Reasons for Doing Water Changes?

[TbyZ]

1. To reduce NO3 & PO4 . . . . . . . . . . (obsolete)

2. To reduce DOC . . . . . . . . . . . . . . . . (activated carbon, sponges, bacteria)

3. To replenish elements including trace elements . . . . . (balling dosing)

Are there any other genuine reasons to do water changes, specifically for water quality?

 

[reeferfoxx]

2. To reduce DOC . . . . . . . . . . . . . . . . (activated carbon, sponges, bacteria)

To reduce docs that gac and purigen cant remove

 

[erk]

Water changes are still a great method of reducing high NO3 and PO4. In the cases where you have mass die off or accidentally make a mistake during feeding etc. No other method will reduce NO3 or PO4 as quickly.

I've never heard of the acronym DOC.

You could do balling dosing, dutch synthetic, triton, zeovit, etc to replenish trace elements, but in smaller tanks, probably sub 100 gals, it really isn't feasible. You are probably adding amounts that are difficult to measure accurately. So if you did decide to dose trace elements to avoid water changes, you'd probably be forced to do the occasional water change just to bring the element levels back into balance due to constant over dosing.

I'd say even large tanks are not immune to this to a certain extent, but since they are larger you have more time and options to address imbalances.

So to say there are no good reasons to do water changes is incorrect. There are many reasons to still do water changes. It just might be that you, personally, no longer need to do water changes.

 

[TbyZ]

Water changes are still a great method of reducing high NO3 and PO4. In the cases where you have mass die off or accidentally make a mistake during feeding etc. No other method will reduce NO3 or PO4 as quickly.

I've never heard of the acronym DOC.

You could do balling dosing, dutch synthetic, triton, zeovit, etc to replenish trace elements, but in smaller tanks, probably sub 100 gals, it really isn't feasible. You are probably adding amounts that are difficult to measure accurately. So if you did decide to dose trace elements to avoid water changes, you'd probably be forced to do the occasional water change just to bring the element levels back into balance due to constant over dosing.

I'd say even large tanks are not immune to this to a certain extent, but since they are larger you have more time and options to address imbalances.

So to say there are no good reasons to do water changes is incorrect. There are many reasons to still do water changes. It just might be that you, personally, no longer need to do water changes.

I didn't say "there are no good reasons to do water changes"!

I'm asking if there are any other reasons to do them apart from the reasons i stated, specifically for normal maintenance.

You raised a good point in reference to small tanks.

DOC = Disolved Organic Compounds

 

[TbyZ]

To reduce docs that gac and purigen cant remove

Are there any DOCs that GAC or purigen don't remove? Is there any good anaylsis to back your assertion.
I would be interested in reading it if you can post a link, thanks.

 

[reeferfoxx]

Is there any good anaylsis to back your assertion

Cyanobacteria thrives on docs GAC and Purigen wont cure it. I can back that assertion. Let's see what Randy says?

 

[TbyZ]

You could do balling dosing, dutch synthetic, triton, zeovit, etc to replenish trace elements, but in smaller tanks, probably sub 100 gals, it really isn't feasible.

It is very feasible. I have a 46 gal & auto dose Aqua Forest components 1 2 & 3. Ionically balanced with all the major, minor & trace elements.

 

[TbyZ]

Cyanobacteria thrives on docs GAC and Purigen wont cure it. I can back that assertion. Let's see what Randy says?

Perhaps you used an unsuitable gac.
ROX 8 is very good. I have never had a cyano problem so i don't know really.

 

[TbyZ]

Cyanobacteria thrives on docs GAC and Purigen wont cure it. I can back that assertion. Let's see what Randy says?

Heterotrophic organisms living in a cryptic refugium, such as sponges & bivalves filter the water of DOC & bacterioplankton.
I am thinking of adding some oysters to my cryptic refugium?

Will have to research it more

 

[TbyZ]

I came across this article which I've only browsed over so far
Element cycling on tropical coral reefs Goeij, Jasper Merijn de
http://www.rug.nl/research/portal/fi...letethesis.pdf

or

https://www.researchgate.net/public...coral_reefs_the_cryptic_carbon_shunt_revealed

thinking about a combination of nutrient cycling & nutrient export methods

 

[TbyZ]

Let's see what Randy says?

 

[roberthu526]

To make myself feel better....

 

[Randy Holmes-Farley]

Are there any DOCs that GAC or purigen don't remove? Is there any good anaylsis to back your assertion.
I would be interested in reading it if you can post a link, thanks.

Certainly there are. Very hydrophilic or small molecules. Many uncharged molecules, etc. Are they a substantial issue? Not sure.

While it isn't likely an issue, molecules such as small sugars, alcohols, etc.

 

[Randy Holmes-Farley]

Water Changes in Reef Aquaria by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2005-10/rhf/index.php

Conclusion
Water changes are a good way to help control certain processes that serve to drive reef aquarium water away from its starting purity. Some things build up in certain situations (organics, certain metals, sodium, chloride, nitrate, phosphate, sulfate, etc.), and some things become depleted (calcium, magnesium, alkalinity, strontium, silica, etc.). Water changes can serve to help correct these imbalances, and in some cases may be the best way to deal with them. Water changes of 15-30% per month (whether carried out once a month, daily or continuously) have been shown in the graphs above to be useful in moderating the drift of these different seawater components from starting levels. For most reef aquaria, I recommend such changes as good aquarium husbandry. In general, the more the better, if carried out appropriately, and if the new salt water is of appropriate quality.

Calcium and alkalinity, being rapidly depleted in most reef aquaria, are not well controlled, or even significantly impacted by such small water changes. In order to maintain them with no other supplements, changes on the order of 30-50% PER DAY would be required. Nevertheless, that option may still be a good choice for very small aquaria, especially if the changes are slow and automatic.

 

[TbyZ]

I'd like to point out that Triton is the official sponser of this chemistry forum, & Triton is a no water change method.
Perhaps someone from Triton might like to offer their opinion on the matter?

 

[ReefBeta]

I'm just not 100% confident that we 100% understand what's going on in the water. ICP test tells you the composition of elements in the water, and you dose based on that. But what about the organic compounds? They all come out as carbon and oxygen molecule under the test. We don't know what's accumulated in the tank that might have negative impact long term.

Also what's our understanding of each of the elements concentration level in regards to health of the aquarium? I don't think anyone is trying to match the exact level of every elements in the seawater, all elements have kind of a wriggle room. But what's the study to determine how much of a wriggle room is OK for each elements?

To be clear, I don't mean the method of no water changes won't work. There are enough successful tank to proof that. I just don't think it's capable of 100% resetting water condition as water change will do. Probably close enough though.

 

[TbyZ]

Some things build up in certain situations

nitrate, phosphate >>>> Should no longer be a problem. Various methods of filtration have actually created the need to dose these molecules.
certain metals >>>>>>> Significantly removed via algae growth and harvesting, for example.
sodium, chloride >>>>> Will not occur if using a calcium reactor, kalkwasser or ionically balanced suppliments. ICP tests are now available to get exact figures on all major, minor & trace elements.
sulfate >>>>>>>>>>>> Occurs if using magnesium sulfate rather than magnesium chloride.

organics ????
virulent water column bacteria ????

It seems that the only good reason to do water changes, still, is for things that are not measurable at home - DOC, especially possible toxic forms, & virulent water column bacteria.

DOCs are certainly taken up by activated carbon, purigen, skimming & bacteria. But coelobite organisms such as sponges, tunicates, bryozoans, bivalves, and polychaetes, living in cryptic zones within a reef structure, take up & process massive amounts of DOCs & bacterioplankton. These types of organisms would exist in the display tank of a mature aquarium system to some degree. These types of organisms, introduced into a cryptic refugium, would be very effective at filtering - cycling & processing, these organics, I would be sure.

For those interested https://www.researchgate.net/public...coral_reefs_the_cryptic_carbon_shunt_revealed

click on - Download full-text PDF, for easier to read layout.

 

[radiata]

I'd like to point out that Triton is the official sponser of this chemistry forum, & Triton is a no water change method.
Perhaps someone from Triton might like to offer their opinion on the matter?

I think it would be more fair to say that "Triton is hopefully a no water change method." If your Triton lab results say that Component X is one third that of NSW, then you simply add more of Component X to your system. But, if their lab results say that Component Z is three times that of NSW, then you need to perform multiple water changes in order to get Component Z back into line, right?

 

[MnFish1]

Are there any DOCs that GAC or purigen don't remove? Is there any good anaylsis to back your assertion.
I would be interested in reading it if you can post a link, thanks.

How would anyone be able to answer this question?

 

[TbyZ]

I think it would be more fair to say that "Triton is hopefully a no water change method." If your Triton lab results say that Component X is one third that of NSW, then you simply add more of Component X to your system. But, if their lab results say that Component Z is three times that of NSW, then you need to perform multiple water changes in order to get Component Z back into line, right?

Yes; but (a) that's not doing 'regular water changes' ie, its a one off water change, & (b) a lack of, or, an abundance of "Z" wouldn't necessarily be due to either doing water changes or not doing water changes.