Why are waterchanges necassary?

[Sillyfishies]

My dad and sister (who works at a zoo) is convinced that waterchanges are not needed in saltwater. I was thinking that in a planted FW tank you have to waterchange (even if u has 0 nitrites) because they need the minerals in tap water.

So if you have 0 nitrates in saltwater, why do you need waterchanges?

 

[JonathanG]

In a reef you do water changes to replenish the calcium and other trace elements that corals use up.

 

[Sillyfishies]

In a reef you do water changes to replenish the calcium and other trace elements that corals use up.

What about a FOWLR?

 

[Kristy3693]

Export excess nutrients.

 

[jeffaquarius]

In FOWLR if you can maintain the parameter to be ideal such as 0 nitrate then you don't need water changes. However, it is unlikely that a tank can have 0 nitrate for a long period. At some point the inhabitants waste product would turn into nitrate unless you have all the expensive equipment that can process to remove it.

 

[Bige]

As stated above, water changes are used to export nutrients and replenish minerals and calcium and alk and mg. But there are ways around this. They just cost money. Water changes are the most inexpensive (up front cost) way to maintain a saltwater tank. Also the best way to maintain natural sea water parameters without expensive toys. But if your asking, you should do water changes. There is a lot more to this question then are water changes needed.

 

[Mebbid]

I saw a great explanation on exactly this somewhere and it's really related to the small scale molecular processes. Even if you can keep ammonia, nitrite, and nitrate at 0 the overall quality of the water degrades over time in which case a water change is necessary to refresh certain biological processes. I'm certainly not explaining this in the depth that I originally red it but that is the general understanding I took away from reading it.

 

[Oscar98]

As stated above, water changes are used to export nutrients and replenish minerals and calcium and alk and mg. But there are ways around this. They just cost money. Water changes are the most inexpensive (up front cost) way to maintain a saltwater tank. Also the best way to maintain natural sea water parameters without expensive toys. But if your asking, you should do water changes. There is a lot more to this question then are water changes needed.

Well obviously theres more to this question. Like, say the sister and dad are sating water changes are not needed maybe?? Because thats what the OP said.

 

[jeffaquarius]

I saw a great explanation on exactly this somewhere and it's really related to the small scale molecular processes. Even if you can keep ammonia, nitrite, and nitrate at 0 the overall quality of the water degrades over time in which case a water change is necessary to refresh certain biological processes. I'm certainly not explaining this in the depth that I originally red it but that is the general understanding I took away from reading it.

You might be referring to mag, cal, strontom, iodine and etc. Yes corals need them but not fish.

 

[Mebbid]

You might be referring to mag, cal, strontom, iodine and etc. Yes corals need them but not fish.

Nope, not at all what I meant.

Here is an excerpt from what I read.

Water Changes in the Aquarium
"Water changes do two things simultaneously. Most importantly they remove all the bad things that build up in the aquarium over time. These things include nitrate, phosphate, growth inhibiting hormones that many if not most fish give off, dissolved organic compounds, and other things. Although nitrate is far from the only bad thing that builds up, or even the worse, in unplanted tanks it does correlate very well with all of the other things that build up. This is why so many people make such a big issue out of nitrate. The other things are at least as important, we just don't have test kits for them (except phosphate). The other major function of water changes is to bring in good things that are used up over time. The end result of all the biological activity in an aquarium is acidification. This uses up the KH in the water. As the KH isused up the pH wil decrease. Eventually the pH can crash. There are many other vital minerals and trace elements needed that are replenished with water changes.

Water changes also have a massive impact on stocking. It is an error to discuss stocking without addressing water changes and water quality. Discussing stocking based on tank size alone is not different then simply going by one of the very errored 'one inch per gallon' type guides. Experiments have shown that it is the water quality, not tank volume, that stunts fish. Discus were raised in two different setups. One was a twenty gallon tank that was heavily stocked and received very large daily water changes. The other setup was a fifty five gallon tank with a small fraction of the number of fish and did not receive any water changes. The discus in the twenty gallon grew at a normal rate while those grown in the fifty five were severely stunted. The experiences of many other aquarists support the results of this experiment, demonstrating that it is definitely water quality, not volume, that is the active factor in stunting fish. Obviously there is still a minimum tank size for fish based on size and activity leve. Please see the Stocking an Aquarium article for more information. The volume of the tank has a minimal impact on water quality."

 

[jeffaquarius]

Now that's a great info that no one can argue lol

 

[Sillyfishies]

Nope, not at all what I meant.

Here is an excerpt from what I read.

Water Changes in the Aquarium
"Water changes do two things simultaneously. Most importantly they remove all the bad things that build up in the aquarium over time. These things include nitrate, phosphate, growth inhibiting hormones that many if not most fish give off, dissolved organic compounds, and other things. Although nitrate is far from the only bad thing that builds up, or even the worse, in unplanted tanks it does correlate very well with all of the other things that build up. This is why so many people make such a big issue out of nitrate. The other things are at least as important, we just don't have test kits for them (except phosphate). The other major function of water changes is to bring in good things that are used up over time. The end result of all the biological activity in an aquarium is acidification. This uses up the KH in the water. As the KH isused up the pH wil decrease. Eventually the pH can crash. There are many other vital minerals and trace elements needed that are replenished with water changes.

Water changes also have a massive impact on stocking. It is an error to discuss stocking without addressing water changes and water quality. Discussing stocking based on tank size alone is not different then simply going by one of the very errored 'one inch per gallon' type guides. Experiments have shown that it is the water quality, not tank volume, that stunts fish. Discus were raised in two different setups. One was a twenty gallon tank that was heavily stocked and received very large daily water changes. The other setup was a fifty five gallon tank with a small fraction of the number of fish and did not receive any water changes. The discus in the twenty gallon grew at a normal rate while those grown in the fifty five were severely stunted. The experiences of many other aquarists support the results of this experiment, demonstrating that it is definitely water quality, not volume, that is the active factor in stunting fish. Obviously there is still a minimum tank size for fish based on size and activity leve. Please see the Stocking an Aquarium article for more information. The volume of the tank has a minimal impact on water quality."

I'm 99% sure that's for freshwater...

I just find it funny that the zoo does monthly 30% waterchanges on their shark tank, but none of the other tanks.

 

[jeffaquarius]

My dad and sister (who works at a zoo) is convinced that waterchanges are not needed in saltwater. I was thinking that in a planted FW tank you have to waterchange (even if u has 0 nitrites) because they need the minerals in tap water.

So if you have 0 nitrates in saltwater, why do you need waterchanges?

I thought your question is for salt water. Zoos and large aquarium may have all the equipment to maintain the water quality and do not need water changes. It also depends on how hardy the fish are like the shark.

 

[Sillyfishies]

I thought your question is for salt water. Zoos and large aquarium may have all the equipment to maintain the water quality and do not need water changes. It also depends on how hardy the fish are like the shark.

It is for saltwater. I was just saying that in freshwater even though your nitrates are 0 you have to do waterchanges.

 

[Mebbid]

I'm 99% sure that's for freshwater...

I just find it funny that the zoo does monthly 30% waterchanges on their shark tank, but none of the other tanks.

It's for both salt water and fresh water. The chemistry is the same regardless of whether there is a higher specific gravity or not.

 

[Sillyfishies]

It's for both salt water and fresh water. The chemistry is the same regardless of whether there is a higher specific gravity or not.

But saltwater fish don't need the minerals in tap water like freshwater fish do.

 

[aquandrew]

But saltwater fish don't need the minerals in tap water like freshwater fish do.

fish may not, but corals sure do. not tap water, but the minerals being replaced

 

[Mebbid]

But saltwater fish don't need the minerals in tap water like freshwater fish do.

If you read my earlier post concerning this you would understand that I'm not talking about replenishing minerals. Fish secrete a growth stunting hormone into the water which will directly cause them to grow slower and cause issues related to stunted growth. That along with the increasing acidification from the beneficial bacteria means that tanks need water changes.

 

[Sillyfishies]

If you read my earlier post concerning this you would understand that I'm not talking about replenishing minerals. Fish secrete a growth stunting hormone into the water which will directly cause them to grow slower and cause issues related to stunted growth. That along with the increasing acidification from the beneficial bacteria means that tanks need water changes.

Then I don't see how the zoo has had 30+ tanks running for 10 years without a waterchange. And all the tanks look fine to me. Fish are healthy.

 

[Bectan01]

How big are these tanks at the zoo and what so they have in them? What type of filtration are they using? A closed system in the home is surely a very different thing than zoo aquariums. I have seen large aquariums at city zoos that pump natural seawater into them, so I can't imagine they would be doing water changes as such, different ball game I reckon