Do you consider a water change to be an effective type of aquarium filtration method?

[PeterEde]

I think filter by definition would mean removing something from the water. So by definition. A water change is not filtering anything. It's a replacement.

So a water change or replacement is a known effective way to replenish your aquarium.

If you have a stable systems with low nutrient and dosing trace where's the point in a WC?

That's my plan.

 

[PeterEde]

One my my challenges is keeping my nutrients up. The only reason I do my water changes is to replenish trace elements

Why not dose then instead?
I was relying on WC and found Alk/Calc bounced daily. That's not a stable system
I've since started dosing trace,Alk/Calc over 24 hours and levels are looking very stable.
Since a WC wont make any great impact on my No3 I'm no longer doing weekly changes.
I'm trying to manage No3 via a skimmer, fleece roller, refugium and minimise feeding.

 

[PeterEde]

Water changes could technically be considered to be "filtration". It does remove some unwanted nutrients and ions and dilute the remaining concentration. In that way, I suppose it it slows the build-up of nutrients and unwanted ions. However, an argument could be made about the efficiency of the activity if being used for filtration purposes. Additionally, export of nutrients i.e. N, P, and DOC seems to be easier to control buy other means than it was in the bad old days. Nutrient levels in my tank are very low. I even add some from time to time, so there is no need for additional export or dilution... but that said... I do water changes and will continue to do so until my corals tell me to quit. I don't know what they are responding to, but when I do a water change, the the corals' response is positive.

maybe it's like opening the front and back door of your home and just enjoy the clean air coming in and pushing out the stale?

 

[Sral]

Yea, I am quite certain about my math and my answer being an appropriate response to an incorrect assertion (his #2).

FWIW, you seem to be the one who didn’t understand the post of mine, but perhaps that was partly my fault for not directing you to his #2 comment to properly understand my response,

I believe we were talking past each other ^^

@pledosophy in his second post doesn't touch on the topic, except the reduction in salt, as far as I can see.

Alas, the discussion continued, but I would still maintain that you jumped to something too close to judging before understanding what he might have meant. About your post: personally, I think I perfectly understand the factual content of your answer about limiting the buildup of nutrients and pollutants with water changes, I simply think it doesn't contradict his assertion about maths ^^

As @firechild mentioned in his post: the equilibrium level with water changes is:
Equilibrium [ppm] ~ weekly_buildup [ppm/week] / water change [1/week]

That makes what he wrote:
Equilibrium ~ 5ppm = 0.5 [ppm/week] / 10 [%/week] = 0.5 ppm * 10

 

[monkeyCmonkeyDo]

Water changes for me are a last resort. Some tanks need em.
Mine currently doesn't.
If the water got bad enough ya I would change the water but as it is its fine for what I need it.
I voted no.
Filtration can be mechanical or biological but I don't see a water change being a good filter so to speak.
D

 

[mandtj]

I do a 10% every 2 or 3 weeks...but it's more a means of allowing 'hoovering' of the coral sand or as a means of replenishing the water used up when changing the rowaphos in the reactor and discharging the first few mucky litres into a bucket...and other sump maintenance...

 

[Randy Holmes-Farley]

I believe we were talking past each other ^^

@pledosophy in his second post doesn't touch on the topic, except the reduction in salt, as far as I can see.

Alas, the discussion continued, but I would still maintain that you jumped to something too close to judging before understanding what he might have meant. About your post: personally, I think I perfectly understand the factual content of your answer about limiting the buildup of nutrients and pollutants with water changes, I simply think it doesn't contradict his assertion about maths ^^

As @firechild mentioned in his post: the equilibrium level with water changes is:
Equilibrium [ppm] ~ weekly_buildup [ppm/week] / water change [1/week]

That makes what he wrote:
Equilibrium ~ 5ppm = 0.5 [ppm/week] / 10 [%/week] = 0.5 ppm * 10

There’s no reason to debate who misunderstood who, but I stand by my post as a perfectly appropriate and correct response to the claim that

“2. You can also not remove pollution long term using water changes.”

IMO, that is a mathematically incorrect statement as written, and that is the only aspect of his post that I addressed.

 

[Sral]

There’s no reason to debate who misunderstood who, but I stand by my post as a perfectly appropriate and correct response to the claim that

“2. You can also not remove pollution long term using water changes.”

IMO, that is a mathematically incorrect statement as written, and that is the only aspect of his post that I addressed.

Well, if we want to learn something from this I would argue that there is ample reason to debate this. I do however believe that we have both already learned. I personally stand by my post that both of you run by a different understanding of the words "removing pollution" but ultimately think the same.

Thank you for your clarification, I believe that was and is the core difference here

 

[In the sticks]

!

 

[The_Skrimp]

I definitely do. Even if I’m carbon dosing and dosing alk and calcium to maintaining all of my numbers, I still see a huge difference between doing water changes and doing no water changes. My coral perk up after a WC, grow faster and stay more colorful when I’m consistent about it. My best guess is that even if I don’t need to remove nitrates or phosphates and even if everything else is in line, a water change will get rid of toxins and replenish elements that I just don’t measure for.

 

[mtraylor]

If you have a stable systems with low nutrient and dosing trace where's the point in a WC?

That's my plan.

Personally I do not do water changes as a form of maintenance. I dose nutrients and use calc reactor for nutrients, and I use reactors, skimmer, and filter socks, uv, etc to filter water.

If I do 1 or 2 water changes in a year that's allot. Some years no water change. However that is not the question of the OP.

 

[Timfish]

Absoulutely! How else to get rid of the DOC that's not removed by skimmers, GAC or sponges?

 

[Seymo44]

My vote is ‘in general, no.’

Water changes are great for replenishing trace elements and diluting pollutants. However, unless you are performing extremely frequent or very large water changes it’s not a very effective form of filtration.

Skimmers, refugiums, fleece rollers, algae scrubbers, media reactors, etc. all have their place in a balanced filtration setup. Not all forms of filtration are required, and some reefers may only use one form and have success. I’ve been successfully using only a refugium on an SPS dominated nano tank for over a year.

Water changes are best used as a means to remove detritus, refresh elements, and to dilute phosphates/nitrates if needed.

 

[Richsoar]

We started talking about aquarium filtration yesterday and someone reminded me that I forgot to add water changes as a filter option. There have been quite a few "tests" done on the effectiveness of water changes as it pertains to the exporting of nutrients or filtering water. Let's discuss!

Do you consider a water change to be an effective type of aquarium filtration method? Why or why not?

image via @CoralReefer2110

I've read a few of the replies and my opinion runs more along the lines of "your diluting". I like many of the reefers out there don't have huge systems; tank wise or water source wise. I currently have 2 72gal and a 45 gal tank and I store my RODI water in 1-1.5 gal jugs. I do have 3 6gal glass and 2 5 gal plastic jugs, but nothing like the starting picture in this thread. I go through 3 - 5 gals a week just in top off, so I can't imagine doing 20% water changes every 2 -3 weeks, so I don't. Probably on the order of once in a blue moon. Lol
Obviously diluting helps but then how much hindrance does it cause due to significant changes in all of the other good parameters?

 

[Greybeard]

Seems to work pretty good for Monterey Bay Aquarium... they pump 2000 gallons of seawater from the bay into their tanks every minute.

Location, location, location

Let's be honest. Manual water changes are a pain in the rear. Most of us would do just about anything to keep from carrying buckets of water around.

But... it works. It's reasonably inexpensive, easy to understand, hard to mess up. Forgiving, if you do mess something up...

Auto water changes? I about wiped out my tank with that one. DOS pump AWC, inlet pump stopped, outlet didn't. ATO did what it's designed to do, filled the ever lowering water level with fresh. Salinity was 1.012 when I noticed the tank looked like hell.

'No Water Change' systems? I tried Triton, didn't work out for me. Certainly not cheaper than water changes! Less labor? Not from my point of view.

 

[WhiskyTango]

65.5% of reef2reefers don't know the definition of a filter.

 

[pledosophy]

Many of the organisms we keep intentionally secrete organics, many of which are released specifically to kill or otherwise deter competitors for space, food, etc.

Some of those are potentially accumulating in reef tanks, and we may have no effective way to remove them, aside from water changes. Organic binders such as GAC and Purigen only remove certain types of organic matter. Skimmers remove other types. There are other organics that will not be effectively removed by these processes.

I discuss organics, including toxins, here:

Organic Compounds in the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com

Please help me to understand. (I did read the article you posted, I love reading your stuff. I did have to google things to understand what they were.)

If the organisms we keep are intentionally secreting organics, and they will continue to do so, then how is the math on that organic removal not similar to using water changes to remove nitrate.

If anything wouldn't the organisms secrete greater amounts of organics as they grew larger?

When we do a water change of say 20% we would only remove 20 % of the secreted organics. The organisms would continue to produce more. The next water change would only remove 20% of the now higher number. So on and so forth. Eventually the secreted organics would rise to a level of toxicity. It might take longer then it would with the more commonly understood elements but wouldn't they eventually arrive at the same conclusion?

Also to clarify my stance on water changes as it seems to be misunderstood. I am not against them, but would not label a filter which needs several other filters, as effective. To many hobbyists read that all they have to do is change 10% of the water every week and their tank will be successful. I haven't found this to be the case. There is simply more to it.


Also, in personal experience I have kept systems for as long as 4 years in between water changes, only adding new water when water was removed fragging corals. My tank was full of corals, Monti's bigger then a basket ball, pagoda cup I could use as a lid to a bucket, all grown from the size of a quarter. IME I never ran in to a toxicity issue with DOMs (or POMs). Do you have any hypothesis on why certain systems can thrive without water changes for so long?

Thanks for taking the time to explain this to us.

 

[HomebroodExotics]

No water changes works for me. I don’t understand the concept of water changes honestly. Tell me exactly what is in my old tank water that you think is so dangerous and I may reconsider. So far there’s just an idea of a boogeyman that lives in the old water and I’m not convinced the boogeyman is a big deal if we don’t even know what it is and can’t figure it out.

From my observations I feel like water changes are a fix for other bad practices or if you want to base your fish keeping method upon water changes which is fine, then by all means have fun moving water and salt around in circles.

 

[MnFish1]

I think filter by definition would mean removing something from the water. So by definition. A water change is not filtering anything. It's a replacement.

So a water change or replacement is a known effective way to replenish your aquarium.

I would think that at least some - if not most - but IDK - people that do water changes also siphon their sand/rocks and remove detritus. At least I do. I don't want to debate your method - everyone can choose what they want to do - but - in reality - there are numerous compounds/minerals/elements that we do not measure - that are often found after doing an ICP/DOC test - and the solution to any elements that are 'elevated' for the most part involves water change so - IMHO - A water change is removing undesirable things from the water (potentially)

 

[MnFish1]

65.5% of reef2reefers don't know the definition of a filter.

I think the question is awkwardly worded. If you actually look up the definition of the word 'filter'. It is passing liquid/etc through a device to remove something. In that sense - adding bacteria is not a filter. IMHO - the question is asking 'Can water changes act as a filter by removing undesirable chemicals from the water'. The answer to that question again only my opinion is yes.