Using Bleach (NaClO) in a reef tank

[Paul B]

I have been using NSW right from the ocean in my reef for 48 years and counting. I used to only use a little of it because I didn't live close enough to the sea but now that it is 90 yards from my house I use only NSW.
I usually filter out floating stuff like chopped up seaweed, jellyfish. sand etc. But it is fine just the way it is.

I also used bleach, "Clorox" to be exact in my reef a few times many years ago. In those days I would put in one cup of Regular Clorox to 50 gallons of water to kill any parasites, worms, sea gulls etc. That I didn't want. (After I removed the fish) That was in the 70s when I would occasionally lose fish to parasites because I didn't know better, now parasites are not a concern so I have no need to do that.

But the first squid eggs were hatched in captivity in bleach treated water. That bleached water is still in my tank as it has never been fully emptied.

I didn't invent the bleach thing, it was "Robert Straughn" The Father of Salt Water Fish Keeping.
I don't use bleach now for anything except to whiten my unmentionables.

 

[brandon429]

Nice recap of using unusual approaches from so long ago that's neat. I had only heard of in tank bleach use in 2015 or so

 

[Reefkeeper12]

For those who thing I have a simple tank, here is a few Pic of my DT, those pictures where taken a few weeks ago, dosing where on:











More pictures? check my signature, page 4
(One year old tank)

That is a sexy tank.

 

[Reefkeeper12]

That is a sexy tank.

I have wanted a powder blue tang for so long but they’re always unhealthy in my experience.

 

[Freenow54]

I also do triton test regularly, i started 2 months ago, last test was 1 week ago and everything was fine.

I start on a test tank, with fishes and softies and all good, now been 2 months dosing my dt 1ml of clorox (5%) twice a week for 500 liters of water, so in my dt I dose 2ml. All good so far.

My orp goes 20 to 30 point up for every 1 ml of bleach, and stay up like 30 minutes and then goes down again to normal . (some days took more to get back)
Less algae in the glass for sure.

My dt is sps mainly. My goal is reduce ich, ich is present in my tank but is soft ich strain, 1 year and no ich casualties. But I have watch good things with bleach, but not 100% sure is because of it.

Please explain ORP to me

 

[Freenow54]

I noticed a beneficial clearing of my water recently. I cleaned my skimmer by running heavy bleached water through it for a couple of hours, and rinsed it using tap water for the same period of time. When I put it back on the tank after about an hour I noticed a huge difference from any residual bleach left. The water became very clear, and algae on my glass, and power head as well as heater. I am tempted to add it during water changes. It is a 45 gallon tank. Thoughts?

 

[bruno3047]

Wow. This is a really old thread.

 

[bruno3047]

Please explain ORP to me

Oxidation-reduction potential (ORP) measures the ability of a lake or river to cleanse itself or break down waste products, such as contaminants and dead plants and animals. When the ORP value is high, there is lots of oxygen present in the water.

 

[Randy Holmes-Farley]

Please explain ORP to me

ORP and the Reef Aquarium - Reefkeeping.com

Simplified ORP

Imagine a reef aquarium as a vast battlefield. No, more vast. Much, much more. OK, that's ORP. That is, ORP is a measure of who is winning and who is losing the battle. The battle is never won by one side or the other. As an aquarist, you do not want it to be, or else everything in the tank would be dead. In other situations, such as the purification of tap water for drinking, allowing the oxidizers to win is fine. A high enough ORP (650+ mv) can kill most bacteria in a few seconds.

On one side of this aquarium battle there are the oxidizers. They all want to get electrons, and they rip them off of the bodies of the enemy. The foot soldiers of the oxidizers are oxygen molecules (O2). Did I say the battle is vast? On one day last week, there were 342,418,226,849,748,675,496,726 of these little guys roaming my aquarium, looking for action. Some of these are paratroopers, arriving at the aquarium out of the air. Others are made in secret labs, otherwise known as photosynthetic organisms such as many corals and algae.

Unfortunately, despite their vast numbers, the oxygen molecules are not very effective fighters. In many cases, they can swarm all over the enemy and still not prevail. The true leaders of the oxidizers are far less numerous, but considerably more potent fighters. These include ozone (O3), hydrogen peroxide (H2O2), triplet oxygen (3O2), and a variety of oxygen radicals, some with such inspiring names such as superoxide radical (O2-). They also include chlorine (Cl2) and chloramine (NH2Cl). It turns out that oxygen molecules (O2) can occasionally morph into some of these better fighters (such as hydrogen peroxide), sometimes all on their own, but most frequently when they get blasted with UV light.

The oxidizers also have other types of fighters. Some are present at very low concentration, but are so sensitive to the state of the battle, that one can gauge the battle by how many of them are left standing at any given point in time. Metals, for example, such as iron (as ferric ion, Fe+++) can serve this purpose. The other oxidizers also include anions such as hypochlorite (ClO-), iodate (IO3-) and nitrate (NO3-), among a host of others.

On the other side are the reducers. The reducers all want to get rid of electrons, and they virtually throw them at the oxidizers. Many of these are organic molecules. They are not as numerous as the oxidizers, but many are much larger. Some are more than 10,000 times as large as an oxygen molecule. So they can make up for low numbers with pure brawn. That is not to say that the reducers do not have small but potent soldiers. The antioxidant vitamins, like vitamin C, for example, are small but extremely potent reducing agents. The reducers also number on their side some inorganic compounds, such as ammonia, iodide, and a really nasty fellow, sulfide.

The reducers come from fish food, metabolic waste products, the breakdown of dead organisms, and certain additives put into the aquarium (e.g., iron supplements that contain ferrous ion). The surfaces of most organisms themselves enter the fray as reducers, waiting to be oxidized by the enemy.

Interestingly, most soldiers on both sides are suicide attackers. Oxygen, ozone, and hydrogen peroxide are all destroyed when they react with a reducer. While not strictly suicidal, most organics are heavily damaged by oxidizer attacks, and are slowly degraded, eventually ending up as carbon dioxide if oxidized enough. They tend to be found in areas that the oxidizers hate; that is, in areas of low oxygen. Yet, the reducers are also sneaky, and even manage to get their hands inside cells (even finding positions in photosynthesis itself).

So where does ORP fit into all this?

ORP is a measure of the relative fighting ability of the oxidizers and the reducers. Think of the surface of the ORP electrode as a surface that these various fighters are hurling themselves against for practice. If there are lots of potent oxidizers around, and not so many reducers, ORP rises because the electrode senses more oxidizing "power" in solution. Likewise, ORP drops if it senses more reducing power in solution.

The exact value reported by an ORP electrode is, consequently, a constantly varying number that represents the ebb and flow of the battle. If you add oxidizers to the aquarium (ozone, permanganate, hydrogen peroxide, etc.) then the ORP rises. Alternatively, if you add a lot of organic molecules to the solution, or restrict the oxygen supply, the ORP drops.

What about pH? pH can impact the ORP readings in aquaria. Often, ORP goes down as pH rises. A typical aquarium ORP reading will change on the order of 59 mv/pH unit. The easiest way to understand this is to simply think of pH as a measure of hydrogen ions (H+) in solution, and to think of H+ as being on the side of the oxidizers. In reality, H+ doesn't usually oxidize things itself (though it can), but more typically it can hype up other oxidizers, like oxygen, making them much more potent. So during the course of a 24-hour day in a reef aquarium, ORP will vary as pH and O2 also vary.

Is ORP a useful measure? That is, should aquarists really care how this incredible battle is going? To some extent, yes. If the oxidizers carry the day, the ORP would rise to the point where the organic molecules that represent the bodies of organisms would be burned away. If the reducers won outright, the ORP would drop below 0 mv. In that case, there would be little oxygen left, and toxic hydrogen sulfide would rule the aquarium. In either case, the aquarium would be a disaster.

So aquarists have to hope for, and to some extent maintain, this battle in a sort of middle ground. That middle ground is typically described as being between 200 and 500 mv. Most aquarium authors have recommended a range of 300-450 mV. Why? Mostly because the ocean often has ORP in this range, and because these authors have successfully operated aquaria in this range.

HOWEVER, there is a significant potential to misunderstand cause and effect with ORP. If a crappy looking tank that is overrun by algae has a low ORP, is the low ORP the cause of the algae, or is the algae the cause of the low ORP? Or are both simply the byproduct of some other process? Does artificially raising ORP by adding an oxidizer like ozone actually improve anything? The answers are not obvious. These and other related questions will be addressed in greater detail in subsequent sections of this article that go into the scientific details surrounding ORP in aquaria.

Most reef aquarists, aside from those that use ozone and must therefore monitor ORP to prevent overdosing, use ORP to monitor if anything unusual happens in the aquarium. A sudden drop in ORP, for example, suggests that the reducers are suddenly gaining ground. That might be because a gush of organic molecules has been released from a dead organism, or because the oxygen supply is not keeping up with demand for some reason. Aquarists might use such information like an alarm suggesting the tank needs to be looked at closely. Most aquarists do not target any specific ORP value as being optimal, in part because ORP measurement is subject to considerable potential error.

So is ORP measurement and control recommended for nonscientists who also happen to be reef aquarists? My suggestion is no. There are interesting things to learn by measuring ORP, and I recommend that everyone with any interest read the following sections to better understand it and decide for themselves if it is worth doing or not. Nevertheless, I have not measured ORP in my aquarium for years, despite having the tools at hand. It is simply not very high on the list of things that one can usefully do to maintain a high quality reef aquarium, in my opinion.

 

[Freenow54]

Wow. This is a really old thread.

Yes I know. It all started with me asking about whether to add bleach as a regular thing. I am very hesitant. But as I said here earlier I experienced something good with very residual probably trace amounts after cleaning my skimmer. Thanks for replying

 

[Freenow54]

ORP and the Reef Aquarium - Reefkeeping.com

Simplified ORP

Imagine a reef aquarium as a vast battlefield. No, more vast. Much, much more. OK, that's ORP. That is, ORP is a measure of who is winning and who is losing the battle. The battle is never won by one side or the other. As an aquarist, you do not want it to be, or else everything in the tank would be dead. In other situations, such as the purification of tap water for drinking, allowing the oxidizers to win is fine. A high enough ORP (650+ mv) can kill most bacteria in a few seconds.

On one side of this aquarium battle there are the oxidizers. They all want to get electrons, and they rip them off of the bodies of the enemy. The foot soldiers of the oxidizers are oxygen molecules (O2). Did I say the battle is vast? On one day last week, there were 342,418,226,849,748,675,496,726 of these little guys roaming my aquarium, looking for action. Some of these are paratroopers, arriving at the aquarium out of the air. Others are made in secret labs, otherwise known as photosynthetic organisms such as many corals and algae.

Unfortunately, despite their vast numbers, the oxygen molecules are not very effective fighters. In many cases, they can swarm all over the enemy and still not prevail. The true leaders of the oxidizers are far less numerous, but considerably more potent fighters. These include ozone (O3), hydrogen peroxide (H2O2), triplet oxygen (3O2), and a variety of oxygen radicals, some with such inspiring names such as superoxide radical (O2-). They also include chlorine (Cl2) and chloramine (NH2Cl). It turns out that oxygen molecules (O2) can occasionally morph into some of these better fighters (such as hydrogen peroxide), sometimes all on their own, but most frequently when they get blasted with UV light.

The oxidizers also have other types of fighters. Some are present at very low concentration, but are so sensitive to the state of the battle, that one can gauge the battle by how many of them are left standing at any given point in time. Metals, for example, such as iron (as ferric ion, Fe+++) can serve this purpose. The other oxidizers also include anions such as hypochlorite (ClO-), iodate (IO3-) and nitrate (NO3-), among a host of others.

On the other side are the reducers. The reducers all want to get rid of electrons, and they virtually throw them at the oxidizers. Many of these are organic molecules. They are not as numerous as the oxidizers, but many are much larger. Some are more than 10,000 times as large as an oxygen molecule. So they can make up for low numbers with pure brawn. That is not to say that the reducers do not have small but potent soldiers. The antioxidant vitamins, like vitamin C, for example, are small but extremely potent reducing agents. The reducers also number on their side some inorganic compounds, such as ammonia, iodide, and a really nasty fellow, sulfide.

The reducers come from fish food, metabolic waste products, the breakdown of dead organisms, and certain additives put into the aquarium (e.g., iron supplements that contain ferrous ion). The surfaces of most organisms themselves enter the fray as reducers, waiting to be oxidized by the enemy.

Interestingly, most soldiers on both sides are suicide attackers. Oxygen, ozone, and hydrogen peroxide are all destroyed when they react with a reducer. While not strictly suicidal, most organics are heavily damaged by oxidizer attacks, and are slowly degraded, eventually ending up as carbon dioxide if oxidized enough. They tend to be found in areas that the oxidizers hate; that is, in areas of low oxygen. Yet, the reducers are also sneaky, and even manage to get their hands inside cells (even finding positions in photosynthesis itself).

So where does ORP fit into all this?

ORP is a measure of the relative fighting ability of the oxidizers and the reducers. Think of the surface of the ORP electrode as a surface that these various fighters are hurling themselves against for practice. If there are lots of potent oxidizers around, and not so many reducers, ORP rises because the electrode senses more oxidizing "power" in solution. Likewise, ORP drops if it senses more reducing power in solution.

The exact value reported by an ORP electrode is, consequently, a constantly varying number that represents the ebb and flow of the battle. If you add oxidizers to the aquarium (ozone, permanganate, hydrogen peroxide, etc.) then the ORP rises. Alternatively, if you add a lot of organic molecules to the solution, or restrict the oxygen supply, the ORP drops.

What about pH? pH can impact the ORP readings in aquaria. Often, ORP goes down as pH rises. A typical aquarium ORP reading will change on the order of 59 mv/pH unit. The easiest way to understand this is to simply think of pH as a measure of hydrogen ions (H+) in solution, and to think of H+ as being on the side of the oxidizers. In reality, H+ doesn't usually oxidize things itself (though it can), but more typically it can hype up other oxidizers, like oxygen, making them much more potent. So during the course of a 24-hour day in a reef aquarium, ORP will vary as pH and O2 also vary.

Is ORP a useful measure? That is, should aquarists really care how this incredible battle is going? To some extent, yes. If the oxidizers carry the day, the ORP would rise to the point where the organic molecules that represent the bodies of organisms would be burned away. If the reducers won outright, the ORP would drop below 0 mv. In that case, there would be little oxygen left, and toxic hydrogen sulfide would rule the aquarium. In either case, the aquarium would be a disaster.

So aquarists have to hope for, and to some extent maintain, this battle in a sort of middle ground. That middle ground is typically described as being between 200 and 500 mv. Most aquarium authors have recommended a range of 300-450 mV. Why? Mostly because the ocean often has ORP in this range, and because these authors have successfully operated aquaria in this range.

HOWEVER, there is a significant potential to misunderstand cause and effect with ORP. If a crappy looking tank that is overrun by algae has a low ORP, is the low ORP the cause of the algae, or is the algae the cause of the low ORP? Or are both simply the byproduct of some other process? Does artificially raising ORP by adding an oxidizer like ozone actually improve anything? The answers are not obvious. These and other related questions will be addressed in greater detail in subsequent sections of this article that go into the scientific details surrounding ORP in aquaria.

Most reef aquarists, aside from those that use ozone and must therefore monitor ORP to prevent overdosing, use ORP to monitor if anything unusual happens in the aquarium. A sudden drop in ORP, for example, suggests that the reducers are suddenly gaining ground. That might be because a gush of organic molecules has been released from a dead organism, or because the oxygen supply is not keeping up with demand for some reason. Aquarists might use such information like an alarm suggesting the tank needs to be looked at closely. Most aquarists do not target any specific ORP value as being optimal, in part because ORP measurement is subject to considerable potential error.

So is ORP measurement and control recommended for nonscientists who also happen to be reef aquarists? My suggestion is no. There are interesting things to learn by measuring ORP, and I recommend that everyone with any interest read the following sections to better understand it and decide for themselves if it is worth doing or not. Nevertheless, I have not measured ORP in my aquarium for years, despite having the tools at hand. It is simply not very high on the list of things that one can usefully do to maintain a high quality reef aquarium, in my opinion.

Amazing article. Thanks so much

 

[Paul B]

Simplified ORP

Randy, I am glad that was the simplified version. Thank you.

That is the reason that except for a very few years I have always used Ozone. Now lately I use a small Ozonizer (50 mg/hr) but for probably 40 years , I used double that amount.

I have never used a probe to regulate it because it (or carbon) was always used in a very large skimmer. I know that if I don't smell Ozone, it is not to much. As you know I am a simple man and don't do technology well and prefer to depend on common sense and my eyes, nose and the fact that my fish and tank seem immortal.

I feel, as you said in your "short" summary that it is better to have a bit more oxidizers than reducers. I got that from "Advanced Chemistry for Advanced Aquarists, Guido Huckstead". I am an electrician so I am not sure exactly what is going on there unless I see sparks.
But I know what works and if it has worked for a lifetime, I will keep using it.

 

[Randy Holmes-Farley]

Amazing article. Thanks so much

You're welcome.

Happy reefing.