TDS discussion

[Caliban07]

I've been at this hobby for a second time round for a little over a year now. With the help of this forum and copious amounts of research I'm finally at a place where I am happy with my tanks.....no more stress! Yippee!

Anyway, there has been one topic that has been playing on my mind for quite some time. Total dissolved solids.

We all know about the osmoregulatory system to a certain extent. Not so much the nitty gritty as far a how certain things in our tap water effect out fish. Without being scientists we are never going to know how boron for example effects the fishes physiological well being on a cellular level but we know TDS is there and it IS important.

This is why we acclimate fish so they have time to adjust so that the effect of Change in water is not say sudden one overwhelming the fishes cells etc.

We try to achieve certain water chemistry for certain fish and are happy that farm bred fish can be quite hardy and can adapt to most water chemistries if we adjust them slowly.

What my worry is forever rising TDS. With the things we put in to our aquarium such as food, fertilisers etc and the obvious slow evaporation it is inevitable that TDS WILL rise. This rise will vary for everyone's aquarium. The things we add, the amount we lose and the amount we change.

Now even if this change in water chemistry is ever so slight and may take a long time to rise the fact of the matter is is that it is still rising. Correct me if I am wrong but if the TDS of our water is always changing (rising) then this must be having a slow effect on our fish. Even though they are always adapting would it not make sense that this change is costing them small amounts of energy day by day in order to compensate for the new change? Could this be causing underlying physiological changes to our fish that will go unnoticed until the fish becomes ill?

Could this be the reason why some fish become ill or die for no apparent reason. Some fish no matter what species will feel this more than others just like you or me react differently to temperature.

I want to hear your thoughts on this topic and if you share this worry.


Thanks

 

[UABsleeperSRNA]

Soooo That's an interesting question and not one i am familiar with particularly are you taking into account we are cutting in half the amnt of TDS if were to do a 50 % Water change if so what's your thoughts on that related to this theory??

I know a moderate amount about human physiology and and dissolved substances.. and i believe it would relate somewhat.. i think a lot of TDS affect on fish would have to do with what material your talking about and it's ionic make up i know in humans ionic substance in the bloodstream for the most part most part ionized materials must have channels or membrane bound carrier proteins to transport specific ions across membranes (depending of course where your talking about) but small unionized substances can readily pass from areas of higher concentration to lower concentration.. and i assume it's the same with fish..

That's based on the assumption that Free Ammonia or NH3(unionized) can readily pass through their membrane where as NH4+(ionized) is not toxic to fish and cannot pass through their membranes

Ithink it would also depend on the molecular size of the compound nitrite is ionized and so is Nitrate but Nitrite is much more toxic b/c it readily passes into the through their membrane into their blood stream.. and again another assumption would be b/c nitrite is 40g/mol and nitrate is 62g/mol so i know that would also play a role and i guess it is like humans would have to do with age..

I would agree prolonged exposure to toxic chemicals we add to the water or fail to remove from the water.. could result in fish death in the long term.. my thought's related to humans again.. as we age our body and our genetic make up is the sum of our environment like smoking for example prolonged exposure to toxic chemicals can interfere with cellular DNA synthesis resulting and transposition in parts of DNA strands or deletion the cells that are produced are usually detected and destroyed my our immune system but this is not always the case.. as we age however the number of mutations(oncogene) begin to build up and bam cancer or illness .. .. and this probably the same with fish i assume prolonged exposure to chemicals probably results in mutations further down the road with repeated exposure.. and eventually leads to compromised cellular function and and death from illness ect..

HA just my thoughts on it i do however think that by changing our water we decrease the amount of these toxic materials improving the length of life and health of our fish! Just my thoughts from a medical background

 

[Caliban07]

Forgive me for not quoting you in this reply. My phone doesn't like it when the post is too long.

You are thinking along the same lines as me in terms of how each and every molecule absorbed by the fish effects it in the long run. Like you say, smoking for example. If all these toxins are trying to be combatted through out immune system, does this not increase our energy dispersion somewhat on a cellular level making us feel more tired. Not to mention the physiological effects of the toxins directly on our organs.

I know TDS can effect organs such as the kidney but it could also be having a knock on effect on other things too. Without being an aquatic biologist I'm never going to know exactly how the makeup of our tap water effects the fish.

My main concern is the osmoregulatory system and the extra work it has to do in order to compensate for rising or fluctuating TDS levels. I think this is more serious than we think.

I would agree that if you were changing out 50% with water that was void of TDS then this would reduce it but we are adding TDS from back in from our tap. Adding ferts, food and TDS left behind through small amounts of evaporation would lead to an inevitable rise.

In order to reduce it you would have to start cutting the new added tap water with RODI water and even this would take a long time.

How many people actually do 50% a week? And how many do it every week?

Changing 100% of the water of course would do it but I you are just introducing changes that you are trying to avoid no?

What do you think?

 

[Caliban07]

I'm just thinking...even LOWERING the TDS slowly will force the cells to react differently to achieve a new balance thus using energy.

My understanding of the osmo system is that a balance is never truly achieved since the water is constantly changing all the time but as long as the TDS doesn't drift out of range for the species then everything will be ok and the fish should live to it's life expectancy.

Even if farm bred neons are bred in hard water with a ph of 8. Surely they would still benefit from soft water as it's still in the species gene pool.

I'm not sure where I'm going with this yet. Get me back on track!

 

[UABsleeperSRNA]

ha sorry i'm of no use right now.. my mind just got assaulted by one of our exams! haha i will take a look at your comments this evening when my mind has had a little time to recover and i can comprehend what you have written haha

 

[aqua_chem]

So, your thought is that the increased metabolic demand of this 'TDS creep' is going to place the fish in undue stress?

If that's the sum of it, I don't think you necessarily have much to worry about. Relative to the total metabolic demands of the fish, the expenditure of the fish's gills/kidneys (I believe most of the ion balance work is done by the gills in fish, may be confused on this point) is probably non-trivial, but ultimately not going to be a problem in a well-fed aquarium fish.

Second, it's important to note that the TDS creep of most tanks is going to be slight, especially if you're just feeding fish. There are a few things that you can do to increase it faster, such as aquarium ferts, leeching rocks, water softeners, or non-DI topoffs, but overall it's not going to be that much different in the long run.

I do see two fish health related consequences of TDS though. The first is the classic 'old tank syndrome' that you sometimes hear about, wherein a tank that hasn't had it's water changed in months is suddenly cleaned (including a larger water change), and a bunch of fish die. This is likely due to TDS/pH factors, as the tank had been topped off with tap water for months, slowly increasing it until it was significantly greater than the tap, then the sudden change in conditions when you replace most of the water with tap water causes an overload in the homeostatic mechanisms of the fish, leading to tissue damage or death. The other would be in classically soft water (or hard water) fish that are subjected to an increase in TDS well beyond what they naturally would have experienced. In that case, their natural regulatory mechanisms might not be able to 'rev up' enough to meet these demands, resulting in their death as well.

Food for thought.

 

[Autumnsky]

Thank you aqua_chem. Always a learning experience.

 

[Caliban07]

Again sorry I can't quote but to aqua chem. I was under the impression that the osmoregulatory system was regulating the transfer of fluids between cell membranes depending on the salt concentration internal/external to the cell. Water constantly rushing in and out of the cell until a balance of a fashion is achieved? This process is what requires a high metabolic demand.

Do you not agree that even if the TDS is ever so slight it is still creeping all the same. How many people just feed fish these days? With so many chemicals on the market i think just adding food is a thing of the past.

Even if you hang back on your water change for 3 days. That creep has just shifted again by 3 days worth of minute TDS rise. If the happens throughout the course of a year or two how much would this rise? If you still don't thing it's is enough then I will concede but all I'm saying is that we all do things differently and some TDS will creep faster than others. Especially in warmer countries where top offs are daily.

How do you feel about water changes of over 50% in a tank that has been sat for a week with top off and ferts food etc. would you agree this sudden change to water chemistry is not healthy for the fish. Maybe not the once but collectively if practised weekly.

What about people with plants that don't gravel vac. Will this increase TDS faster?

I heard TDS enters the water naturally through the atmosphere too. Is this true?

 

[jetajockey]

I would imagine that a tank that has only been a week or two between water changes wouldn't be all that drastic of a change.

I think your basis assumes that minute, or even small changes in TDS are harmful to fish and they don't have the adaptive capability to deal with it.

All I know is I find fish in some really really high TDS areas. Even in the water with the consistency of soup, fish thrive. I've never tested the TDS to get an exact number, but maybe I should sometime to get an idea. I've tested the pH in some of these swampy backwaters and I've seen it down into the 3s. When it rains, there's a potential for a huge shift in TDS in smaller bodies of water, so that would lead me to believe that at least most of the fish can handle it to some degree.

 

[Caliban07]

I would imagine that a tank that has only been a week or two between water changes wouldn't be all that drastic of a change.

I think your basis assumes that minute, or even small changes in TDS are harmful to fish and they don't have the adaptive capability to deal with it.

All I know is I find fish in some really really high TDS areas. Even in the water with the consistency of soup, fish thrive. I've never tested the TDS to get an exact number, but maybe I should sometime to get an idea. I've tested the pH in some of these swampy backwaters and I've seen it down into the 3s. When it rains, there's a potential for a huge shift in TDS in smaller bodies of water, so that would lead me to believe that at least most of the fish can handle it to some degree.

Of course fish have the adaptive capability to deal with changes to their environment. My questions are centred around the physiological affect it has on them in order to do this every time there is a fluctuation in TDS or constant adaptation to creeping TDS.

Did the first school of fish born in to these swaps with low ph survive? Probably not. These fish would have had to alter their genetic makeup over many of years to be able to thrive in these waters and handle large fluctuations in parameters.

Maybe it depends on the fish, the species and where they were sourced and how they were raised. I sometimes wonder whether although acclimatised as best we can, the fish goes through some changes to its physiological processes as it cells adapt to the new concentration of salt/water ratio between cells and the new reduced or elevated mineral content of the water that effectively stresses the fish. The fish becomes ill and we wished we'd have quarantined because this fish was always carrying a disease when in actual fact it wasn't.

I'm only asking for thoughts. It's a discussion after all.

 

[BillD]

I believe that big differences in TDS is what is behind the "pH shock" myth. However, there are areas of the world where there is wildly fluctuating water levels caused by rain. While this happens once a year in the Amazon, where many of the waters are soft, this is not the case in places like Costa Rica where river levels can rise more than 30 feet in a day and may happen monthly. You would think that TDS would fluctuate widely in this scenario. The fish seem to have adapted to this, so, perhaps there may be more leeway than we think.

 

[Caliban07]

I believe that big differences in TDS is what is behind the "pH shock" myth. However, there are areas of the world where there is wildly fluctuating water levels caused by rain. While this happens once a year in the Amazon, where many of the waters are soft, this is not the case in places like Costa Rica where river levels can rise more than 30 feet in a day and may happen monthly. You would think that TDS would fluctuate widely in this scenario. The fish seem to have adapted to this, so, perhaps there may be more leeway than we think.

I suppose TDS does fluctuate somewhat in the wild. If rivers in costa rica were rising 30 ft due to heavy rain, you would expect the TDS to be diluted provided the rain was void of minerals. As the water level rises and engulfs the land more TDS would be collected would there be such a drastic swing?

Perhaps we should focus more on farm bred fish that are housed in a small tank where we control their environment.

If fish are capable of handling this large fluctuations why do we focus so much on acclimatising?

I'm not trying to be clever here I'm simply asking questions that have been on my mind.

 

[Delapool]

I wonder if our fish are used to acclimatising? My tap water is quite clean I guess compared to other places which I'm just not used to. I wonder if store fish are just not used to changing conditions? On the flip side I guess plenty of released pet fish have survived in the wild.

 

[BillD]

Indeed, while what happens in the wild may not be what happens in our tanks, it does give me pause. I don't spend much time acclimatizing fish when I get them. Most of the time they come from basically the same water that comes from my tap, so I don't see a need. I don't keep anything truly exotic that would require specialized water treatment. I am far too lazy for that. As Dr. Paul Loiselle said when he spoke at our club, fish either like his water or he moves them on. I have no interest in playing water chemist. So far it has worked for me, on and off for about 50 years.

 

[Mama Karoti]

If you are topping off with RO or distilled water to offset evaporation, this will not happen.

 

[aqua_chem]

Another way to think about it is with a human analogy. While humans don't need to deal with an external environment to the same degree a fish would, we still need to regulate our internal environment. Let's say you eat a lunch consisting only of salt and vinegar potato chips, extra salt, no water. The result of that is an increase in your body's sodium load, which will draw water into your circulatory system and making your internal 'TDS' higher. You body senses this, and your kidneys kick into gear by excreting the sodium again via urine. Now, does your poor choice in lunch cause your body to expend additional energy to maintain homeostasis? You bet. But are you going to miss it? Not really. Similarly for fish, it is going to cost them some energy to maintain and adjust to new water chemistry, but they're not exactly hurting for energy considering that you could feed your fish every three days but many do it daily.

 

[aqua_chem]

Do you not agree that even if the TDS is ever so slight it is still creeping all the same (Agree) . How many people just feed fish these days? With so many chemicals on the market i think just adding food is a thing of the past.


Even if you hang back on your water change for 3 days. That creep has just shifted again by 3 days worth of minute TDS rise. If the happens throughout the course of a year or two how much would this rise? If you still don't thing it's is enough then I will concede but all I'm saying is that we all do things differently and some TDS will creep faster than others. Especially in warmer countries where top offs are daily.

I live in Denver. It's pretty dry and low pressure, both of which increase evaporation (at least compared to Washington where I grew up). I easily top off 4 gallon a week in my 40B with tap water to keep levels stable. That's about a 10% increase in osmolarity just from me topping off. I don't consider it a problem.

However, when I was studying for boards I didn't change my water for waaaay to long, probably two months or so. It was a bad time. There weren't any fish in that tank, so I wasn't too worried about it. When I finally did change the water, it melted my entire dwarf baby tears carpet I had been growing. If plants blanched that bad, fish would probably have it worse. That being said, they were doing fine at much higher TDS levels until I decide to perturb the system because it was brought up slowly.

How do you feel about water changes of over 50% in a tank that has been sat for a week with top off and ferts food etc. would you agree this sudden change to water chemistry is not healthy for the fish. Maybe not the once but collectively if practised weekly.

Standard procedure of EI plant dosing, wouldn't bat an eye. I've done it for years, as have many.

What about people with plants that don't gravel vac. Will this increase TDS faster?

Probably not significantly. We're probably starting to get into insignificancies of insignificancies at this point though.

I heard TDS enters the water naturally through the atmosphere too. Is this true?

No. If there is any truth to it, it completely happen in the first few hours out of the tap, not over the course of days/week. But as I said, I have no idea what this is talking about.

Maybe it depends on the fish, the species and where they were sourced and how they were raised. I sometimes wonder whether although acclimatised as best we can, the fish goes through some changes to its physiological processes as it cells adapt to the new concentration of salt/water ratio between cells and the new reduced or elevated mineral content of the water that effectively stresses the fish. The fish becomes ill and we wished we'd have quarantined because this fish was always carrying a disease when in actual fact it wasn't.

If the surrounding environment is dramatically different enough to alter the fish's intracellular/extracellular environment, something has already gone horribly wrong and the fish's regulatory machinery is being overwhelmed.

There's actually a school of thought on acclimation that essentially says you can just dump a fish directly into an aquarium and call it good. The logic being that any physiologic adaptation that they're going to do is actually going to take place of the course of several hours/days/weeks rather than the minutes we usually spend on acclimating, so anything else is just wasting time. The idea has some merit, with the concept being similar to how humans acclimate to high altitude. I'm just not willing to test it on my fish, that's for sure.

 

[Caliban07]

Ok so TDS isn't really that big a deal to worry about. Unless the tank has received no water changes for a long time. The fact that your plants melted could have been down to other things though so not directly TDS related.

If I are potato chips everyday and drank less water everyday I would definitely become ill. Rather like drinking sea water.

I see a lot of fish dying on here post water changes and I thought this may have been one of the reasons.

I still believe that it is better to change less water more often and that keeping things stable is better. Maybe fish can adapt to change but I believe they would prefer it if things were kept as stable as possible where routine was appreciated.

 

[Caliban07]

If you say that it can or does take fish hour/days/weeks to adapt this must mean that they are always adapting. This means that fish can handle these fluctuations. But there's always one. Some

There must be some species that find it more difficult.

Neons, rams, ottos all difficult fish to keep alive I've noticed. Especially wild caught.

Perhaps some deaths are not directly linked to the concentration of TDS but the molecular make up of the water itself.

A whole new route. One which I will probably never know.

 

[Autumnsky]

If you say that it can or does take fish hour/days/weeks to adapt this must mean that they are always adapting. This means that fish can handle these fluctuations. But there's always one. Some

There must be some species that find it more difficult.

Neons, rams, ottos all difficult fish to keep alive I've noticed. Especially wild caught.

Perhaps some deaths are not directly linked to the concentration of TDS but the molecular make up of the water itself.

A whole new route. One which I will probably never know.

Those fish mentioned are often wild caught and sometimes done with poison and no matter if not poisoned, the catching and travel and more travel, and more travel through brokers and middlemen cause fish to be stressed and a huge change in natural diet to flakes or pellets in contained environment not all fish are able to make the changes from a wild natural diet before the additional stresses are fixed. Some of the fish have parasites as well which would take advantage of a stressed fish to make their play for control and make the fish even more ill.

This is one benefit, trying to find locally raised fish from fellow hobbyists, fish are used to your water, and will have a bit less travel issues.

I can't even imagine how many wild caught fish die from the attempts to capture them to the time they make it to the hobbyist, and then so many more die because we don't care for them correctly or well. Some people do however and that is all the better for our shared experiences here on AA.

Asking questions is beneficial.