Why should you do water changes?

C

CRC88

New member
So I was wondering... why should you do water changes? I understand it's the accepted wisdom in this hobby - water changes keep things stable, remove nutrients, and replenish trace elements.

HOWEVER - I have had my tank setup since July and was very consistent on water changes for the first 6 months (15% every two weeks). Then come the holiday time of year, and I haven't done one in 8 weeks. The entire time, I kept tabs on water quality. As of yesterday my numbers were:
pH: 8.4
Alk: 2.4 meq/L
Temp: 78F
Salinity: 1.025 (hydro)
Ammonia: 0
Nitrite: 0
Nitrate: 5
Phosphorus: 0
Copper: 0 (had prior issues with this)
Calcium: 420
As you can see, everything is spot on, and has been this way for the last 10 weeks without doing a water change. Just so people know my setup, all the equipment is listed in my signature, and my livestock is as follows: Two Ocellaris Clownfish, One Bicolor Blenny, One Scopas Tang, and One Blue-Green Mandarin, and three-five snails.

I'm not saying regular maintenance isn't very important, I'm just asking why must water changes be a part of the "regular routine"? I religiously clean my filter pads, empty my skimmer cup, turkey baster off the rocks and occasionally harvest macro algae all to achieve the goal of nutrient export. I also add trace elements, buffer, and check salt levels every week.

So if I replenish trace elements with a supplement, keep my nutrient levels low via Macro-algae, skimming, and blasting off the rocks, and all other parameters are in check, then what's the pressing need to do water changes? Is there some other reason that I'm missing?

Any thoughts or input is very helpful. I'm just looking to kick off a dialogue of the role that water changes play. Thanks!
 
It can be done and it's be done, tanks can be successfully kept without water changes. The parameters that you measure are stable, but you have to dose (as you do) some vital trace elements that you don't measure and are consumed by different organisms in your system.
I can be a harder approach to successful reef keeping and also depends on what corals you keep. WC are the simpler method to remove and replenish than dosing and the use of other nutrient export means. Also, some corals (specially SPS) become very difficult to keep without water changes.

On a system that small IMO the best approach is 20% water changes once a month, but nothing or nobody is pressing you to go this route. If you understand and measure what you dose and use the appropriate nutrient export methods you can successfully keep your tank with less or zero water changes.

Good luck.
 
I do believe in maintenance. In the years I've been keeping SW tanks, there were times when months went by without WC due to my schedule. I think as a tank matures and parms are stable, you could get away with less. My current reef is almost 4 yrs old, I started off with bi-weekly 15% water changes....I'm now at 15% WC every 6-8 weeks, and as you can see from my tank pics, there isn't any more room in it for corals to grow. Please be clear, I'm not saying WCs are NOT needed. I agree with the previous post. It also depends on the type of corals you're trying to keep
 
I think water changes are important, but not so much for nutrient export. You have to take into account all the things going into, and being consumed by, our tanks that we don't/can't measure. There are impurities in all the chemicals we dose and foods we add. These build up over time and could potentially be harmful. No matter how hard we try we cannot attain perfection in a closed system. There are too many variables. Water changes help remedy this.
 
Why should I do water changes? Because I don't have any intention to test for all of elements found in saltwater even if I could. Granted many of these may not change (decrease or build up), and even if they did, most of the usual creatures we keep may not care, but as smart as we may think we are, we aren't. I'm not even referring to waste build up. For the most part we think we can deal with waste by exporting or consumption.

just as an example:

I have some sensitive corals that will start to look less then 100%, I''ll test water and find nothing out of the ordinary (and I have a large stock of test kits).Then I'll do a small water change, even just a 5-10%, and the coral will perk up, and I'm asking myself okay what is it you liked about that?

Composition of seawater:
how many do we test for?
how many are critical (up or down) for a healthy environment for all the things we would like to keep?

Hydrogen H2O
Oxygen H2O
Sodium NaCl
Chlorine NaCl
Magnesium Mg
Sulfur S
Potassium K
Calcium Ca
Bromine Br
Molybdenum Mo
Ruthenium Ru
Rhodium Rh
Palladium Pd
Argentum (silver) Ag
Cadmium Cd
Indium In
Stannum (tin) Sn
Antimony Sb
Helium He
Lithium Li
Beryllium Be
Boron B
Carbon C
Nitrogen ion
Fluorine F
Neon Ne
Aluminium Al
Silicon Si
Phosphorus P
Argon Ar
Scandium Sc
Titanium Ti
Vanadium V
Chromium Cr
Manganese Mn
Ferrum (Iron) Fe
Cobalt Co
Nickel Ni
Tellurium Te
Iodine I
Xenon Xe
Cesium Cs
Barium Ba
Lanthanum La
Cerium Ce
Praesodymium Pr
Neodymium Nd
Samarium Sm
Europium Eu
Gadolinium Gd
Terbium Tb
Dysprosium Dy
Holmium Ho
Erbium Er
Thulium Tm
Ytterbium Yb
Lutetium Lu
Hafnium Hf
Copper Cu
Zinc Zn
Gallium Ga
Germanium Ge
Arsenic As
Selenium Se
Krypton Kr
Rubidium Rb
Strontium Sr
Yttrium Y
Zirconium Zr
Niobium Nb
Tantalum Ta
Tungsten W
Rhenium Re
Osmium Os
Iridium Ir
Platinum Pt
Aurum (gold) Au
Mercury Hg
Thallium Tl
Lead Pb
Bismuth Bi
Thorium Th
Uranium U
Plutonimu Pu
 
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I have also watched my corals perk up after a wc. There is a book I got years ago that I think originated in Germany called the Modern Coral Reef Aquarium (I think thats what its called). They were just dosing Kalkwasser for the top off and were calling for a wc of only a few gallons per YEAR. (I'm going by memory so this might not be completely accurate but its close). I know a mature well balanced system can go a long time without any wc's but I do them just to be on the safe side and for some reason I like doing them! I don't know why lol.
 
Very well put Pete !! If we tested everything we need to test for, the need for water changes would be so very evident. Even more so than now. In truth we could never acomplish a perfect enviroment even with that knowledge. Water changes are important. Look at your Corals. They will tell you just how impotant they are.
 
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I actually get lazy when it comes to WC. I change when I leave on vacations and when I am gone for a long period of time. Why? I dunno a piece of mind so I know it wasn't the person watching the tank's fault. I change my water... once every... 4 mo? The tank seems... the same before and after. I really feel that nature takes care of everything. Things adapt and overcome to everything. Just like humans do.
 
ive been in the hobby for over a decade, i have done tests of trial and error for many aquarium situations and of course this was 1 of nmy firsts tests. id say that it really depends on the system you have setup to see how often water changes are needed. if you have a fish only tank the odds of you getting away without water changes are less than that of the eco system of say a planted aquarium or reef tank. see in a planted tank or a reef tank you have created whats called an eco system, much like the self cleaning system that nature has set for itself. if you have provided enough live rock and flow in the tank and have certain creatures that will help to eat away at detritus build up in the substrate you wont have to change water as often but youll still need to add supplements that are absorbed by the life within the aquarium. i ran a 40 breeder reef tank this way for 2 years and everything was fine, i even had a pinnatus batfish living in there for close to a year until he died. but if you were to conduct your own experiment youll see that if you do frequent water changes instead of just replenishing the nutrients, that your corals will definitly look fuller and have a faster growth rate. especially if you use a high end salt that has excess nutrients, my personal favorite salt is tropic marin, but its a tad pricey for me, so i stick to the slightly cheaper salts and find they work just as well. when i buy salt i get either instant ocean reef crystals or seachem reef salt, which ever one is on sale that week lol. i see you have a 55 gallon, id reccomend doing a gravel vaccum biweekly pulling out about 20%-30% each time you do this, as for the skimmer clean as needed or at least once a week as this can be an area for parasites and bad bacterias to buildup, and the sponges clean biweekly, but not the same time you do you substrate cleaning/water change.....it should be gravel vaccum/water change wait 2 weeks, sponges cleaned, wait 2 weeks then the gravel vaccum/subsrate cleaning again etc etc. hope this helped -matt
 
I guess anything is possible.

Here's what I suggest. Stop doing water changes. If there's no need the way you're set up, the your tank will do fine. If there's a need, well, then I guess it won't do fine. ;)
 
I recommend doing small but regular changes. In my opinion and experience you can go without water changes for quite some time but it will eventually catch up with you and your tank might take a turn for the worse. I have a Litermeter now and do daily, automatic changes. It is not a big deal anymore and I think it will be great long-term. There are examples for successful no-water-change tanks, but how many contrary examples are there and is there a certain amount of luck involved?
 
Water changes are over rated and probably more of a shock on your system than just leaving it alone. I do little to no water changes, just top off out of the bathtub faucet, no dechlorinater. Only used sealab 28 blocks when coraline retreats. Only used half working Ramora skimmer. Never had a hair algae problem. Sometimes a little brown algae but who cares. Haven't used a test kit in over 5 years


03reef.jpg


01reef.jpg
 
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tang named junkyard said:
Water changes are over rated and probably more of a shock on your system than just leaving it alone. I do little to no water changes, just top off out of the bathtub faucet, no dechlorinater. Only used sealab 28 blocks when coraline retreats. Only used half working Ramora skimmer. Never had a hair algae problem. Sometimes a little brown algae but who cares. Haven't used a test kit in over 5 years


03reef.jpg


01reef.jpg
Click to expand...

Its a nice tank, but all or most of those corals in your tank being LPS's and mushrooms and leathers all like a slightly nutrient rich water than lets say ones that keep extremely brightly colored sps's. I bet you some of your nutrient levels, whether it be nitrate or phosphate etc etc are higher than those tanks, but that is not to say sps tanks are better or worse than softie tanks. (i'm not a reef-snob, I actually prefer mix reef myself)

All I'm saying is different strokes for different folks AND it depends on what type of tank you have. If you have a NPS tank with lots of hungry axoo dendros, sun corals, nps gorgonians etc, you better believe the waterchanging scheme for your tank will fail in that tank. It'll be overrun with nuisance algae, or the corals will die from lack of food. Conversely if you keep mostly softies and leathers in your tank, they are much more hardy and can thrive in slightly nutrient rich waters than brightly colored SPS corals. So yes, there are some tanks that REQUIRE water changes more frequently than others.
 
I used to do 50% water changes twice a week.

Now I do a waterchange of 10% twice a year. My tank is doing better then it was, which conincidently is why I tapred off on the water changes.

I use other means for nutrient export. I dose my tanks with several things and if the lack of helium or argon in the tank is disrupting my corals,they haven't told me so just yet. When they do, I will buy them one of those nice balloons. Maybe a Nemo one and let them talk funny. Joking of course.

:D
 
I think my main point in not doing water changes was partly out of lack of logistical resources, and lack of time. I only have 5g buckets, so mixing up a batch of 2-4 buckets worth of SW and making sure they all match salinity and temp is somewhat of a pain"¦which makes me avoid doing it.

I also haven't dived into SPS corals yet. I had a few softies, but after my tank temp climbed to 96F (when a heater shorted while I was on vacation), it cooked everything but my fish. So it's hard to say how well the corals are tolerating the water change schedule "“ seeing as I'm currently coral-less. So as of now I'll probably attempt a few SPS next time I go to the LFS.
 
CRC88 said:
I think my main point in not doing water changes was partly out of lack of logistical resources, and lack of time. I only have 5g buckets, so mixing up a batch of 2-4 buckets worth of SW and making sure they all match salinity and temp is somewhat of a pain"¦which makes me avoid doing it.

I also haven't dived into SPS corals yet. I had a few softies, but after my tank temp climbed to 96F (when a heater shorted while I was on vacation), it cooked everything but my fish. So it's hard to say how well the corals are tolerating the water change schedule "“ seeing as I'm currently coral-less. So as of now I'll probably attempt a few SPS next time I go to the LFS.
Click to expand...


I'll mix up 25-35g in a 42g brute, but only change 5g (5%) at a time to avoid shock due to pH, temp, Ca or what ever. I'll usually wait 2 -3 hours between 5g changes and at most I'll only do 3 in a day. So my water change routine is spread out over a couple days every other week, usually in the evening on commercial breaks etc

If I was running a fish only or even a softie tank I'd do less (maybe not even 10% every other month) as others have suggested. Keeping a mixed tank with softies, sps, lps and NPS (gorgs & sponges), I'm feeding at least 3 times a day and even though my trates are in check, in order to keep a couple of the gorgs happy and sps colorful, I just got in the habit of doing ~15-20% every 2nd or 3rd week. Right now, it's working for me, eventually I may be able to cut back some but I don't think I could get the results I have now with doing water changes only a couple times a year. By the way this is probably my 12 or 13th saltwater tank dating back to the mid seventies and water changes have been a thing of debate at least as long as I have been in the hobby
 
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