I don't do water changes

[vitz]

although I believe in water changes I would have to think the only reason we don't see more "anomalies" of people not doing water changes is because it isn't the norm.

we are taught from the get go that we need to do water changes.

i would be interested in hearing from people who have been in reef keeping for 20 or so plus years. key word being reef, and not saltwater fish.

my first reef tank was in 1977-ish. (i hope that qualifies ;-p )

it's my personal opinion that anyone who advocates the superiority of a totally closed system over a 'semi-closed' one is someone w/no real world experience on any appreciable scale to be able to make any statements about the merits of one over the other

as an example:

all fish produce an 'anti growth' hormone as part of their biological arsenal to foster the development of the first biggest growing fishes over the 'runners up. it's why fry grow in 'spurts' of a sort (e.g.-remove the 10 biggest fry, and some of the smaller fry will then 'spurt' in growth). when doing wc's, you get alot more fry 'spurting' constantly as a percentage of the whole population.

there are many other hormones that fish release into the water throughout their life, that we can't measure. that's but one very tiny example of a class of organic compounds where we don't know if they're 'sinkable' or not. to say nothing of the probable thousands of compounds produced by corals/inverts-some of which we've discovered, and some of which we know are HIGHLY toxic to other corals/inverts.



i wouldn't take a risk of a probable waste product POSSIBLY rising ad infinitum, and not knowing what the effects MIGHT be,when there's a profoundly simple way of eliminating that as a variable.

it's about doing what's most prudent, and 'covering one's butt', given our present knowledge base of what's going on.

eliminating variables and unknowns in a closed/semi-closed system is fundamentally one of the most important concepts/practices of disease prevention and control of any animal husbandry in a closed/semi closed system.

on the whole, it's been my direct experience that wc's are a preferable way to go, and nothing substitutes for something so simple that provides as much benefit all around. (assuming, of course, that the water being used has the proper parameters/quality needed, natch - this doesn't mean that various dosing and 'artificial sinking' isn't useful or improper-the best success is achieved using BOTH methodologies, together, ime/imo).

my healthiest most productive reef tank got a 90% (!) wc every week to two weeks. (w/ properly aged/mixed/adjusted sw).

constant damsel spawning, and phenomenal coral growth, in spite of keeping large leathers w/ large lps's in a relatively small (75gal) tank, along w/ nightly plankton/zooplankton/copepod/gammarid 'population explosions/blooms'. there was also dosing and skimming going on-but the tank ALWAYS looked it's best following a large wc.

i've yet to see non wc systems, as a whole, come close to wc'd systems, w/ regards to polyp expansion and overall system health (including the fish). not saying there aren't any, or that it can't be done, but wc's definitely make it easier to obtain that objective, by and large.

this is the conclusion i've come to after working w/ many different size systems-from 2.5 gallon guppy tanks, to commercial hatcheries (fw) to lfs's, and large closed system husbandry on the wholesale/import side of things.

hth

 

[vitz]

btw, i do wonder how tangs in the ocean get hlle, since no one's running carbon in the world's oceans

 

[vitz]

considering that people have been trying to get away with the no water change idea like your talking about for decades, pretty hard to consider the idea innovative

imo the no water change idea is an innovation akin to to trying to improve on the wheel...by making it square.

this

 

[billsreef]

i would be interested in hearing from people who have been in reef keeping for 20 or so plus years. key word being reef, and not saltwater fish.

:wavehand:

In addition to Vitz and myself in this thread, I know of a number of people on RC that have been doing this for 20 or so years....all that I know do routine water changes

 

[SaltWater226]

Everyone,

I have been in the fresh-water hobby for 45 years, in planted tanks since the early 80s, but in salt water such a short time that I don't own any fish or corals yet. Just a 90 gallon tank with some live rock and apitasia. :xlbirthday:

That said, I stopped doing water changes a number of years ago. And I did not stop because I am a lazy bum (although I don't deny the charge). I stopped because a water change is an admission that you are doing something wrong. A water change means your fish don't live in optimal conditions all the time, just right after the water change. A water change, especially a big one, is very stressful for the animals.

So I changed my practices so that my nitrates are never out of range, and my phosphates are never out of range, and my tank always has the micro nutrients that it needs, and therefore there is no reason to stress everybody out by doing a water change.

I use bio-remediation, denitrators, GFO reactors, activated carbon. On salt water you guys have this cool thing called a skimmer. What a great thing for getting rid of DOC! I could not be happier.

So, I know this is controversial, but I don't think a water change every week is something to be proud of.

live rock and aptasia ? why would you need water changes?

 

[odst223]

The educational qualities from Vitz and others have been phenomenal and answered alot of tank questoins I get asked at the LFS I work at. This should be stickied, if only to submit the idea of hormones in the water and so-on. Great thought!

 

[Decadence]

I don't believe that just be ause X level of X element is found in sea water, the corals actually use it. A calcium reactor should perfectly portion essential elements back into the water. As for waste, what can't be organically or chemical bound and removed?

I'm not a huge proponent for the "zero water change" crowd but I definitely don't feel that they are necessary in any regular frequency. I would prefer to only do one large water change per year.

 

[MKsreef]

I change 15 gallons in my 92 gal every week. Takes me 15 minutes and the tank has been doing well. I used to test the water every week. Not anymore, my tank has been very stable for the last six years.

 

[SantaMonica]

Speaking of trace elements, you should see the list of vitamins, amino's etc that algae put into the water.

 

[Reef Raf]

I'm trying to think of ANY living system that you'd want to keep closed? Could there be a system that you don't want open in some way. Even in the example of a fresh water system where you are not doing a water change...don't you need to replace evaporated water? I'm under the understanding that RODI water wont sustain fresh water fish over the long haul without additions of trace elements? If that is the case, then how can that be said to be a closed system entirely?

 

[Decadence]

I'm trying to think of ANY living system that you'd want to keep closed? Could there be a system that you don't want open in some way. Even in the example of a fresh water system where you are not doing a water change...don't you need to replace evaporated water? I'm under the understanding that RODI water wont sustain fresh water fish over the long haul without additions of trace elements? If that is the case, then how can that be said to be a closed system entirely?

No fish tank is a truly closed system. When water evaporates, that is open. Nitrogen gas fizzes away, open. RODI being topped off, open. Feeding, open. Supplementation... you get the point.

 

[power boat jim]

No fish tank is a truly closed system. When water evaporates, that is open. Nitrogen gas fizzes away, open. RODI being topped off, open. Feeding, open. Supplementation... you get the point.

All I need know about water changes can be summed up like this, if you left your bath water in the tub, and just added soap and replaced the evaporated water when you wanted a bath you would realize how closed the system really is. Unless you remove the water and repalce it, everything that is in solution in that water stays there.

 

[SpartaReef]

All I need know about water changes can be summed up like this, if you left your bath water in the tub, and just added soap and replaced the evaporated water when you wanted a bath you would realize how closed the system really is. Unless you remove the water and repalce it, everything that is in solution in that water stays there.

Best explanation ever...

 

[blanden.adam]

No fish tank is a truly closed system. When water evaporates, that is open. Nitrogen gas fizzes away, open. RODI being topped off, open. Feeding, open. Supplementation... you get the point.

Well sure, by definition because it interacts with the surrounding environment so it's not precisely closed, but that's really more of a technicality as the only truly closed system is the universe.

What people mean when they say that a reef tank is a "closed" system is that for the things we typically care about (nitrates, phosphates, other nutrients, calcium, alk, etc), nothing enters unless you put it there, and nothing leaves unless you take it away.

Sure, water vapor leaves without your intervention, heat energy will transfer between the stand/room air and the tank, and in the case of a DSB nitrogen can bubble away, but that's really about it. The rest requires you.

 

[Phixer]

This is simply untrue, and with a little bit of math, we can calculate where you will reach steady state at any given consumption level. In fact, I just had the same argument earlier this week, so I'll just re-post from that thread:



If we start with the assumption that our synthetic sea salts contain the appropriate elemental composition for our livestock (which I think is entirely reasonable, and if not you should pick a different salt ), and we accept that there are many things required by our livestock and that could potentially harm our livestock that we can't reliably measure for (trace elements, compounds form coral alleopathy, etc.), then a few things become plainly evident. 1) We cannot "prove" they are depleted without sophisticated laboratory equipment that can measure very small quantities of each compound reliably, 2) Even if we did that we cannot monitor all of these compounds to ensure they are within their required ranges cost effectively (i.e. we cannot reliably test for and dose them by themselves) and 3) No matter how their concentration varies while in our tank, by removing a proportion of the water and adding new synthetic sea water, we by definition move them closer to their target ranges.

Mathematical explanation. English translation below. Feel free to skip the math if you trust me or hate algebra.

With regard to your second question, lets do some math. Lets take a tank of some volume "V" and change 10% of the volume at some time interval and track what happens to our mystery trace element, call it element X.

Element X is kept at a constant level over time when the amount brought into the system by a water change is equivalent to the amount consumed between water changes plus the amount removed by the water change itself. Obviously, if the element is being consumed without replacement, it will have to achieve steady state at some concentration lower than the level found in your freshly mixed ASW (barring a 100% water change of course.) Lets say element X has a concentration "Cb" in your freshly mixed water (in the bucket) and "Cs" for the water in your system. Between water changes, your tank uses up some fraction "f" of that element in your system. We can then write the equations:

0.1*V*Cb = mass of element X added by a water change
f*Cs*V + (Cs*V - f*Cs*V)0.1 = the mass of element X consumed by the tank plus the mass of element X removed during the water change

By the law of conservation of mass and steady state assumption we get

0.1*V*Cb = f*Cs*V + (Cs * V - f*Cs*V)0.1

When solved, this leaves us with:
Cb = Cs * (9f + 1)

For explaination's sake, lets say the level in your tank is 50% of the level in your freshly mixed seawater (idk, just picking a number there).

We can then add the equation
Cs = 0.5 * Cb

Which when substituted into the above equation, leaves us with

f = 0.11

English resuming. Thanks for your cooperation

Which means a 10% water change will keep the level present in the tank constant when the amount consumed by the tank between water changes is about 11% of that found in your tank (assuming the level in your tank is at 50% of that in your bucket). Where that "steady state" happens is determined by the concentration in your salt an consumption, which is usually related to the concentration in your tank, so it gets more complicated than what I've shown based on a number of variables, but the concept is always true. I guess my point is, it's not nothing, mathematically we can see water changes have a non-trivial effect.

Finally, with regard to the statements regarding SPS tanks without water changes for years. Even if it is true, citing the exception to a rule when dealing with populations doesn't mean the rule is wrong, it just means you're citing the exception. My grandfather ate bacon and eggs every day of his life and lived to be 80 years old, completely able to move on his own and completely mentally in-tact -- that doesn't mean that bacon isn't bad for you.

Pretty cool Adam. How do you calculate rate of consumption when conditions are constantly changing? I.e, add 1 new fish Monday, add 10lbs live rock Tuesday etc... Wouldnt the change in bioload and the addition of LR affect these parameters? Probably why for many the solution to pollution is still dilution.

When an anomaly exceeds 50% does it then become the norm? :lol:

 

[ClippersTown]

All I need know about water changes can be summed up like this, if you left your bath water in the tub, and just added soap and replaced the evaporated water when you wanted a bath you would realize how closed the system really is. Unless you remove the water and repalce it, everything that is in solution in that water stays there.

I didn't read the entire thing, but if he runs a skimmer then that stuff gets removed. so it's not totally closed.

 

[blanden.adam]

Pretty cool Adam. How do you calculate rate of consumption when conditions are constantly changing? I.e, add 1 new fish Monday, add 10lbs live rock Tuesday etc... Wouldnt the change in bioload and the addition of LR affect these parameters? Probably why for many the solution to pollution is still dilution.

When an anomaly exceeds 50% does it then become the norm? :lol:

Well, rate of consumption is just the change in level over time, so delta(Level)/time. However, that we can't reliably measure most of the trace elements in a reef kinda makes that calculation impractical.

The big complicated calculation is just a back-of-the-envalope calculation do demonstrate that waterchanges at a typical level can have a significant impact on the concentration of trace elements in a reef.

And your final point is entirely correct. We cant reliably measure everything, so the solution is indeed dilution :beer:.

 

[DavidinGA]

All I need know about water changes can be summed up like this, if you left your bath water in the tub, and just added soap and replaced the evaporated water when you wanted a bath you would realize how closed the system really is. Unless you remove the water and repalce it, everything that is in solution in that water stays there.

Yeah except for all the ways nutrients (soap in your illustration) is removed other than changing out the water - skimming, algea, bacteria, mechanical, biological, gfo, etc...

Your example is a bit flawed.

 

[power boat jim]

Yeah except for all the ways nutrients (soap in your illustration) is removed other than changing out the water - skimming, algea, bacteria, mechanical, biological, gfo, etc...

Your example is a bit flawed.

Its not that those things cant be removed , they often cant be removed as fast as they build up in many cases. Also running pellets or GFO come with a risk of doing it improperly. Water changes can help fix a number of things without that risk and the effect is immediate.

The bath example isnt that flowed if you put a little thought into it.

 

[SpartaReef]

Yeah except for all the ways nutrients (soap in your illustration) is removed other than changing out the water - skimming, algea, bacteria, mechanical, biological, gfo, etc...

Your example is a bit flawed.

Gfo and other "filters" get clogged over time... What's easiest and cheaper? A water change or changing media?