Nice local seawater -BUT......!!

[JT101]

Hello all,

Fortunately for me (I think!) I live 7 minutes away from a pristine, gin-clear salwater marsh that I've been keeping my eye on ever since I started this hobby back in June. The water seems full of small killiefish, spearing (silversides), small starfish, hermit crabs, spider crabs etc. I've been strongly considering usin this water water changes. I could be there and back with a couple of 2.2 gallon jugs in under 20 minutes.

Yesterday I finally decided to take a sample of this seawater home and check it out.

What I found didn't surprise me:

Nitrates: 0ppm (as expected)
Nitrites: 0ppm (as expected)
pH: 8.2 (close to what I expected)
Salinity: 1.023 (lower than I expected but still OK)

I took a drop of the water and put it under a microscope and it's ALIVE with plankton and other little "critters" even though it looks clear to the naked eye. So, this water would be pretty nice for my filter feeders. PLUS, it has to be full of good trace elements. Yes, I am a little concerned about runoff and local pollution but there are almost no boats in this area and most of the surroundings are sanctuary land with no development.

Now, here is the part that I DON'T understand:

Ammonia: 0.25ppm!!!

How can that be?

I have the Red Sea Marine Lab and I routinely check my ammonia in my tank. If the test water is yellow, then it's 0ppm. If it's a very light green it's 0.25ppm, a darker green it's 0.5ppm and so on. When my tank was brand-new (before it was cycled) it was reading as high as 0.5ppm but now it's been 0ppm for weeks.

So, how can seawater from a clean, clear bay have ammonia in it but no nitrites or nitrates?? It kills me that I may not be able to use this water.


Thanks
John

[ScubaDrew]

Depending on how 'marshy' it is, it seems there would/could be a lot of dead and decaying plants and animals...

[Xtreme1024]

Using an R/O unit and a good quality salt I think is your best source, too many unknowns with using water from a marsh

[BigAl07]

As ScubaDrew pointed out that's perfectly understandable. It's natural for things to be decaying in a marsh (especially where there is a low flow area) because ammonia is a natural part of the Nitrogen Cycle.

I would strongly be hesitant about getting natural sea water because you have no way of knowing or testing for any local pollutants or contaminants. Even though the marsh itself may be thriving you have to remember it's a larger body of water than your tank and your system is closed in that it's not constantly being drained and refreshed like Mother Nature does her fish tank (Earth). Any contaminants you introduce will not only be trapped in your small eco-system they have the high probability to buiild and build. Even if there are at small levels IN the Marsh over a short period of time they could accumulate in your tank and wreck havoc on your system. It's just not worth the risk in My eyes. Our systems are so fragile compared to what Mother Nature has created and you're just flirting with disaster and tempting fate. I'd mix my own NSW from RO/Di this way you know what's going in your tank and minimizing the unknowns.

Good luck either way.

Allen

[JT101]

Originally Posted by ScubaDrew

Depending on how 'marshy' it is, it seems there would/could be a lot of dead and decaying plants and animals...

Interesting, thanks. I'm still trying to understand the whole chemical relationship between ammonia, nitrite and nitrate. My knowledge so far is that ammonia breaks down into nitrite (which is a highly toxic compound), but fortunately it then gets processed by organisms that convert it to nitrate (which is less toxic to fish but still toxic to inverts).

If I am correct in the above statement then I do not understand how in a marine environment there could be ammonia but no nitrite or nitrate. Isn't any body of seawater (be it a bay, marsh, harbor, sound or ocean) full of the very "stuff" that we as marine hobbyists crave to have in our aquariums but cannot? How can there be so many living, thriving inverts in this area that I took the sample from and yet there is still ammonia?

[BigAl07]

Originally Posted by JT101

Interesting, thanks. I'm still trying to understand the whole chemical relationship between ammonia, nitrite and nitrate. My knowledge so far is that ammonia breaks down into nitrite (which is a highly toxic compound), but fortunately it then gets processed by organisms that convert it to nitrate (which is less toxic to fish but still toxic to inverts).

If I am correct in the above statement then I do not understand how in a marine environment there could be ammonia but no nitrite or nitrate. Isn't any body of seawater (be it a bay, marsh, harbor, sound or ocean) full of the very "stuff" that we as marine hobbyists crave to have in our aquariums but cannot? How can there be so many living, thriving inverts in this area that I took the sample from and yet there is still ammonia?

It depends on the level of decomposition. If something recently died in the marsh then it's just now to the ammonia stage. Nitrates are removed through water changes (water flowing through a Marsh counts as a water change). Nitrites are taken up by aquatic plant life so even in our tanks we can have high levels of Nitrites but due to constant export from the plants into a usable product for nutrition.

Hope this helps some.

Allen

[ScubaDrew]

Just seems like a marsh is going to have a huge ammount of decaying plant matter that is producing a lot of ammonia. I think you've got the chemical process right, but I think it would take a biologist to explain why nitrite and nitrates are being processed/used. i do know that living plants will consume nitrate, so perhaps ammonia is just being produced faster than it can be converted to nitrite, but as soon as its nitrite the conversion to nitrate and then consumption by living plants is fast enough.

either that, or, "thats just the way it is" - both acceptable answers.

[JT101]

Originally Posted by ScubaDrew

Just seems like a marsh is going to have a huge ammount of decaying plant matter that is producing a lot of ammonia. I think you've got the chemical process right, but I think it would take a biologist to explain why nitrite and nitrates are being processed/used. i do know that living plants will consume nitrate, so perhaps ammonia is just being produced faster than it can be converted to nitrite, but as soon as its nitrite the conversion to nitrate and then consumption by living plants is fast enough.

either that, or, "thats just the way it is" - both acceptable answers.

I think you hit it on the head with your comment about the plants (I never thought about that )...

This marsh is surrounded by Spartina so the huge amounts of this grass are probably utilizing these chemicals quickly enough where the nitrites and nitrates are immeasurably small.

[AQTCJAK]

Sea water that is used in tanks is not taken form the shoreline for this very reason. The closer to shore you get the more unatural things pollute the water. You never know what it could be in that water upto & including dead animals & or plants etc... Sea Water is harvested & then clean & chlorinated to kill all or the bad bacteria that exist then it is de-chlorinated so we can use it.

I would not even attempt to utilize the water you have been eyeing if for no other reason you could be introducing a pathogyn that could kill everything in you tank right way

[JT101]

Wow, I guess I didn't think this through...

Oh well, I will refrain from using the local seawater and stick with known sources.

Thank you all very much for the extremely informative posts!

Sincerely,
John

[BigAl07]

One other "addition" is that your local sea water probably isn't the same composition as the "Critters" you're trying to keep. You run a VERY high risk of introducing pathogens (as Jack mentioned) and just random disease and sickness that the tropical inhabitants aren't adapted to fight off. That's like me going to Belize and drinking the water there. It's not a good idea. Just because the locals drink it daily doesn't mean it wont make Allen very Very VERY sickly! Trust Allen on that one.... *runs to bathroom just thinking about it*

[Dentoid]

If there was ammonia in the test sample and no nitrite or nitrate then I would expect this to be from run off or some type of pollution. Did you try taking multiple samples from different locations? Did you try different test kit brands?

[JT101]

Originally Posted by Dentoid

If there was ammonia in the test sample and no nitrite or nitrate then I would expect this to be from run off or some type of pollution. Did you try taking multiple samples from different locations? Did you try different test kit brands?

No, just the one spot, and I used my Red Sea Marine Lab only.

[Dentoid]

Well at any rate, it's not a good idea to use it for the above stated reasons. Chances are you are getting a false positive reading. Perhaps a person upstream peed in the water!

[Melanie]

ha ha ha Dentoid

Chuck uses natural sea water to do his changes, and if I understand correctly, he collects it fairly close to shore. Chuck's Addiction

I did not have a good experience collecting my water myself even 7 miles off-shore.

Perhaps one day I will have an experimental nano that I stock with all things I collect from the gulf. But since my DT is itself an experiment, I better stick to one at a time!