Too many water changes? Is it possible?

[ShadowBass]

I don't think too many water changes are possible.

as long the water is of proper pH, temperature, and dechlorinated etc you won't cause you tank to cycle again.

lots of discus gurus change 50% of their water daily, and they don't have problems..

as long as its done properly, its fine.

we use to have tanks at the LFS where I used to work that got a 25% water change daily...

as long as you are not also going crazy on cleaning your filter every day etc. you won't cause a cycle..

if on the other hand you are changing the water everyday but ALSO rinse the filter every day too, well, then you can run into some major ammonia and nitrite..

I was just about to mention discus.

I've never ever had a problem doing large water changes.
Yes, if you let your tank go for weeks and weeks and then do a very large water change you may shock your fish because you've let nitrates and all kinds of other organic compounds build up, not to mention the PH is probably no longer the same as out of the tap, HOWEVER, if you are doing large water changes frequently the water in the tank should not be that disimilar to the water you are adding from the tap, assuming your tap water is not poorly buffered.

We are doing 50% water changes daily on our 55g with 16 baby dats, 5 baby clown loaches and a couple of baby BNs. I think this is a GOOD thing because as most of you know indos grow HUGE and clown loaches grow pretty big. Since these fish are still growing and will grow to sizes much much much larger than would be supported by a 55g tank water quality needs to be strictly monitored and maintained to make sure there is no risk of stunting or other health problems while the fish are growing. They all are being fed several times a day and heavy feeding will QUICKLY soil water, so it is imperative that water changes be done frequently.
Letting the tank water sit for a day and then changing 50% of the water consistently isn't necessarily going to cause a huge variation in water parameters.

Can it? Yes, DEPENDING on your tap water.
It can be dangerous to do large water changes if your tap water is poorly buffered or if it changes PH and other parameters sometimes. Not everyone's tap water is consistently the same every time.
If you're planning on doing large water changes (and really even if you're using tap water at all) you should be watching your tap water closely anyway. Make sure the water does not drop significantly in PH after it has sat overnight or even for a couple of days. Make sure the water you're taking out of the tap matches the water that you are putting into the tank.

If you want to go overkill and make sure that the water you are using to do WCs is exactly the same every time then either age the water in a large barrel or holding tank, or get an RO unit and mix the water yourself.

*shrug* There CAN be downsides to doing large water changes, but my point is there does not HAVE to be a downside to it. Large water changes in and of themselves are NOT a bad thing, clean water is GOOD for your fish. Fish that have very clean water show significantly better growth and health than fish in tanks that have small water changes and good/average water quality.

As a warning though: Some fish are very sensitive and may be extremely sensitive to chlorine. If you are worried about your fish age the water rather than adding dechlorinator directly to the tank and filling it from the tap. Some people prefer to age water no matter what, but this doesn't mean that your fish still can't benefit from large water changes often, it will just be a bit more work since you won't be able to fill directly from the tap.
When I was using garbage cans to age water for my tanks I pumped it out of the can with a powerhead into the tank. So then I still had the ability to do plenty of water changes without too much work.

I guess in short, adding tapwater directly to your tanks in large amounts and often CAN be bad if you don't watch the water parameters in both the tapwater and the aquarium. It can also be bad if you have chlorine sensitive fish.
Large water changes THEMSELVES are not bad at all because keeping your water nice and clean is not bad for your fish in any way whatsoever.

 

[ercnan]

Everyone's playing nice so far

 

[ercnan]

I was just about to mention discus.

I've never ever had a problem doing large water changes.
Yes, if you let your tank go for weeks and weeks and then do a very large water change you may shock your fish because you've let nitrates and all kinds of other organic compounds build up, not to mention the PH is probably no longer the same as out of the tap, HOWEVER, if you are doing large water changes frequently the water in the tank should not be that disimilar to the water you are adding from the tap, assuming your tap water is not poorly buffered.

We are doing 50% water changes daily on our 55g with 16 baby dats, 5 baby clown loaches and a couple of baby BNs. I think this is a GOOD thing because as most of you know indos grow HUGE and clown loaches grow pretty big. Since these fish are still growing and will grow to sizes much much much larger than would be supported by a 55g tank water quality needs to be strictly monitored and maintained to make sure there is no risk of stunting or other health problems while the fish are growing. They all are being fed several times a day and heavy feeding will QUICKLY soil water, so it is imperative that water changes be done frequently.
Letting the tank water sit for a day and then changing 50% of the water consistently isn't necessarily going to cause a huge variation in water parameters.

Can it? Yes, DEPENDING on your tap water.
It can be dangerous to do large water changes if your tap water is poorly buffered or if it changes PH and other parameters sometimes. Not everyone's tap water is consistently the same every time.
If you're planning on doing large water changes (and really even if you're using tap water at all) you should be watching your tap water closely anyway. Make sure the water does not drop significantly in PH after it has sat overnight or even for a couple of days. Make sure the water you're taking out of the tap matches the water that you are putting into the tank.

If you want to go overkill and make sure that the water you are using to do WCs is exactly the same every time then either age the water in a large barrel or holding tank, or get an RO unit and mix the water yourself.

*shrug* There CAN be downsides to doing large water changes, but my point is there does not HAVE to be a downside to it. Large water changes in and of themselves are NOT a bad thing, clean water is GOOD for your fish. Fish that have very clean water show significantly better growth and health than fish in tanks that have small water changes and good/average water quality.

As a warning though: Some fish are very sensitive and may be extremely sensitive to chlorine. If you are worried about your fish age the water rather than adding dechlorinator directly to the tank and filling it from the tap. Some people prefer to age water no matter what, but this doesn't mean that your fish still can't benefit from large water changes often, it will just be a bit more work since you won't be able to fill directly from the tap.
When I was using garbage cans to age water for my tanks I pumped it out of the can with a powerhead into the tank. So then I still had the ability to do plenty of water changes without too much work.

I guess in short, adding tapwater directly to your tanks in large amounts and often CAN be bad if you don't watch the water parameters in both the tapwater and the aquarium. It can also be bad if you have chlorine sensitive fish.
Large water changes THEMSELVES are not bad at all because keeping your water nice and clean is not bad for your fish in any way whatsoever.

Well said.

 

[aropal]

HOWEVER, if you are doing large water changes frequently the water in the tank should not be that disimilar to the water you are adding from the tap, assuming your tap water is not poorly buffered.

Well that's the key issue isn't it. People usually change water out of necessity and if they are doing large percentage bulk water changes then that is probably because they have waited a longer than optimal period between water changes.

The question is how long an interval would be necessary for sufficient dissimilarity to be created between tank and tap water to cause stress to a given species of fish. Until someone can provide a metric I'd suggest the best policy is to remain cautious and make water changes smaller and more often.

 

[Nova 8]

Both side have their advantages;
Big water changes will weaken your biological filtration by starving them and if you have to go away you either have to build them back up before you go away or suffer a small mini cycle which no matter how you put it wont be good for the fish. But on the other hand you have lots of clean water going in every day and you fish will grow quickly due to this. Also if there is a power failure your tank is already had a large water change and if you have to do another one your fish wont get shocked.
Little water changes promote good, strong biological filtration, meaning if anything happens to you in your day to day life you don't have to stress about your fish. But, then if something does happen, like a power failure, your fish are at more risk cause the tank relies on the filtration more. If you have to do a water change and if it has to be big due to an ammonia spike since the filter isn't on your fish are more likely to shock from it.

Each side has its pros and cons, its up to the individual to which way they choose. Me I do both, I do big water changes when I get the chance but if I know that in the next couple of weeks I'll have to work more I'll slow decrease the amount and number of water changes and increase the Bacteria in the filter.

 

[ShadowBass]

Well that's the key issue isn't it. People usually change water out of necessity and if they are doing large percentage bulk water changes then that is probably because they have waited a longer than optimal period between water changes.

The question is how long an interval would be necessary for sufficient dissimilarity to be created between tank and tap water to cause stress to a given species of fish. Until someone can provide a metric I'd suggest the best policy is to remain cautious and make water changes smaller and more often.

It all depends on your type of fishkeeping. Those who heavily overstock need to do larger water changes more often or else the buildup of nitrates and other organics may effect the health of the fish.
Those who keep normal or light stocking levels don't have to worry as much about nitrate buildup and probably are better off with smaller water changes more often to guarantee stability in the tank.
I'm in no way saying that large water changes are necessary for all hobbyists, just that large water changes on a consistent basis will not necessarily be detrimental to the health of the fish, although that seemed to be implied somewhat.
I have honestly never seen a noticeable cycle on a tank when I suddenly did not have the option of doing daily water changes, though this is theoretically possible. I'm sure there was some kind of spike in ammonia but not enough to even register on a test kit, so not as worrysome as some would imply.
Some fish that may be extremely sensitive to ammonia or nitrites may be effected, but for the most part experienced fishkeepers aren't going to be keeping those kind of fish in a heavily stocked situation. If you have very sensitive fish they should be kept in a lightly stocked tank where stability can be guaranteed.

Like I said, it all depends on the indivual, the type of fish, the stocking level, and several other factors. Some of my tanks that are lightly stocked get smaller water changes less often. My riverfish tank, which has extremely hardy native fish gets larger water changes less often because honestly it would be about impossible to shock those fish enough to effect them negatively. I also like a large amount of bacteria on that tank since it is lower priority and won't get water changes as consistently as the other tanks. Those fish are all happy and healthy and the water parameters are just fine even with the least maintanence.
Know what fish you are keeping, their sensitivities (or lack thereof), and your stocking levels then choose a maintanence schedule based on that.
I don't think any one level of maintanence is correct for everyone, so hopefully I did not imply that in my first post.

 

[cykotik]

wow! i learn so much from MFK! i want to thank everyone for their input and for giving me more knowlegde on how to successfully keep monster fish.