purposes? <I use 3 to 5 gallon buckets with lids. But you can also re-use any plastic bags left over from when you bought some fish. Big (multi-litre) food containers can be used too. It doesn't really matter what you use, so long as the fish has enough oxygen and isn't exposed to huge temperature changes.> Cheers, Nick <Cheers, Neale>

Re: Measuring salinity for mollies  7/29/08 I noticed you all get this Q allot, but I noticed some inconsistency. For mollies, if I want to keep them in brackish water, will using API Aquarium salt raise the salinity or should I be using a marine salt mix, like Instant Ocean (the only one that I've seen at various LFS) instead? Cheers, Nick <For brackish water fish generally, you want to use standard marine salt mix (Instant Ocean, Reef Crystals, etc.) rather than tonic salt in the aquarium. Why? Marine salt mix contains not just sodium chloride but also a lot of carbonate/bicarbonate salts that raise the alkalinity and stabilise the pH, two things that Mollies and other brackish water fish really appreciate. Tonic salt (e.g., API Aquarium salt) is almost entirely sodium chloride, and while useful as a therapy (e.g., for treating Whitespot or doing "saltwater dips") it isn't a worthwhile long-term additive to the aquarium. To be fair, if you already have hard to very hard water with a high alkalinity (or carbonate hardness), then livebearers including Mollies won't be all that fussed, and you can probably get away with tonic salt. But I wouldn't recommended it, and I doubt it would be cost effective in the long term either. Marine salt mix, when bought in bulk, is inexpensive. Cheers, Neale.>

Re: Measuring salinity for mollies 7/29/08 Thanks for the advice (yet again), I'm glad to finally get a concise answer on the problem! :D <We aim to please! Cheers, Neale.>

Re: Specific Gravity 1.010   01/08/2008 Well I'll be going to someone else and getting some iodine sometime very soon then. <Very good.> I had indeed read about snails and shrimp being brackish, though I had not read much of anything on the Beadlet anemone. I'll for sure check out more info on that. <Actinia equina is a temperate zone, intertidal anemone the size and colour of a strawberry that seems to have an astonishing ability to adapt successfully to extremes. I've kept in in a tropical system with mantis shrimps, and these anemones bred very rapidly, producing beautiful bright red babies all over the place. Not sure what the minimum SG is; I'd expect something in the range 1.015 to 1.018. So well under normal marine salinities, but still much higher than most people keep their brackish systems. Still, I've seen these anemones sold as "brackish water anemones" by online dealers and auctioneers.> What I had been wondering was if there was anything that would be suitable for life that would hang around the middle to upper regions of the tank. <Lots! But relatively little that's actually traded. Your best bet would be to look at biological supply houses for brackish water gobies, livebearers, and killifish. Many are traded in North America for use as lab animals, in part because they can be kept in freshwater, brackish water, or marine aquaria as required by the experiment. The killifish are especially fun to keep.> A fish that would be suitable to live in high-end brackish in the five gallon, or possibly even the fifteen gallon that I have which I'd be willing to set up for that if it meant being able to fit a fish or two happily in there with the other stuff. <A five-gallon tank is very small, and basically only suitable for gobies. I'd be considering things like Desert Gobies (Chlamydogobius eremius), Bumblebee Gobies (Brachygobius spp.) if carefully adapted, and Rhinohorn Gobies (Redigobius balteatus). These latter are very pretty, quite hardy, and will accept anything between fresh and fully marine conditions. A single species of the Vietnamese Zebra Blenny (Omobranchus zebra) might be another option. A beautiful fish, but exceedingly aggressive, so only combine with things like Nerites. It will eat live shrimps, so don't bother mixing them. Should be fine with small anemones though. I've kept Beadlet anemones and blennies together many times. Of course, your own mileage may vary!> And even, if the things that make live rock alive would survive with their salinity brought down that low? <At least some of the beasties in live rock should be fine to SG 1.018, and perhaps a trifle lower. But do remember that while shallow water crustaceans and molluscs are often able to adapt to variations in salinity, things like echinoderms and cnidarians typically can't. So try a small piece first and see how you go.> Thanks man, Collin <Cheers, Neale.>

Can I use non iodized sea salt for a brackish tank?  11/6/07 <In a word, no. To make a brackish water aquarium you need to use marine salt mix. Only marine salt mix has the combination of salt plus carbonate hardness that creates an environment brackish water fish need. Sea salt is fine in the short term, and is certainly better than nothing, but long term you'll only get good results using proper marine salt mix. Cheers, Neale>

Brackish Water, Hardness, and Salinity - 10/07/2007 Hello Neale, <Aileen,> I have been reading many of your articles that focus on the species suitable for hard water environments and oddballs. Thank-you very much. Clearly you have put a lot of time and effort into these. You have been very prolific and perhaps you should compile, expand your articles and write a comprehensive guide in the form of a book! You cover species often not discussed elsewhere in any detail. Do you already have a book? <Yes. It's called 'Brackish Water Fishes' and published by TFH.> I also get the idea that you are very experimental in your approach to fish keeping, that is trying new things with various species (halfbeak fry raising for instance) I have noted that many of the fish generally considered to thrive in a tank with added salt are listed without the mention of salt. <Indeed. Glassfish, spiny eels, halfbeaks, and bumblebee gobies are all freshwater fish that may tolerate salt but don't need it.> I do not know if this is deliberate or not addressed, as this is not the aim of the article. This is particularly in reference to In praise of hard water How hard, alkaline water can be a blessing in disguise <Yes. Water chemistry stability, which comes with high mineral content, can be very useful.> So, here is the question.....Does the high mineral and naturally occurring salts of hard water negate the need for added salt? <No. Brackish water fish need both high hardness and high salinity. Hardness and salinity are not interchangeable.> Is this a matter for experimentation when trying different species with a your particular water parameters? <It has been played with quite a bit, but the bottom line is brackish water fish need brackish water. When kept otherwise, the range of problems varies, but in most cases the fish are nervous, more prone to diseases like fungus, and tend to have shorter lifespans.> Cheers Aileen <Cheers, Neale>

Salt for Brackish 8/16/07 <Hi, Pufferpunk here> I have two F8 puffers in a ten gallon tank and I'm getting a 30 gal really soon. I have my puffers in fresh water now but I'm gonna set up the new tank as BW. I went to the pet store and couldn't figure out what kind of salt to get. They had something for freshwater and then they had marine salt. I asked the fish guru at the store and he said that marine salt might kill my puffers. <Hmmm... not much of a "guru" then!> Is this true or do I have to use marine salt? If so, how much do I add and how often? I would really appreciate any help you could give me. <You have to use marine salt to make brackish water. You'll need to measure it with a hydrometer. The salt should be premixed overnight with a airstone (or better yet, a small powerhead). Do not raise the specific gravity (measurement of salt density) more than .002/week. Your goal will be 1.005 for their lifetime. Once you reach your goal SG (1.005), you will have to replace it with water of the same density, when you do your weekly water changes on the tank. Be sure to find a hydrometer that starts at 1.000. Instant Ocean & SeaTest make them. ~PP>

Re: Converting water, BR, Figure 8 Puffers...   8/16/07 Thank you so much for your prompt response, I'm impressed. I have another question, when I bought the puffer fish the tank they were in was a freshwater tank. I think I should convert the water to Brackish. I don't know how I can do that without stressing my puffers. Should I just start adding salt little by little and monitoring the specific gravity or something? Thank you very much! K.B.D. <For figure-8 puffers there's no rush to change the salinity, so think more about the filter bacteria rather than the fish. Start by doing water changes that raise the salinity to SG 1.002, and let the thing settle at that level for a few weeks. Check the ammonia/nitrate level(s) are safe. If they are, then raise the salinity to SG 1.004. Figure-8 puffers aren't really fussy about the salinity, any anything between 1.003 to 1.010 is tolerable, though 1.004-1.006 is probably the ideal. What matters more is that pH and hardness are nice and high, and that the nitrate levels are very low. So choose a salinity level that isn't a financial burden. There's no point choosing a high salinity if that only means you "economise" on water changes. Your puffers would sooner have clean water at SG 1.003 than dirty water at SG 1.008. Incidentally, there's no harm to varying the salinity every couple of months; in fact, it's probably quite a good idea. No brackish water fish naturally experiences a constant salinity, and the species that breed in captivity (not puffers, sadly) mostly seem to do so when there are salinity changes. Plants generally don't like brackish water conditions, though a few do, so if you're using live plants, research this issue first. Java ferns and Java moss are two of the most reliable species in this regard. Finally, do not use "tonic salt" or "aquarium salt" -- what you want is marine salt mix of the kind used in reef tanks. If you happen to have a marine aquarium, "old" water from a reef tank can be diluted with freshwater and used in a brackish water tank perfectly safely, provided the nitrate levels are nice and low. Cheers, Neale>

Green Spotted Puffers, how to set up water? -- 07/18/07 Hello, <Hi Nicole , Pufferpunk here> About a week ago I bought four green spotted puffers from Wal-Mart. Unaware that they are brackish fish I put them in a FW tank, which is what they had been living in at Wal-Mart. <With 4 of those puffers, you're going to need quite a large tank. Did you cycle the tank?> I purchased the salt to put in their water but I am not sure how much to put in and how to go about doing so. Do I just start putting the salt in or do I gradually add it to the water? <You need marine salt & a hydrometer to measure the salinity. Find one that starts at 1.000. You can raise the specific gravity as much as .002/week or less. For a rough estimate, it will take about a cup of salt/5gallons of water to raise the SG by .005. You'll have to do some math here.> Also, while my puffers are eating well and appear to be healthy, they are developing a case of ick. <Are you sure it's ich? Are there spots on their fins or just their body. Many folks think their tiny spines look like ich.> I know that they are scaleless and the normal medication I would use to treat ick says do not use on scaleless species, so would it be okay for me to use Metranidazole? <See: http://www.thepufferforum.com/forum/library/hospital/fwich/ > The tank that they are kept in is 10 gallons and they range from about 1 inch or less. <I would only put 1 of those puffers into a 10g tank, so you'll need a 40g tank for them now. Eventually, when they grow over 2" & into quite large-bodied 6" fish, they will require 30g each. You might want to rethink this...> I put some Melafix in the water and I am hoping that this will help, but I don't think that Melafix is a cure for ick. <No, it's not but it will sooth their skin, where the parasites are attacking them.> If you could give me some advise on what to do with them, it would be greatly appreciated. <Start by reading: http://www.wetwebmedia.com/BrackishSubWebIndex/gspsart.htm More info can be found at www.thepufferforum.com . Please, please, please do your research before your purchase! These are wild-caught fish & their species is being depleted in the wild. ~PP> Thanks, Nicole

Storing Water for BW use   -- 5/13/07 Hi there, <Greetings.> I was hoping you would be able to help me! I love the site and find it incredibly useful, although have never asked any questions as I was not sure whether I would receive an answer, but have decided to take the plunge (no pun intended). <Very good.> I have a brackish system with 2 baby green spotted puffers, in a 10 gallon tank.  I know its small and I hope to upgrade within 6 months (student), but they both seem incredibly happy! <Yes, a bit small. Possibly viable while very young, but once at 4-5 cm in length, totally inappropriate. Ultimately, these fish will need around 50 gallons for the two of them, because some specimens are somewhat aggressive towards one another. Not always, but often enough for you to take the some sort of precautions.> I was just wondering you talk about storing water for changes.  I was curious, what sought of container do you store it in (stupid question) and how long can it be stored for? <Ideally, a plastic container with a lid (partly to stop evaporation, but also to stop dust and gunk falling in). I use 5 gallon buckets with lids purchased from a paint supply store. Cost very little, a few UK pounds each. Some aquarists maintain you want *food grade* plastics to avoid possible contamination of the water with the solvents used to form the plastic.> Also please tell me i don't need a protein? <Protein skimmers are very useful in brackish water aquaria. They aren't essential in the same way they are in marine reef tanks, but certainly jolly helpful.> Ooooo also...where exactly is this good bacteria that break down the bad stuff living, in the tank? the filter tubes? the filter itself? the pump? <Mostly in the filter medium, which is the sponge, ceramic hoops or whatever that goes inside the filter. Sounds like you would benefit from having a read through this: http://www.wetwebmedia.com/FWSubWebIndex/fwfiltration.htm . When you're done there, skip over to the Brackish section, here: http://www.wetwebmedia.com/BrackishSubWebIndex/BrackishSubWebIndex.htm > Fanx for any info you can give, love ya site! <Please understand that pufferfish are relatively intolerant of poor water conditions, and can only be maintained in *mature* aquaria. The lifespan of two green spotted puffers in an immature 10 gallon tank can probably be measured in weeks, even days.> Over and out! Jack <Good luck, Neale>

Specific Gravity and Mono question  3/29/07 Hello everyone, <Hi Andy, Pufferpunk here> First of all, thank you for the help you have previously provided to me (and everyone else requiring assistance) on this site.  You guys are a tremendous asset!!   <Thank you & you're welcome!> Ok, I tried to find the answer to this on your site but couldn't seem to find it.  I have a couple of questions.   First, the background: 55gal BW tank, 2 emperor 400 filters.   Occupants:  2 Columbian sharks (about 4 inches long each), 2 GSP's (about 2 inches long) and 1 Monodactylus argenteus (sp), that is 6 inches long and tall.  I have been told that the SG should be around 1.014 but have noticed people on your site saying that BW is around 1.010.  What is the best SG for these fish? <BW is actually any SG between FW & SW.  High-end BW, 1.014 is fine.  Eventually those fish will be best kept in SW.  Then you can add live rock & a skimmer, for better filtration.> My other question is do I need to have more than one Mono?  I know they are a schooling fish but will this guy be alright by himself? <Yes, schooling fish are definitely happier & live longer (less stress=stronger immune system=longevity).  A school of 5-6 foot-long fish though, will require a 300+g tank, just for them.> And yes, I am aware that I will need to upgrade to a larger tank in the future as all of these fish get quite large! <Glad to hear you are aware of the adult sizes of these fish.  ~PP> Thanks Everyone!   Andy  

Brackish Means Using Marine Salt  1/12/06 Pufferpunk, Thanks for the response. I am constantly learning in this hobby. I am not sure about the specific gravity. I added 15 teaspoons of aquarium (not marine) salt to the system before adding any fish. <It takes roughly a cup of MARINE salt/5g to make a brackish specific gravity of around 1.005 (suitable for F8 puffers & bumblebee gobies).  Aquarium salt in no way, may your water brackish.  Read: http://www.thepufferforum.com/articles/water/salt.html> My goal was to create a salt content between fresh and brackish. I planned on adding a tablespoon of aquarium salt every third (25%) water change to maintain current conditions. <That's not enough  salt & the totally wrong salt.> I also realize that Siamese Algae Eaters are not made for brackish water. However, I was told by the manager of Aquarium Adventures, Columbus Ohio, that if I wanted an algae eater that would do an awesome job with algae and was from the river systems I was attempting to reproduce that the SAE was my fish. <There are no algae eaters that are comfortable in BW.  Rivers are not BW.  The estuaries between FW rivers & the ocean are BW.  The ocean is made from marine salt, not just plain NaCl.> He explained that the SAE would not do well in brackish conditions but would be fine in a slightly saltier than normal fresh water. <But that's not salty enough for the fish you have.> I also understand that BBG and F8 puffers will be fine in slightly saltier than normal freshwater. <By slightly saltier, yes they are kept in low-end BW (1.005-1.008), as compared to mid range (1.009-1.014) or high-end BW (1.015-1.019).> Therefore, I assumed I could create a SG that would work decently for both. <Can't be done.  You can't mix BW & FW fish in the same tank.> Doesn't the aquarium salt help prevent diseases anyway? <That's bunk--read the article I linked you to above, on salt.> As far as the overstocking, I am guilty as charged. I will be sure not to add anything else to the tank.  Why do people suggest BBG's as tankmates for F8 puffers if they will get eaten? I have never understood why people say (in the same articles) that BBG are great tankmates but also warn they could get eaten by puffers. <Sometimes they do & sometimes they don't get eaten.  Depends on the puffer & good hiding places for all the gobies.> I had quite a hard time finding my BBGs (contacted 30+ pet stores). Only one place had them and out of sure excitement I headed there right away (over an hour drive) and bought all they had. The gobies were pretty small and I feared that the F8 puffer would eat many of them and so though I planned to buy 6 or 7 I bought them all. So far they have gotten bigger (about 1 inch) and seem to be doing fine. I usually count like 14 or 15 and assume 2 could be hiding. They move so fast anyway. I attached a picture of my tank that is supposed to represent where Southeast Asian rivers meet a mangrove habitat. The roots, rocks and live java fern seem to give the gobies hiding places. The puffer has his own huge cave and seems to enjoy it. There are also little cracks and crevices around the cave where the gobies hide. The SAEs seem content to swim around and eat algae and leftovers. <I would suggest a thicket of plants for more hiding.  ~PP> Thanks again. Matt Pace        

Making Brackish Water   1/26/06 Good Evening!! <<Good Evening to you too.>> Is it alright to use the same salt used in saltwater tanks, for brackish water tanks?   <<Not only is it alright, but it's the only way to make brackish water.  Lisa.>>

Specific gravity for a Brackish Tank 4/06/05 <Pufferpunk again> That is an approx for a 20 Gallon tank - correct?? lol just making sure <I use a rough estimate of a cup of marine salt/5gallons, to raise the SG .005. You'll have to do some math & be sure to check with a hydrometer a couple of hours after mixing into tank. Premix into a bucket 1st, to dissolve. ~PP> 

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