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

[Delphinus]

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.

[sphelps]

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

[Red Coral Aquariums]

Originally Posted by kien

.. 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?

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

[wickedfrags]

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.

[sphelps]

Originally Posted by wickedfrags.com

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.

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).



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.

[Delphinus]

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?

[sphelps]

Originally Posted by Delphinus

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.

[Myka]

Originally Posted by sphelps

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.

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.

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!

[steve fedyk]

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.

[sphelps]

Originally Posted by Myka

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.

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!

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.