Weekly water changes?
- Thread starter schigara
- Start date
A smaller water change tends to be less stressful on most fish.
A smaller change tends to stir up less pollution from the substrate.
If you only clean part of your substrate with each change, timid fish can take refuge on the other end, so that they don't get chased all over your tank by the siphon.
A smaller water change is more forgiving: A 10% change with water that is warmer or colder is easier tolerated than a 25% change. Same with ph, chlorine, etc.
A smaller water change done more often keeps parameters more stable than a larger water change done less often.
Of course there are times when larger changes are better- when dealing with Old Tank Syndrome, high levels of toxins, etc.
And if you only have robust, tough fish, it probably doesn't matter that much.
I think there are situations for both strategies.
A smaller change tends to stir up less pollution from the substrate.
If you only clean part of your substrate with each change, timid fish can take refuge on the other end, so that they don't get chased all over your tank by the siphon.
A smaller water change is more forgiving: A 10% change with water that is warmer or colder is easier tolerated than a 25% change. Same with ph, chlorine, etc.
A smaller water change done more often keeps parameters more stable than a larger water change done less often.
Of course there are times when larger changes are better- when dealing with Old Tank Syndrome, high levels of toxins, etc.
And if you only have robust, tough fish, it probably doesn't matter that much.
I think there are situations for both strategies.
"A smaller water change tends to be less stressful on most fish." That is untrue if, as stated repeatedly in this thread, the makeup water and the tank water are similar.
"A smaller change tends to stir up less pollution from the substrate." Also untrue. If the substrate is polluted, it should be full-depth vacuumed to get rid of the pollutants.
"A smaller water change is more forgiving: A 10% change with water that is warmer or colder is easier tolerated than a 25% change. Same with ph, chlorine, etc." See the first comment above. It is not difficult to match water temp or remove chlorine. If water changes are done frequently at at larger scale, the other parameters will be more stable and therefore match well.
"A smaller water change done more often keeps parameters more stable than a larger water change done less often." How about a larger water change done more often will keep the water parameters more stable than either of the preceeding cases?
"Of course there are times when larger changes are better- when dealing with Old Tank Syndrome, high levels of toxins, etc." Exactly backwards. In OTS, small frequent changes (daily) are needed to avoid osmotic shock to the fish suffering from long-term adjustment to horrible water conditions. Large scale changes at the beginning will likely kill fish. Once the water is in better shape, the percentage shange may be increased. High levels of toxins from accidents do call for massive immediate changes.
"A smaller change tends to stir up less pollution from the substrate." Also untrue. If the substrate is polluted, it should be full-depth vacuumed to get rid of the pollutants.
"A smaller water change is more forgiving: A 10% change with water that is warmer or colder is easier tolerated than a 25% change. Same with ph, chlorine, etc." See the first comment above. It is not difficult to match water temp or remove chlorine. If water changes are done frequently at at larger scale, the other parameters will be more stable and therefore match well.
"A smaller water change done more often keeps parameters more stable than a larger water change done less often." How about a larger water change done more often will keep the water parameters more stable than either of the preceeding cases?
"Of course there are times when larger changes are better- when dealing with Old Tank Syndrome, high levels of toxins, etc." Exactly backwards. In OTS, small frequent changes (daily) are needed to avoid osmotic shock to the fish suffering from long-term adjustment to horrible water conditions. Large scale changes at the beginning will likely kill fish. Once the water is in better shape, the percentage shange may be increased. High levels of toxins from accidents do call for massive immediate changes.
Yeah, what RTR said. He beat me to it.
If the incoming water has the same parameters of the water coming out, you can do 100% water changes every minunte and have no problems.
If the incoming water has the same parameters of the water coming out, you can do 100% water changes every minunte and have no problems.
"That is untrue if, as stated repeatedly in this thread, the makeup water and the tank water are similar."
Not true. A 50% water change is more stressful on fish than a 10% water change, even if the water is identical. Common sense should tell you this.
"If the substrate is polluted, it should be full-depth vacuumed to get rid of the pollutants.'
You can't get rid of all the pollutants. Especially if you have any rocks, plants, or other decorations. Have you ever raised Mbuna? Do you sugest removing all the rocks each time you do a water change?
"It is not difficult to match water temp or remove chlorine."
Depends on tank size, available time, and the differences in the waters you are trying to match: Coverting 50 gallons of chlorinated water that is 8.5 ph and eighty-five degrees to 50 gallons of dechlorinated water that is 6.5 ph and seventy-five degrees is more difficult that doing the same thing to twenty-gallons of water. Especially if you have a life other than aquarium tweaking. Common sense should also tell you this.
"If water changes are done frequently at at larger scale, the other parameters will be more stable and therefore match well."
Yes. But then, as I pointed out, this may also be more stressful on timid, fragile fish. If you did a 100% water change three times a day, you would have extremely stable parameters, and extremely freaked-out fish. For as long as they stayed alive, anyhow.
"How about a larger water change done more often will keep the water parameters more stable than either of the preceeding cases?"
How about doing changing enough water to keep the parameters healthy, but not so much that you are wasting time, energy, and stressing fish?
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Not true. A 50% water change is more stressful on fish than a 10% water change, even if the water is identical. Common sense should tell you this.
"If the substrate is polluted, it should be full-depth vacuumed to get rid of the pollutants.'
You can't get rid of all the pollutants. Especially if you have any rocks, plants, or other decorations. Have you ever raised Mbuna? Do you sugest removing all the rocks each time you do a water change?
"It is not difficult to match water temp or remove chlorine."
Depends on tank size, available time, and the differences in the waters you are trying to match: Coverting 50 gallons of chlorinated water that is 8.5 ph and eighty-five degrees to 50 gallons of dechlorinated water that is 6.5 ph and seventy-five degrees is more difficult that doing the same thing to twenty-gallons of water. Especially if you have a life other than aquarium tweaking. Common sense should also tell you this.
"If water changes are done frequently at at larger scale, the other parameters will be more stable and therefore match well."
Yes. But then, as I pointed out, this may also be more stressful on timid, fragile fish. If you did a 100% water change three times a day, you would have extremely stable parameters, and extremely freaked-out fish. For as long as they stayed alive, anyhow.
"How about a larger water change done more often will keep the water parameters more stable than either of the preceeding cases?"
How about doing changing enough water to keep the parameters healthy, but not so much that you are wasting time, energy, and stressing fish?
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Ken, you brought up a good point. If you have a tank that hasn't been maintained the way it should have been and then you go in and do a big water change including gravel vac you can stress the fish to the point that they could end up dying.
I disagree. I use a python so it's just as easy to change any amount of water. I do 50% every week. The pH out my tap is around 7.4 and in my tank it is 6.6 with CO2. I refill the tank slowly, taking about 20 minutes. My fish love the water change.
But you must conceed the point that IF the incoming water is EXACTLY the same as outgoing water, there would be NO STRESS AT ALL to the fish other than what comes from sticking a vacuum in the tank.
If you are trying to match 2 vastly different water supplies, then I would agree that the time it took to get things equal would be greater than if they were the same.
Besides, we are not talking about the time it takes to properly conduct a water change, rather we are discussing the stresses on the fish.
Noone here, and I assume I can include you as well, would advocate introducing new water to the tank that is not similar to the outgoing water.
Noone here would advocate putting 7.8Ph 13Gh 20ppm NO3 65degree water into a tank that just had 7.2Ph 5Gh 0ppm NO3 78degree water in it.
Again I restate my point.....The key to water changes is matching ingoing and outgoing water parameters.
The only way a large water change, if done with the above in mind, could be overly stressfull is if you took so much water out at one time that the fish were actually exposed to the air or could not swim safely.
If I hooked up a drain on my tank and placed a hose with new water inside the tank and as old water drained from the tank an equal amount of new water returned, I could forego weekly water changes altogether so long as BOTH water supplies matched exactly. Depending on my rate of exchange, I could, in effect, change 100% of my tanks water supply every minute if chosen. No matter how much water I decided to exchange, the only stress to my fish would be equal to the size of the current I was creating. The faster the exchange, the faster the current.
If you are trying to match 2 vastly different water supplies, then I would agree that the time it took to get things equal would be greater than if they were the same.
Besides, we are not talking about the time it takes to properly conduct a water change, rather we are discussing the stresses on the fish.
Noone here, and I assume I can include you as well, would advocate introducing new water to the tank that is not similar to the outgoing water.
Noone here would advocate putting 7.8Ph 13Gh 20ppm NO3 65degree water into a tank that just had 7.2Ph 5Gh 0ppm NO3 78degree water in it.
Again I restate my point.....The key to water changes is matching ingoing and outgoing water parameters.
The only way a large water change, if done with the above in mind, could be overly stressfull is if you took so much water out at one time that the fish were actually exposed to the air or could not swim safely.
If I hooked up a drain on my tank and placed a hose with new water inside the tank and as old water drained from the tank an equal amount of new water returned, I could forego weekly water changes altogether so long as BOTH water supplies matched exactly. Depending on my rate of exchange, I could, in effect, change 100% of my tanks water supply every minute if chosen. No matter how much water I decided to exchange, the only stress to my fish would be equal to the size of the current I was creating. The faster the exchange, the faster the current.
