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I'd love to get a clear explanation of how to correctly do a water change... how much how often. I recently set up a 20 gallon freshwater tank and I am going through the cycling process. Does sweeping the gravel consitute a water change?

Thanks,

I do a weekly water changes of about 30% in the 5ft, the Betta tank about 40%.

A little tip I have a small strip of sticky tape on the side of both tanks and I syphon to this mark, this means I remove the exact amount required, no guess work required, very simple but effective method.

All my prepared "dechlorinater added" water is stored in 15Lt containers for one week the main reason is to prevent White Spot entering the tank.
With the 5ft tank I use a large syphon and syphon to the base of the tank along the front only as the rest of the tank is either fully planted or rocks & driftwood. the water is also heated before it it is added to the tank. I do this by placing the water containers in hot water in the laundry trough. When the warter cools down it is them taken out to the garden.

The Betta tank is impossible to do a gravel vac therefore I wave the syphon hose over the substrate this also does a very good job.

Have a look in [link=My Profile] http://www.fishprofiles.com/forums/member.aspx?id=1935[/link] for my tank info

Look here for my
Betta 11Gal Desktop & Placidity 5ft Community Tank Photos

Keith

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Hi,
That's an interesting question. Thanks for asking!

Water changes, first lets discuss the reasons for them.
They are our way of imitating natures' water changes,
and that is rains, or floods. In a sense a "rain" could
be likened to anything from a 10% water change to say, a
30% water change. A flood could be compared to anything
from say, 50% to even as much as the whole tank.
As tanks age from day to day, we "top off" our tanks to
compensate for evaporation. As the water evaporates, the
organic waste products and any salts simply condense or
become stronger as only the water (H2O) evaporates leaving
behind all the contaminates. When we do a water change,
we remove, and in a sense, dilute some of those organic
waste products from the tank and replace it with
fresh water.

Now, how often we do a water change?
That depends on who you ask. In essence it boils down
to a matter of convenience, and the owners sense
of responsibility. Some do it daily either with an
automated system, or weekly, or biweekly, or monthly.

How often should we do one? I'd say once a week. But,
that too depends - upon the bio-load of the tank. If you
have a 20G with just a few tetras in it, then every other
week or two would be fine. The body mass of the fish and
with regular small feedings, does not create that much
waste products. However, if you have say, baby Oscars
in that tank or some larger fish, then the mass of the
fish creates far more waste products, and the water
should be changed, at least weekly.

One way to gage how the tank is doing is to test the water.
Test weekly for pH, Ammonia, Nitrite, and Nitrate. Once
a tank is cycled, you should never see any Ammonia or
Nitrite readings. If you see your pH dropping, while the
Nitrate is climbing, you have started into a cycle that
you need to stop. It can lead to something called "Old
Tank Syndrome" which will be covered later on.

As the fish live in the tank their solid waste products,
along with excess fish food, dead plant matter, and if
there are snails, the waste products from them too,
accumulate on, and between the grains of gravel in the
tank. This detritus, must also be cleaned out on a regular
basis. What better time than at the same time as a water
change? The gravel bed (substrate) is the main
location of the bacteria colonies that support the Nitrogen
Cycle of the tank as well as a host of other colonies.
The surface of each and every grain plays host to these
colonies, as do the sides of the tanks, the surfaces of
any ornaments and the "media" inside your tanks' filter.
If you clean a large area of the gravel at one time,
or all of the gravel at one time, you will weaken
the colonies and the tank may have to recycle again.
You don't want that to happen. The best way to prevent
that is to look at your tank, and mentally divide the non
planted parts of the tank into four sections. With each
water change, clean a different section.. That way in
four water changes, you have cleaned the entire tank.

If your tank is heavily planted, and the sections are
very small, then you will want to swirl your hand
(waive your hand) over the planted sections to raise
the detritus up into the water where the siphon and
filter will trap it and remove it.

How to do a water change?
It can be as simply as dipping a cup or two out of a
"Nano tank" or sticking the end of a hose of some sort
into the tank and starting a suction Or, you can use
a commercial product such as the "Python" brand siphon.

Personally, I prefer a Python as it takes 90% of the work
out of changing the water and cleaning an aquarium.

Once the siphon has started and the tank is starting
to drain with the Python, push the end of the siphon
into the gravel right down to the bottom of the tank
or to the top of the UGF filter plates. The gravel
will be drawn up into the clear plastic mouth of
the siphon where it will swirl around.
This scrapes one grain against another and scrubs
much of the detritus off where it is carried away and
the clean gravel drops back down to the bottom of
the siphon.
Lift the mouth of the siphon up and you will leave small
"Cookie cutter" sized piles of clean gravel. Repeat
the process until you have the entire section cleaned.

Now, with a newly set up tank, that is still cycling,
you should not do water changes or gravel cleaning.
The bacteria colonies are still getting started and growing.
They start on, and grow by living on the
waste products in the tank. If you clean the tank
or dilute the water, you will prolong the time it
takes for the tank to cycle. That being said, you do
have to test the water daily. Check the Ammonia,
Nitrite, and Nitrate readings. Once the Ammonia starts
to read something other than Zero, it can climb as high
as 6. Likewise once the Nitrite starts to read
something other than Zero, it can climb as high as 10
or more in 4-6 weeks. Nitrate readings can climb into
the hundreds (more on this later).
If you are doing fish-less cycling, then follow
the directions and continue to add ammonia till you
reach the point where no matter how many drops of
ammonia you add, the ammonia AND nitrite continue to
read 0. At that point the tank is cycled.

If you are using HARDY fish to cycle the tank, watch
the fish daily, for signs of distress. Gasping at the
surface, laying on the bottom, not eating, laying on
their sides gasping, all are indications that you need
to immediately do a partial water change of 10-20%.
That means that the concentrations of ammonia and, or
nitrite has gotten too high and are killing the fish.
If you don't see those symptoms, then do not change
the water. Wait until your tests for BOTH Ammonia
and Nitrite read 0 before doing a water change.

I have mentioned high nitrates a couple of times.
In a fish only tank, you will want to keep the nitrate
reading down to less than 10. If you have plants in
the tank then keep the nitrate reading down to around
10. Nitrate readings of 40 +/- indicate a tank that needs
cleaning. That includes a water change and gravel
vacuuming. Remember to do it a section at a time
to prevent the tank from recycling. If you ignore your
tank maintenance you can reach a point where the nitrate
reading is higher than 100. This is called Old Tank
Syndrome. It is the result of an accumulation of waste
products to the point where the organic acids are so high
that the pH will actually start to drop as the nitrates rise.
Folks who have a perfectly happy tank full of fish will
decide to add a couple of new fish, and they die for
"some unknown reason" within a couple of days to
a week of being placed in the tank. They can't figure out
why the new fish die and the old fish are happily swimming
around and eating normally. The reason for that is that
the "old fish" have "grown up" in the progressively
worsening water, while the new fish were just "dumped"
into the septic tank. Don't wait for the nitrate reading
to be that high. Keep vacuuming the gravel, a section
at a time with each water change.
Along with water changes, another way to control
nitrate is by keeping live plants in the tank. They use
the nitrate, taking it out of the water, for growth.
Some floating plants are particularly good for this and
as they grow and cover the surface, they help control
the nitrate. Fast growing stem plants also help control
the nitrate within the tank.

I hope this helps.
Frank



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Frank, thanks very much. I copied and pasted your post into a word doc and printed it off... Everyone here is so helpful. Awesome, thanks! We have one of the gravel vac siphon deals. I was going to use that for water changes...