Doing super frequent water changes.. what can go wrong?
 

I want to try an experiment and was wondering about a couple of things. What i want to do is try to achieve an ULNS by doing very frequent water changes. Like, i'm talking 10% every 2 to 3 days. I have a 150g system so that's 15g every 2 to 3 days. What I'm wondering is what will be the fallout? I suspect the natural fauna of the tank could be diminished, but enough to be a problem? Has anyone ever tried this? Searching through the forums it seems the average minimum is about a week for a water change. My logic is that the natural ocean works well because it is highly diluted. Well, I figure if I inject new saltwater very frequently then I could nearly achieve this. So what's wrong with this logic?

hmm, interesting thought. Well I cant see anything bad about it, concidering when you have a najor nitrate issue, you ussally want to do frequent water changes. And all your doing when doing water changes is taking out old water and adding fresh new water with replenished elements in it. Now i suppose the reason why most people stick to weekly water changes is because its cheaper, yet still making sure that the tank stays healthy at the same time.

I would say try it out, and tell us of the outcome.

Ulns?

Ultra Low Nutrient System

Water Changing
 

I maintained a similar routine with a tank a few years back...

Every 3rd day i changed out 10% for over 6 months. I never did notice much of a difference. The nutrient levels did seem to reduce initialy, but i found that the skimmer would hardly produce any skimate. I suspect this was down to the dilution of waste although the skimmers weren't the best back then. Believe it or not, I did notice the nutrient levels actually increase over the long run! I put that down to the fact that i was using tap water :redface: and not R/O....:neutral: I think i was putting much more of the bad stuff back in :biggrin:

Ended up being a Chore.:sad:

Would be interested to know how you get on.....

Simon..

The biggest fallout is the cost of salt.

It's actually not that new of an idea. I'll have to check back some old threads but there are several articles are written about the idea of water changes and how basically there is a point of diminishing returns with them, and basically, not unlike feeding, "smaller more often" is better than "larger less often". Some systems in fact incorporate constant water changes - ie, there is always a steady stream or drip coming in and it just overflows into the drain. Some captive breeding systems are setup this way. You would have to measure your salinity though regularly and manually compensate for the drift.

To be honest though I'm not real sure you'd get a "true" ULNS out of increased water changes. Your rate of export has to match or exceed your rate of production and since one is steady state and one is stepped, I don't think you will truly get there. I think the tank will certainly benefit, but it's not an as aggressive method of nutrient removal as the bacterial based ULNS's.

I think it really comes down to time, energy and cost. Otherwise it's pretty much just win.

hmm maybe no need for a skimmer anymore mith that many water changes

I did think about the cost and reasoned that the amount of salt that I would need would probably be near what larger systems, say, 280g and up would use on a regular basis anyway? Plus, if this did produce an ULNS then that would eliminate the need for additives, but it sounds like this wouldn't be the case :sad:

.. thinking out loud here.. I wonder what would happen if you did frequent enough water changes to the point where the water in the tank was (nearly) constantly equal to fresh saltwater. Like say 90% fresh saltwater all the time?

well your corals would grow nice and fast and the fish would be healthy thats for sure.

We might be getting into two separate topics though here: reefbuilding and nutrient management. Dosing is really more about managing parameters that are directly responsible for coral growth; nutrient export helps growth in that nutrient buildup will inhibit growth so removing nutrients (and by extension, ULNS) will remove those inhibiting factors. But even a zero nutrient system won't grow corals if there is no calcium or alkalinity or magnesium to begin with.

So. Water changes does benefit both goals by removing the baddies and replacing the goodies that get used up. Certainly there are tanks out there that use only water changes as the primary tool and these are nice setups. And indeed, do enough water changes and you might not really need a skimmer.

But what I think you'll find is that with water changes alone, you will only be able to go so far with it. In a low demand system, it may be enough forever. But in a high demand system (such as one with SPS), the draw on the calcium and alkalinity is not linear over time. Ie., as your corals grow bigger, so too does their apetites for calcium, and thus you have to add more Ca and Alk to compensate. At a point you will find, I think anyhow, that water changes alone won't cut it, and you have to manually replace Ca and Alk anyhow (either by dosing or by calcium reactor). The main thing about this is that the Ca and Alk is now decoupled from the nutrient export - which ultimately is a good thing because the rate of Ca and Alk usage likely isn't directly proportional to the nutrient buildup (which is going to depend on the fish load, and how much/how often you feed, etc.)

So, I'm not saying I think it's a "bad" idea, but I think it's just not the most efficient or cost-effective method out there.

This is the article I was thinking of, BTW:
http://reefkeeping.com/issues/2005-10/rhf/index.php

A quick glance at it now though tells me I might have given the wrong synopsis for the article. So ..um .. disregard anything I said about "less is more" until you've read the whole thing for yourself and come to the same conclusion and if you come to a different conclusion please let me know so I can stop misquoting it. :lol:

I would be nervous about losing your beneficial bacteria causing a mini cycle. I've seen a tank crash from 3 times 60% water changes and each one was done daily. 4 th day before h2o change ammonia reading was 3. This person wanted to bring down his nitrates from 20 to 5. He saved his tank by doing 10% daily water changes for a week. Subsequently after that week his nitrates were 7.

Kevin

Generally agree with Tony's thought on p1.

The cost of the salt would outweigh the likely benefits. Perhaps consider less fish or feeding them only 2x's a week. Afterall, you don't need to remove what you do not put in. Maybe go with less water changes and less feeding for a while and see how it goes, was my approach back in 2006/2007.

I have done this, and I haven't noticed much of a difference until you get up closer towards 25% twice a week. I think you're better off achieving ULNS with Zeo or even vodka dosing. Cheaper in the long I'm betting.

While doing larger water changes less often is more efficient in lowering nutrients than smaller ones more often, stability is better with the smaller more often approach. This is why many people find better results with weekly changes over monthly ones. The question is, is there a line where too often becomes a problem? Is weekly really the most often you can go for best results? I don't personally think so, for a reef system I would promote more often as better, you'll just have to change a little more water each time to match the effectiveness of weekly or monthly changes.

I've setup a few systems including my own which use a similar principal but for different reasons. For automation or semi-automation smaller daily changes creates a simpler system and requires less water storage. Using this method I've always seen good results as stability is increased. Salt is either added manually or the top off water is has enough salt content to match the system requirements to maintain constant salinity. Using this method I've never noticed much change in skimming. I've also noticed my skimmer will stop working properly for about an hour after a standard 10% water change, so I don't see any real potential for a skimming problem.

As a final note I'll mention that public aquariums change water in their systems on a daily basis, I suspect they do this for two main reasons, 1 maintain low nutrients and good water quality and 2 maintain stability in reason 1.

Perhaps the loss in efficiency is outweighed by the gain in stability and simplicity. It makes much more sense to me to distribute a large water change into smaller ones, how often depends on how much water needs to be changed.

Running a basic zeo system on a 100gallon tank runs for about $60/month, depending on your salt brand, that same amount of money would pay for around 100 gallons of water each month. That's 10 10% water changes or roughly 2.5 10% changes per week. Sounds about the same until you consider zeo tanks require weekly 10% water changes, then it's obvious zeo tanks cost more.

While I agree with this logic I don't think it directly applies here. While larger water changes are definitely more effective in lowering nutrients, I don't believe the same is true for maintaining nutrients at a certain level. This is something I made up a while back to aid in explaining effects of water changes and also why so many people have nutrient problems.

The example is simple and as follows. A system containing 100ppm or nutrients at week one. The system on average adds 5ppm of nutrients each month or 1.25ppm each week. The chart shows how the nutrients decrease when comparing 25% monthly changes to 6.25% weekly changes (same amount of water assuming 4 weeks per month).

http://i11.photobucket.com/albums/a1...terchanges.jpg

It's obvious that monthly changes decrease the level sooner but once it reaches a critical level it remains constant and both monthly and weekly changes become equal. Also notice that the nutrients will never return to zero (why many people always fight nitrate levels) and that the weekly changes produce a more stable level.

So for maintaining low nutrients smaller more often changes may be better while for lowering nutrients larger changes less often are more effective.

I'll also say that while the obvious solution is to cut off the source as already stated this still has limits. Experts and authors will insist that fish require several feedings daily, this of course is not piratical for most reef keepers and we develop different approaches. I for one feed once daily and skip a day once in a while. However feeding less can result in some fish not being able to compete and starving to death. Feeding even less can result in all fish not being able to keep the required nutrients which can eventually cause death as well. One could cut the source even further back and decrease the amount of fish but with this logic why not remove the tank all together and eliminate the problem completely? While this may seem harsh I think if someone is willing to spend more on water changes to keep a couple more fish or feed a little more, that's his or her option.

Steve, I completely agree that "smaller, more often" produces a more stable system, and this is better; but doesn't a reactor or dosing routine offer higher control of the parameters? ... Hmmm, I guess if you're not as concerned with where they are, just that they are "good enough" then I guess it doesn't matter as much. The only thing is, you need to make sure your incoming water has good parameters and it's a rare salt that offers consistency in numbers year after year: you'll end up dosing into your makeup water anyhow, and at that point does it really matter if you dose your incoming water or your tank?

Just to be clear are you talking about levels of elements such as alk and Ca? And by reactor are talking about a Ca reactor as an example? My previous discussion was based on the assumption that these levels are out of the scope of this particular discussion as it seems to be more based on removing unwanted nutrients from the system, not replenishing elements. However I don't think the idea behind more frequent water changes is to eliminate the need for dosing or using such reactors, these may still be needed just as if only monthly water changes were preformed. If this were the case I would still assume more stable levels all around using the smaller more often approach, dosing or whatever would be easier to tune for consistent and smaller changes that occur more often than compared to a single larger change which occurred less often like a monthly basis. Inconsistent salt will effect both methods equally and therefore I don't think it's a variable of great concern in this discussion.

Dosing or other means of replenishing elements also may not be required if significant water is replaced often, however that will depend on many things.

Another interesting theory to consider is: No matter how much water you change it's not enough to maintain ultra low nutrients. Something else, like a skimmer for example, is always needed.

Even if a tank starts at 0ppm nutrients, and only adds 0.5ppm a week and you change 25% of water weekly you'll still build up to a stable level of 2ppm. This may not seem like a lot but keep in mind it's just an example to show the theory. You will never maintain 0 nutrients with water changes alone.

http://i11.photobucket.com/albums/a1...aterchange.jpg

Sorry Steve, I missed that you were only talking of nutrients. Somewhere on the first page Kien mentioned in passing that (to paraphrase a bit because I'm too lazy to go find it and quote it) that it would be nice if this could also eliminate the need for additives. Which I took to mean the big 3 (Ca/Alk/Mg). I wasn't sure if you were addressing that, or the nutrient thing. So I guess I'm in total agreement with ya, you were just better with the graphs and math and stuff. :lol:

Thanks for all the input everyone. Some great information here!

To clarify, when I said I wanted to eliminate the use of additives I meant additive designed to reduce unwanted nutrients like Zeo,Fauna,Vodka,Gfo, carbon etc.. There is a lot of stuff out there And I was just wondering if there was a way to simplify nutrient export to achieve a near ULNS. That's when the frequent water change came to mind.

It sounds like some have tried this without it making much of a difference though. Yes, cost would be higher but then people with larger systems need to spend this type of coin on their "regular" water changes.

Aside from possibly nuking my beneficial bacteria it sounds like there isn't much that can go wrong here. As mentioned, I think stability is the key. Lots of small-medium water changes. I may try this out for a few months and see how it goes. I suspect in the end I will get sick and tired of all the water changes but I'm still curious to see the results.

I honestly don't see how the bacterial cultures would be adversely affected (at least in a significant sense). The amount of free floating bacteria is minimal compared to the amount bound to the substrate and rock. I've known people to do 100% water changes (and done some myself) without there being a cycle afterwards. I'm thinking in Kevin's example, the 3 60% water changes in quick succession maybe somehow shocked the system and there was a bacterial dieoff as a result. I'm not sure what happened there though so I guess I shouldn't speculate. But theoretically, smaller water changes more often should really in fact impact the bacterial cultures even less than the typical weekly/monthly changes.

So I think you're good to go.

If you're going to give this a shot I would recomend daily changes rather than every few days. It would be easy to automate as all you need a pump on a timer that pumps water to a drain (be careful to avoid a siphon) and an auto top off system which allows you to top off with salt water with a lower salinity that maintains constant salinity in the display. A very simple system requiring very little time to maintain.

I agree with Tony about the bacteria, this is actually part of a myth similar to how UV sterilizers can harm your bacteria population. The fact is all you need is already attached within rock and substrate.
http://reefkeeping.com/issues/2009-04/newbie/index.php

Kien,

If you look at this thread (and wow, what a thread!) you will see that he is doing continual water changes. Go to about mid-way down the page and start reading.

http://reefcentral.com/forums/showth...0#post14332010

Hope that gives you food for thought.

Keeping a lower fish load is the easiest way to achieve lower nutrients. That's pretty simple logic, although people really don't seem to link the two for some reason.

Personally, I despise battling nutrients so I keep a small fish load. I am not using any artificial filtration at all; no carbon, GFO, filter socks, skimmer - not even a sump. The only mechanical things in my tank are the Tunze Wavebox, a MaxiJet 1200, and a heater. You will find very little algae in my tank, and my phosphate and nitrate are undetectable using both Salifert and Elos kits. Oh, and I'm one lazy SOB...I have done two 15% water changes since I set the tank up in June. :o

I have been using Zeo lately (my phos and nitrate were already undetectable before starting Zeo), but really only for the last 6 weeks or so for most of it. I'm not using any of the Zeo biological additives (yet), and I'm not dosing a carbon source. This isn't the first low fish load tank I've had either! I figure there is a simple way and a not so simple way. I would rather my tank is simple than have a large aesthetically pleasing fish load.

So a person shouldn't trivialize lowering the fish load like that! :wink:

I do a daily water change at about 1% a day in less then 5 mins. I have a barrel down stairs that has new water in it and a drain on my sump. Its been running for 5 weeks and my Kh is up and the tank is starting to look good.
NH4 has dropped and I used to run Zeo, which worked great, but to much time for now. I might start usiing both together.
I don't think I would do a larger water change consistenly. It would probility take out the good to.

While one person may be happy with less or no fish another may not, that was the only point to the previous quote. There are other options besides feeding less and removing fish.

On another note a tank setup in June with low stock won't require much to keep nutrients down but over time they will build up following the "lazy SOB" approach.

Like I said, it's not the first low nutrient low fish load tank I've had Steve. You can make yourself a low maintenance tank...depends what you want more. The "lazy SOB" approach WILL work, you just have to plan around it - it's all about balance. ;)

A freshly set up tank may actually have quite high nutrients...depends what approach you take.

I think that's what this hobby boils down to.. picking your battles. Everyone has their own unique goals and with them challenges to overcome or to achieve in reaching those goals. As suggested, some people are perfectly happy with a salt water tank with a few fish and low maintenance, while some people NEED to have to have that cool fish, and that cool fish, and oh, that one too! Need to have those LPS corals too, and SPS' that are thriving as well! Somewhere in between having just an empty tank with saltwater in it and a tank full (possibly overstocked) with fish and corals, the hobbyist has had to decide where the line is drawn and which battles to fight. Do I keep all those cool fish and risk them fighting one another, eating my corals, nuking my tank, do I deal with the high nutrients, dose to keep nutrients low? stock less? more live rock, less live rock, deeper sand bed, skimmer, no skimmer, bigger tank, smaller tank, more flow less flow? :drinking:

For me personally I am trying to find a balance where I can keep all my cool fish and corals, while at a cost (time and monetary) in maintenance. The battle I have chosen to fight (today at least) is how to achieve this with all the various methods of nutrient exporting. Frequent water changes just happens to be one that I was curious about.

Well said.

Update: No more super frequent water changes. I was changing out %15 every couple of days, then every 3 days, then I was back to my regular weekly water changes :lol::lol: That just ended up being WAY too much work and wasted water for me..

Next up for me, vodka dosing :biggrin:

Wow, I totally didn't see that one coming. :p

I gave it the 'ol college try! :P You know, I was wondering the other day, for those people who live on the coast, have you thought about using ocean water for your water changes? Just get a bucket of ocean water, heat it up to tropical temps, dump it into your tank. What could go wrong?? :-)

Yeah that's why I recommended daily automated/semi-automated water changes. Makes very little sense to do water changes often if you're doing them manually, the whole point is based on automation.

Only problem is not everyone can flip a switch and have water magically poor out of the/a tank and flip another switch and have water magically poor back in. My tank sits on the main floor in the middle of the house so their is nothing near the tank that I can drain water to easily. Water station is in the basement. I do avoid buckets though, as my changes go something like this..

1. Premix salt in 25g garbage pale a few days prior.
2. Turn off return; water drains into the sump to a safe level.
3. Long hose runs from the basement (drain in the furnace/water room) to the tank/sump.
4. A utility water pump is hooked in and pumps water out of the sump into the basement drain.
5. Take the utility pump into the basement and stick one end into the new saltwater reservoir. Pump now pumps new saltwater from the basement into the sump.
6. Turn return pump back on.
7. clean up.

It isn't automated but I'm also not hauling buckets around. It is still a bit of work though to pull out that hose, the pump, lay down towels, roll the hose back up, wipe the floor, store hose. Then there's the whole issue of dosing the new saltwater mix to make sure everything is up to spec..

There are lots of ways to automate and it can be done in almost any situation. Many people run small 1/4" water lines to and from the tank to remote water stations somewhere else in the house. I've also run these kinds of lines in many houses with completely finished basements, electrical fish tape is a good tool for the job.
http://di1.shopping.com/images1/pi/f...ian+Electr.jpg

LOL, yeah I tried that. You have to get it really deep. With all the seagoing traffic around here theres lots of "extras" in the water, not to mention all the nutrients. At one point I was using pasteurized seawater filtered to 1 micron and it grew the most lush green hair algae ever! :wink:

The public aquariums do it.. :mrgreen: but yeah, the collection points are way out there.

Down in the L.A. area I noticed the LFS's were selling a product called "Catalina water." Same idea, just huge vats of it so you could buy 40 gallons at a time if you wanted. They take a boat out towards Catalina Island, suck up huge amounts of water, take it back to the LFS's for selling. I never really understood what the benefit was though, for the cost of salt compared to the cost of anything else for the hobby, it seems like a lot of work. (This was ten years ago though that I was down there, maybe they don't do it any longer.)

When I was reading up on Balling method (the "true" Balling method, not the 2-part/3-part automated dosing we tend to do in North America that we just call Balling), the added salts put into the aquarium cause the SG to rise and so water needs to be taken out of the tank and replaced with RO/DI to maintain a steady SG over time. All done with slow peristaltic pumps so it's a more or less steady state situation. Anyhow I sort of wonder how this compares to a "continuous water change" too.

Kien have you considered Zeo a go at all?

Yes, Zeo is on my list to tackle after Vodka :-D I don't know if you've noticed but I'm trying to find the easiest way out (or in, depending on how you look at it) for me. Yes yes,I know there is no "easy" answer. I'm just looking for something that is "easy" and cost effective for me (not for others or in general). I thought that the water changes would be easy enough.. NOT! For some maybe (who can just flip switches). Vodka seems easy enough as there's only one thing to dump into the tank. Although I have read some bad reports so I'm still on the fence. Then there's zeo which makes my head spin every time I venture over to the zeo site. I know it can be as simple or complex as you want to make it but I still need to learn what each of the additives do.

Now, I don't really have a nutrient problem, Phosphate and Nitrates aren't picked up by my test kits but I know they are there. I get a film algae on my glass every couple of days and 14 feet of glass is a lot to magfloat! I run chaeto in my 'fuge and rowaphos which is helping with that I suspect. I'm just looking for that added punch of nutrient export.

And yes, I know I have lots of fish and I probably over feed so there are those options (ie, less fish/less feeding, etc) but that's not what I'm after.