when doing water changes.....

ledvetterkim

AC Members
Feb 8, 2007
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i plan on doing water changes once every 2 weeks once my tank is established. is 20% ok? and also, do you need to condition the water that you put back in the tank before it goes in the tank..... such as would you use prime before you add the 20% water that was taken out? thank you.
 
i add treatment to the water before i put it back into the tank.
to determine how much to take out and how often you need to, buy a test kit and monitor your perameters.when your nitrates start to get high, thats the time to change the water.
i believe 25% min. is reccomended but ive heard of people doing up to 75% partial water changes.
 
20-25% once a week is optimum but assuming you dont have a highly stocked tank, I'm sure you will be fine doing a 25% every 2 weeks. As for the water that you are replacing, make sure that it is the same temperature and that you add enough prime for the ENTIRE tank when adding the new water.

For example, when adding 25 gallons to a 100 gallon tank, you add prime as directed for 100 gallons, not 25.
 
water changes, done correctly, are only good for the tank. they won't hurt your fish or your filtration. make sure to always add dechlor when you fill the tank (before you turn your filters back on) and try to keep the temps within a few degrees of each other. a lot of people do 50% changes every week.

if you are replacing water with a bucket, then treat the amount of water in the bucket before it goes into the tank. if you are using a python, then add the dechlor before or while you are adding the new water, and treat the entire tank volume.

so, if you're using a 5g bucket, you add 1/2ml prime to the bucket, then put the water into the tank. repeat for every bucket.
if you use a python, and you have a 50g tank for example, then put in enough prime for 50g before you add new water through the hose.
if chlorinated water is kept separate from tank water, there is no need to use enough prime to treat the whole tank. if you read the instructions, it says what to do on the bottle, i believe.
 
ive heard of people doing up to 75% partial water changes.

75% in extreme cases (eg when disaster strikes and you need to clean it out fast, otherwise 75% will kill off too many bacteria and send your tank into another cycle).

Id say 25% is good. However if you can get in a water change weekly, that would be great. Otherwise once a fortnight should be ok for most fish (what are you intending on keeping?)

Yes, condition the water in the bucket (or whatever you plan to use) from the tap before you put it in. Not the water in the tank.
 
water changes do not kill off bacteria. the bacteria are attached to tank and filtration surfaces, they are not free-floating in the water. so no mini-cycle unless you take like 3 hours to do it and let the filters dry out. . . .
 
Yeah true.

However if you take out 75% of the water then you are just going to stress your fish as they will have to acclimatise again as the water has not been going round through the ammonia and bacteria and thus isnt established... Plus the PH can change and fish slime-coating can be lost.
 
75% in extreme cases (eg when disaster strikes and you need to clean it out fast, otherwise 75% will kill off too many bacteria and send your tank into another cycle).

Id say 25% is good. However if you can get in a water change weekly, that would be great. Otherwise once a fortnight should be ok for most fish (what are you intending on keeping?)

Yes, condition the water in the bucket (or whatever you plan to use) from the tap before you put it in. Not the water in the tank.
acctually, the python pumps water into the tank and then you add the dechlorinator in there. i have never heard any problems about people that add their dechlor to their tank and then add the water. if the dechlor could hurt the fish if you put it in the water before, then it can hurt them after too. not all of the dechlor is absorbed right away.


weekly water changes are best, especially for small tanks, even vital IMO. 25% a week is the minimum, and the best for the overall fish;s and tank in general's health.
 
Yeah true.

However if you take out 75% of the water then you are just going to stress your fish as they will have to acclimatise again as the water has not been going round through the ammonia and bacteria and thus isnt established... Plus the PH can change and fish slime-coating can be lost.

Yeees. . . but if you regularly do large 50-75% water changes then the tank water is always very close in composition to the tap water you are adding, so the fish will not be stressed. There IS a danger in leaving a tank and doing small changes for months and then suddenly deciding to do a huge WC. When the tank water starys too far from the tap water, then problems can crop up with Old Tank Syndrome.

Thoretically, if you only do 25% every 2 weeks, then it takes a 2 months for all the water to be replaced. if you do 50% once a week, the water gets turned over completely every two weeks.
 
i do weekly 50% wc's, but i had an overstocked tank that i did weekly 75%wc's with no probs. some discus breeders even do daily 100% wc's. i would suggest weekly 25-50% wc's for optimal water perams.
 
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