Are water changes necessary?

[steveoutlaw]

So I was doing a water change today and I started thinking (I know, I know, I shouldn't do that). Are water changes really necessary? If you are using liverock and livesand for biological filtration, using a skimmer to remove the fish doo-doo and using a refugium for nutrient export.......why would you need to change the water?

[dhoch]

Well, mineral replacement is one...(and I'm not just talking calcium, alk, mag... there are many other things in salt water that are not used up as quickly in our tanks)...

 

 

Plust with the added benefit of additonal reduction in wastes it's a good idea...

 

Now I knwo there are many people who do not, but I have been religously doing ~10-15 gal/week on my 180 ( plus ~another 30-40 in refugium/sump) and I've found things are very happy.

 

Dave

[emissary]

I used to be REALLY REALLY lazy about water changes (I still am once in a while) but I went through a period of 2 years where I did maybe 7 of them. Did anything die? No. But as soon as I did several water changes as a result of an algae outbreak I (a) solved the algae problem and (B) noticed a significant increased growth rate and coral "happiness." Are they necessary? If I understood how to keep all my trace elements in balance then perhaps not. They're a convenient ,easy, and safe way to keep all my levels where they should be though, imho.

[Gadgets]

I also give my tank (75g) a 15-20% water change every week, as well as siphon out any detritus. Everything is happy and I am seeing excellent growth from all of my SPS.

[flowerseller]

I believe exchanging water regularly is one of the best things you can do for your tank.

Pointed out already are trace element replenishment, but the real kicker is Nitrate reduction by

means of dilution.

[Jon Lazar]

I lump frequent water changes into the same category as good lighting, good filtration, and good water movement, and consider all of them "necessary."

 

Could I have a successful reef with crappy lighting? Probably; others have. But I think the long-term benefits of all of these factors, including water changes, makes them necessary.

 

Jon

[Guest clownfish4]

Refugiums can't remove all nutrients, and as Chip said, the key here is removing nitrates. In nature, plants are not responsible for 100% of nitrate reduction. Some is absorbed into the ground and some is diluted into the atmosphere as gas. In our tanks we can't replicate these processes and must make up for it with water changes. Although I can't say for sure, I believe if you never did a single water change, any tank would crash in time. Just a matter of how long, which would have many different factors.

[Guest seantadez]

you do water change every week? MG i do each two weeks... :cyclist:

[Gadgets]

you do water change every week? MG i do each two weeks... :cyclist:

 

Yup! I am finishing up one right now as I type. :D

 

Did a reading of parameters before the water change:

 

PH- 8.25

Sal- 1.025

Am- 0

NO2- 0

NO3- 0

PO4- 0

Cal- 460

Alk- 8dkh

Mg- Did Not Test

[Guest Ominojacu]

So I was doing a water change today and I started thinking (I know, I know, I shouldn't do that). Are water changes really necessary? If you are using liverock and livesand for biological filtration, using a skimmer to remove the fish doo-doo and using a refugium for nutrient export.......why would you need to change the water?

depends on your water conditions, to lower nitrates and ammonia, yes, but with a caveat, if you need to lower nitrates or ammonia, you should do weekly water changes at a minimum to be reasonably effective. For trace elements. basically useless, your better off supplimenting, see the following article for more information:

 

http://www.reefs.org/library/article/t_brightbill_wc.html

[londonloco]

Absolutley, 100% necessary, 20% weekly water changes on my reef, 50% weekly water changes on the other four tanks....well, maybe I skip a week on the reef, but never go 2 weeks. And I never skip on my freshwater (discus and puffers....).

[Guest Larry-T]

Doing regular water changes reduces harmful chemicals that your system can't reduce, as well as reducing, or doing away with, the need for a lot of the supplements that people use.

 

The entire supplement industry came into being based upon the "expense" of continually making up new salt water and making changes. In today's world, most of them are unnecessary if you do regular changes.

[Guest Ominojacu]

Doing regular water changes reduces harmful chemicals that your system can't reduce, as well as reducing, or doing away with, the need for a lot of the supplements that people use.

 

The entire supplement industry came into being based upon the "expense" of continually making up new salt water and making changes. In today's world, most of them are unnecessary if you do regular changes.

 

From the article mentioned above:

<An initial concentration of 600mg/L was chosen. In natural saltwater, magnesium is found at roughly three times the concentration of calcium. A target level of 1200mg/L has been selected. Using the graph in Figure 5, one can find how many weeks it takes to reach 1200mg/L using water changes, for any tank size. Using 25% or 50% changes, you will see that the graph begins to plateau as the magnesium level nears 1200mg/L. The same occurs as the levels approach 1200mg/L using 10% water changes. Yet with 25 weeks of performing a 10% change per week, the magnesium level is still not up to 1200mg/L. It would take 16 water changes at 10% water volume to reach even 1100mg/L. Using 25% changes, it would take 6 changes to reach 1100mg/L, and about 18 changes to finally reach 1200mg/L. Using 50% water changes - which by most accounts are stressful on reef tank inhabitants - would take 3 changes to clear 1100mg/L, and about 12 changes to reach 1200mg/L. Notice the large number of changes, for all 3 percentages shown here, required just to go from 1100mg/L to 1200mg/L. Notice also that water changes are by no means fast nor inexpensive when used to correct such ionic imbalances.>

 

I am not arguing that water changes are useless, but that the typical 20% every two weeks is, if you know you have a problem with nitrates or ammonia, you probably need to be doing 50% water changes weekly for several weeks, and as far the trace minerals supplimenting is quicker, why wait for 18 or so water changes to reach normal levels? Even in a balanced tank, less then 20% weekly seems like a useless task that will not effect your ammonia, nitrates levels and definitely not keep up on the mineral loss. I agree water changes are good, but if your not doing them weekly you might as well be skipping it altogether. 50% weekly sounds ideal.

[quazi]

50% a week! YIKES! I am luck to do 50% in six months. I just do not do much in the way of water changes. Not that I recommend it. However, my tank has done very well without them, and I do not have the time nor real inclination to perform a lot of water changes.

 

If my fish or corals were were unhappy, then I change water. If my tank is filling up with nasty stuff in the bottom of my sump or main tank, then I change water to syphon out the nasty stuff.

 

I dose calcium and kalk. That seems to produce happy critters in my tank.

 

Maybe I look at it like I look at fertilizing my lawn: If my lawn is fertilized, I have to mow it. If my tank is too happy, then my corals grow to fast and I have to frag them. My tank is out of control now, I would hate to have more growth with water changes

[Larry Grenier]

Brag, brag, brag...