I have 70 ltr tank and i just want to know how often i need to change water. I have two pumps running and i hsve 6 cardinal 4 red phantom 5 rumny nose 3 harliquin 3 panda cory 2 zebra 2 platty. So far i have been advised every day every other day and once a week. Obviously I want to do whats best for the fish
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How often water change 70ltr tank?
- Thread starter kevfiz
- Start date
I pretty much agree with Nick; 50%, done once a week, is a good baseline to aim for and is a suitable amount for most set ups, once they're cycled.
Your tank is quite heavily stocked though; what level are your nitrates in the tank compared to your tap water?
Nitrates are not the only reason we do water changes, but they way they build up in your tank gives a fairly reliable snapshot of whether your water changes are adequate or not.
Your tank is quite heavily stocked though; what level are your nitrates in the tank compared to your tap water?
Nitrates are not the only reason we do water changes, but they way they build up in your tank gives a fairly reliable snapshot of whether your water changes are adequate or not.
I'm afraid 'spot on' isn't accurate enough to give us any useful information.
Can you post the actual numbers, please?
Can you post the actual numbers, please?
mikey11
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there are no set cut and dry guidlines when it comes to water changes, too many different variables come into play, type of food, how much food, filtration, fish stocking, types of fish, how you maintain the tank, etc etc,
having said that, from the tank you describe, IMO every other day is way overkill, i would change 25-50% once a week, that is assuming the tank is otherwise well taken care of and maintained properly
having said that, from the tank you describe, IMO every other day is way overkill, i would change 25-50% once a week, that is assuming the tank is otherwise well taken care of and maintained properly
There are two things to keep in mind with this issue. First, a balanced aquarium and second an aquarium that is not really in balance but pushing the envelope, so to speak--which is the case here.
When an aquarium is biologically in balance, it means the number of fish (taking into account their size and the species and number within each shoaling species) is in balance with both the physical space they have plus the water volume they are in. The tank décor factors into this as well. Fish that are in an environment that does not address their requirements (water parameters, numbers, aquascape, etc) will have more impact on the biological system than would be the case if their requirements are all being met. The more water you change, provided the parameters of tank water and tap water are reasonably similar, the better for the fish, always. You really cannot change too much water. Nor can you wait until test results show a problem--by then, the fish are already being negatively affected.
Fish in nature live in the same water for a few seconds, pretty much the time it takes for one mouthful of water to pass through their gills; the next mouthful will be "fresh" water because of the fish to volume ratio, flowing water, etc. We cannot hope to come even close to this in a home aquarium. So we do regular partial water changes to compensate as best we can. Provided the tank is not overstocked, and the fish are not overfed, and the requirements for the species have all been met reasonably well, this works. But as soon as any of these factors is out, trouble begins and water changes may have to be increased in volume or frequency or both, until the problems are addressed and the balance restored.
So, assuming the balance is basically present, a regular partial water change once a week of around half the tank volume will mean healthier fish.
Filtration was mentioned, but this only goes so far; even in the best filtered aquarium there can still be an imbalance. Water changes do much more than any filter can ever accomplish, and there is no substitute for water changes.
Taking the present aquarium in post #1, there is not a balance so changing more water is advisable until this can be resolved. A 70 liter (> 20 gallon) tank is not sufficient space for all of the fish named. I'll explain.
Some of these fish are shoaling, meaning they "expect" to be in a group, and this absolutely must be provided or the fish will have stress at minimum, and this may lead to other problems. Stress weakens the immune system, and further weakens other processes that keep the fish healthy and functioning properly. I cannot get into that involved issue now, so I'll move on. The species of tetra, rasbora (harlequin), danio (zebra) and cory are all shoaling fish, and most of these should have at least six of their species. Rummys should have more. There is no space for all of these, so that means the tank is now overstocked. Sorting this out is another whole topic, but I do advise it.
Byron.
When an aquarium is biologically in balance, it means the number of fish (taking into account their size and the species and number within each shoaling species) is in balance with both the physical space they have plus the water volume they are in. The tank décor factors into this as well. Fish that are in an environment that does not address their requirements (water parameters, numbers, aquascape, etc) will have more impact on the biological system than would be the case if their requirements are all being met. The more water you change, provided the parameters of tank water and tap water are reasonably similar, the better for the fish, always. You really cannot change too much water. Nor can you wait until test results show a problem--by then, the fish are already being negatively affected.
Fish in nature live in the same water for a few seconds, pretty much the time it takes for one mouthful of water to pass through their gills; the next mouthful will be "fresh" water because of the fish to volume ratio, flowing water, etc. We cannot hope to come even close to this in a home aquarium. So we do regular partial water changes to compensate as best we can. Provided the tank is not overstocked, and the fish are not overfed, and the requirements for the species have all been met reasonably well, this works. But as soon as any of these factors is out, trouble begins and water changes may have to be increased in volume or frequency or both, until the problems are addressed and the balance restored.
So, assuming the balance is basically present, a regular partial water change once a week of around half the tank volume will mean healthier fish.
Filtration was mentioned, but this only goes so far; even in the best filtered aquarium there can still be an imbalance. Water changes do much more than any filter can ever accomplish, and there is no substitute for water changes.
Taking the present aquarium in post #1, there is not a balance so changing more water is advisable until this can be resolved. A 70 liter (> 20 gallon) tank is not sufficient space for all of the fish named. I'll explain.
Some of these fish are shoaling, meaning they "expect" to be in a group, and this absolutely must be provided or the fish will have stress at minimum, and this may lead to other problems. Stress weakens the immune system, and further weakens other processes that keep the fish healthy and functioning properly. I cannot get into that involved issue now, so I'll move on. The species of tetra, rasbora (harlequin), danio (zebra) and cory are all shoaling fish, and most of these should have at least six of their species. Rummys should have more. There is no space for all of these, so that means the tank is now overstocked. Sorting this out is another whole topic, but I do advise it.
Byron.
AbbeysDad
Fish Gatherer
What's best for the fish is to rehome some of them as you are currently overstocked. You 'could' do a 50% water change 2 or more times a week as a temporary solution to pollution, but this gets old quick and folks tend to back slide and the stock suffers. Better to rehome some of the fish to get a more appropriate stock load - then a 25-50% weekly water change does the trick.
AND plants do help purify water as well as add a much more realistic environment for the fish and the viewer.
mikey11
Fish Crazy
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oddly enough, and ironically.....generally speaking, getting advice from a fish store is a poor idea, most of the people working there only know how to scoop and bag fish, and clean the tanks, and were probably flipping burgers, or selling car stereos last week
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