Which water change schedule?

[LogJam]

Hello All:

This question may be one of those where there is more than 1 correct answer. I was trying to determine how often to perform a water change.


My LFS says 30% once per month.

One book says 15% weekly.

Another book says 5% per day.


I have no problem performing water changes. I do have a problem with determining when! Per day would not work for me.

What sorts of schedules do you guys use?

Thanks!
LogJam

 

[AikidoGuy]

Myself and many other seasonsed hobbyist do 50% water changes everyweek on every tank. I do my gravel cleaning with a python everyweek. While gravel cleaning I remove about 50% of the water at the same time. my tanks range from 55gallon to 265gallons.

 

[d0nuT]

I have a 20 gallon and I do about 30% every week, including a gravel vac

D

 

[RTR]

I do weekly changes, 33-50% depending on stocking and planting. Some of my tanks are very lightly stocked, other more normally stocked, but none are over-stocked. All are over-filtered.

 

[firefly]

The old school of thought is not to do so many water changes, and don't gravel vac too often, as you will mess up biological filtration. This is true if you still run a UGF as the only filter. Hewever, with hob filters and especially the biowheels, this is really not as much of a concern as it used to be. A lot of what your tank needs depends on how stocked it is, it's size, your filtration and how much you feed, live plants or not etc. Generally now a days, more is considered better. I usually do about 25% a week, and do gravel vacs every other week or once a month (depending on the tank load, plants etc.). It just depends. Daily usually isn't necessary, though I"ve had times where I did need to do that (usually when growing out a bunch of baby snails). IF you can't manage weekly, try to get at least every other week in, and then do more water (50% or so). Yes, you will probably get a bajillion different answers to this question, which just shows you that there is no one exact right way. HOwever, I tend to agree with the new thought that more is better. And, my first line of defense if I notice ailing fish is to perform a water change of about 30%.

Emily

 

[RTR]

Actually, if you are running UG, frequent gravel vauuming and the associated water changes are even more important, as that is the only way to keep that filtration technique working well long-term.

 

[anonapersona]

nitrates

You can use the build-up of nitrates as a clue to the need for a water change. You can determine the size of the water change by the rate of build up.

For example, pick a target nitrate level. A more careful aquarist will often shoot for 20 ppm nitrate as a maximum. (Obsessive types may shoot for 5 or 10 ppm, very casual types may think 40 ppm is OK)

Pick a water change schedule. Whatever works for you. Once a week, once a month, once a day, twice a day, whatever. Test the tank, change enough water to reduce the nitrates to a point where on the next scheduled water change, the tank will only be at the maximum.

You will eventually find out how much nitrate buildup your tank has normally. It will depend on how many fish, how much you feed, how dirty the filter and gravel is allowed to get, whether the tap water has any nitrate.

If you have live plants, which consume nitrates, you cannot rely on this method but if you kep plants, you will be doing regular water changes for different reasons.

So, for example, I test my tank and find nitrates at 20 ppm, my maximum target. I change 50% of the water, tap water has no nitrates, so tank is now at 10 ppm. In 10 days, the tank is at 25 ppm (I was out of town). I can either do a regular 50% water change, reducing it to 12.5 ppm and do the next water change a bit sooner or do a 60% water change reducing it to 10 ppm.

 

[TwoTankAmin]

Nitrate readings can be an unreliable guide for water changing for a couple of reasons. Firstly, nitrates are not the only unwanted item a water change removes. Disolved solids are also building up and nitrates wont reveal them. Secondly, if you run live plants you will often experience low nitrate readings, especially in higher light level heavily planted tanks. In some planted tanks it is necessary to add nitrates rather than to remove them.

I have been fairly religious about doing 30-40% water changes weekly on most of my tanks. However there are always exceptions- discus need more frequent changes and fry even more frequent ones.

As a rule of thumb change water more often rather than less often on tanks which are smaller or which are heavily stocked and which have no live plants. Remember that fish need two things to thrive in an appropriately sized and stocked tank- good food and clean water.

 

[Kasakato]

50% every week. Nitrate is just another test like ammoina or nitrite that needs to be watched. Its not the best guide for water changes. With most fish weekly changes is more then enough.

 

[rich311k]

I do 50% once a week on my 46 gallon tank. I do 50% twice a week on my 75 gallon tank. There is an oscar in there and he is quite messy, to say the least.