Can our seawater go “bad” without us noticing?

[Luminous74]

Lately, I’ve been wondering if our seawater can go “bad” without us being able to detect it through home tests or ICP analyses. This ties into the ongoing debate about whether water changes are really necessary to reduce the buildup of certain substances—or if they’re not needed at all.

My question is: Are home tests and regular ICP analyses enough to monitor water quality? What about things we can’t measure, like toxins from corals, hormones in the source water, or pesticide residues? I use activated carbon and ozone to bind or neutralize such substances, but is that enough?

What do you think? Have you had similar thoughts or experiences?

 

[shakacuz]

i'm sure we will eventually be able to test water much more accurately or in depth like for toxins, pesticides, etc. our hobby grade kits can only do so much

for now, aquabiomics should suffice in terms of providing some additional information that ICP's or hobby kits don't/can't test for.

 

[Randy Holmes-Farley]

Yes, there are many things we cannot test for, notably organics and what form the inorganic elements take.

 

[rishma]

Lately, I’ve been wondering if our seawater can go “bad” without us being able to detect it through home tests or ICP analyses. This ties into the ongoing debate about whether water changes are really necessary to reduce the buildup of certain substances—or if they’re not needed at all.

My question is: Are home tests and regular ICP analyses enough to monitor water quality? What about things we can’t measure, like toxins from corals, hormones in the source water, or pesticide residues? I use activated carbon and ozone to bind or neutralize such substances, but is that enough?

What do you think? Have you had similar thoughts or experiences?

I have never had any interest in the no water change approach. I know people do it successfully which is great, but I also appreciate there are a lot of unknowns about water chemistry, trace elements, organics and the potential buildup of things we don’t measure for that could ultimately be problematic. While I am fairly technical about my reef keeping, I have been around long enough to see our understanding of water chemistry grow 100-fold. I imagine this will continue over the coming decades. In the mean time, water changes (whether manual or automatic) help me compensate for those things I don’t yet know about.

I do the periodic ICP, but I understand the limits of that data well enough to appreciate how incomplete the picture is.

Water changes have supported my successful reef keeping for decades and it’s quite a simple process. Water changes, testing, and dosing mean I never worry about my water going bad.

 

[brandon429]

For sure it can. Great post. Pico reefers especially since they change all the water, it can't be an anoxic stew when added

Over time and at the expense of great loss there's only one way I'll store change water

Open capped in a room or closet, doesn't have to be heated or circulated just open capped. To use, set container in warm sink, bring up to temp, add distilled, ready for the finest coral

If you want to one day nuke a system you worked hard on for years, introduce the variable of capped storage so "nothing will get in"

 

[Luminous74]

Thanks for all your input!

When it comes to inorganic elements, I’m really not an expert, and it’s been a long time since I was in school. So, I wanted to ask how I should picture this. ICP tests can measure elements like copper, zinc, etc., and the values seem fine in terms of accumulation. But could these elements exist in complexed forms that might actually be toxic?

A similar example is phosphate. ICP tests show that PO4 is present in the tank, but if it’s unclear in what complexed form, we can’t really know if it’s bioavailable to the animals, right?

Personally, I do a 10% water change every week using high-quality salt (ATI Absolute Ocean). I also use activated carbon, run ozone at a minimal dose, and conduct ICP tests a few times a year to monitor for any accumulating substances.

What strategies do you use to maintain water quality over the long term? Do you follow a similar routine or take a different approach?

 

[Luminous74]

For sure it can. Great post. Pico reefers especially since they change all the water, it can't be an anoxic stew when added

Over time and at the expense of great loss there's only one way I'll store change water

Open capped in a room or closet, doesn't have to be heated or circulated just open capped. To use, set container in warm sink, bring up to temp, add distilled, ready for the finest coral

If you want to one day nuke a system you worked hard on for years, introduce the variable of capped storage so "nothing will get in"

You’ve got me thinking. I always prepare my water two weeks in advance and store it in a tightly sealed container, specifically to make sure nothing gets in. So far, I haven’t had any negative experiences with it.

Why shouldn’t I do it this way? What happens to my water during storage?

 

[IceNein]

Yeah, I'm not sure I buy this water in storage thing.

There are situations where closed containers can "suck up all the oxygen." This is a thing in the Navy where there will be compartments of the ship that are sealed, and steel rusting inside will take up enough of the oxygen that it could be anoxic inside. There's a procedure for entering sealed compartments for this reason.

But I would be interested in proof that this occurs and an explanation.

At any rate, I just store pure water and make salt water as I need it. But I could see if I had a larger tank I might store it in a closed brute trash can.

 

[brandon429]

The organic slicks that form over time and foster micro communities that aren't there originally is what gets you

One warm day you cap them, they die and rot

By factoring other types of water storage not from reefing, and thinking the context doesn't matter it sets you up to have surprises

My lfs used an eight foot tall sealed cylinder to sell hq water. If you want to go through maintenance trouble, sediment filters, circulation, occasional cleaning that's fine and don't think they just let it sit there capped awaiting use. It's plumbed to breathe.


Reefers want convenience

And if you want safety, heed the warning of those who lost once but learned the lesson in 2004 and figured out how to stop it

 

[BeanAnimal]

Yeah, I'm not sure I buy this water in storage thing.

There are situations where closed containers can "suck up all the oxygen."

7 or 8 years ago I mixed 40 or so gallons of water for a water change.

I never did the water change.

The water sat in a covered polypropylene tank for at least 6 years, with two old (unplugged) power heads and filter sock that was used as the recirculation filter when mixing. There was a film on the water surface after all of that time.

I used the water about a year ago — turned on the power heads for aeration, tossed 1/4 cup of GAC in the sock and never gave it a second thought.

I don’t see an issue “capping” your stored water for a reasonable duration, fresh or salt. As far as oxygen levels, mixing the water or pouring it into the tank will fix that

Can bacteria grow in stored water, sure. But it is not something that I would lose too much sleep over, personally.


FWIW - that same covered tank is used for my daily SSW top off to replace water lost during automated testing. No circulation pump. Just a 40 gallon lidded container of SSW. It lasts about 8 months at the current rate.

 

[BeanAnimal]

As for water in the aquarium itself, which I believe is the topic here… I would agree with Randy and the OPs assumption that there plenty of things that we can’t easily test for that could certainly affect the systems overall health.

 

[Randy Holmes-Farley]

Thanks for all your input!

When it comes to inorganic elements, I’m really not an expert, and it’s been a long time since I was in school. So, I wanted to ask how I should picture this. ICP tests can measure elements like copper, zinc, etc., and the values seem fine in terms of accumulation. But could these elements exist in complexed forms that might actually be toxic?

A similar example is phosphate. ICP tests show that PO4 is present in the tank, but if it’s unclear in what complexed form, we can’t really know if it’s bioavailable to the animals, right?

Personally, I do a 10% water change every week using high-quality salt (ATI Absolute Ocean). I also use activated carbon, run ozone at a minimal dose, and conduct ICP tests a few times a year to monitor for any accumulating substances.

What strategies do you use to maintain water quality over the long term? Do you follow a similar routine or take a different approach?

It is unquestionably true that many trace elements come in a wide range of chemical forms that impact their bioavailability. Icp testing is only a part of the story. That said, I would not necessarily characterize that as the seawater going bad. It may happen in seconds, and is just a fact of life that we need to recognize and that will vary tank to tank.

 

[BeanAnimal]

There is always DialySeas

Which - honestly I am a bit surprised to still see around after all of these years. I have not seen a mention of it in ages. Interesting concept, just not sure what it actually accomplishes.

 

[Tahoe61]

For sure it can. Great post. Pico reefers especially since they change all the water, it can't be an anoxic stew when added

Over time and at the expense of great loss there's only one way I'll store change water

Open capped in a room or closet, doesn't have to be heated or circulated just open capped. To use, set container in warm sink, bring up to temp, add distilled, ready for the finest coral

If you want to one day nuke a system you worked hard on for years, introduce the variable of capped storage so "nothing will get in"

Too broad of a statement. Using boxed salt water tightly sealed is not a recipe for disaster.

 

[Randy Holmes-Farley]

There is always DialySeas

Which - honestly I am a bit surprised to still see around after all of these years. I have not seen a mention of it in ages. Interesting concept, just not sure what it actually accomplishes.

Not useful, IMO. A water change accomplishes more with less water.

 

[BeanAnimal]

Not useful, IMO. A water change accomplishes more with less water.

Randy said "Why filter it out when you can just dump it out"

 

[Luminous74]

From everything I've read and heard over the past few years, there are certain elements that tend to form bonds more readily, like copper, iron, iodine, and others. Is it possible to categorize all elements by how likely they are to form bonds and how much they resist? And what does this knowledge really contribute when evaluating an ICP test?

When I got back into the hobby about five years ago, after a 10-year break, I was amazed by all the new developments on the market: ICP testing, trace element supplementation systems, and so on. I thought, "Cool, everything has gotten so much easier – now we have everything under control." But the more I dived back into the topic and researched, the more I realized that while many new things had been introduced, they brought even more complex questions that are harder to understand. Sometimes, it feels like we know even less than we did 15 years ago. I know that's an exaggeration, but that's how it feels sometimes.

On top of that, research is made more difficult because a lot of forums and manufacturer websites promote "knowledge" that often lacks real scientific backing but is presented as if it's proven. That's why I really value this forum and its knowledgeable contributors, especially Randy Holmes-Farley. Here, there’s open discussion about what’s actually backed by evidence and what’s just speculation. Thank you all for that!

 

[Randy Holmes-Farley]

From everything I've read and heard over the past few years, there are certain elements that tend to form bonds more readily, like copper, iron, iodine, and others. Is it possible to categorize all elements by how likely they are to form bonds and how much they resist? And what does this knowledge really contribute when evaluating an ICP test?

When I got back into the hobby about five years ago, after a 10-year break, I was amazed by all the new developments on the market: ICP testing, trace element supplementation systems, and so on. I thought, "Cool, everything has gotten so much easier – now we have everything under control." But the more I dived back into the topic and researched, the more I realized that while many new things had been introduced, they brought even more complex questions that are harder to understand. Sometimes, it feels like we know even less than we did 15 years ago. I know that's an exaggeration, but that's how it feels sometimes.

On top of that, research is made more difficult because a lot of forums and manufacturer websites promote "knowledge" that often lacks real scientific backing but is presented as if it's proven. That's why I really value this forum and its knowledgeable contributors, especially Randy Holmes-Farley. Here, there’s open discussion about what’s actually backed by evidence and what’s just speculation. Thank you all for that!

I don’t see the use in such a complicated exercise. There’s no shortcut that allows the exact bioavailability of transition elements such as iron to be known from icp. The major ions such as calcium and bromide do not suffer much from this issue, but many trace elements do.

 

[Luminous74]

I don’t see the use in such a complicated exercise. There’s no shortcut that allows the exact bioavailability of transition elements such as iron to be known from icp. The major ions such as calcium and bromide do not suffer much from this issue, but many trace elements do.

Based on your answer, I’m wondering if my basic understanding is correct. I can check the approximate concentration of macro- and trace elements, but I have no way of knowing whether they are in a bioavailable form or possibly in a harmful, complexed form.

Can I at least detect accumulations? Or is this only partly true, since I can't determine whether harmful accumulation is happening in my animals? At the very least, I should be able to establish a reference against my own measured values.

 

[Randy Holmes-Farley]

Many trace elements are complexed by organics, both in the ocean and in reef tanks. It does not generally make them harmful. It makes them have variable bioavailability depending how strongly they are bound and by what exactly.

There are also different oxidation states, like ferrous and ferric iron or iodide and iodate.