Re: [RML] Water changes.

jazep at
Sun, 8 Dec 1996 21:05:04 -0700 (MST)

Yo, Dude! :-) Welcome aboard.

Don't worry about your typing/spelling "problems," you couldn't be as bad
as Roy-boy. ;-) (Sorry, Roostah; couldn't resist!) So long as you don't
mind a friendly dig or two, when you make a really funny one, you'll soon
find yourself right at home. :-)

> What sort of biological filtration do you have?? One reason for performing
> water changes is to reduce nitrate levels, the other is to remove decaying
> organic matter that would normally be processed via the Nitrogen cycle.

If, as you have stated, your tank's heavily planted, you may find that
you'll never have a serious nitrate problem. ... Unless something goes
wrong w/ your system. Vigorous, growing plants will take up much of the
nutrients in the water before things get that far.

As for what else needs to be diluted, the organic decay is but one thing.
Fish and plants release and take up things as they grow and respire. Water
changes dilute many of these things, such as hormones, to keep them from
building up to levels that might cause problems (ie: some fish, when
growing, produce chemicals that can inhibit both their own and other
fishs' growth rates, thus causing some stunting to occur). Many things
also need to be replenished, esp w/ the plants. You can add nutrients
(minor ones and iron), but changing the water does the trick for a number
of the trace elements, depending upon what's in your water supply, of
course. :-) It is my plants that "tell" me when I'm past due for a water
change, much more so than the fish.

> I must admit I pay little attention to phosphates. One of the 'plant dudes'
> on the list may be able to comment on the effects of phosphates in the
> aquarium.

Ahem. You mean "dudettes," don't ya?? ;-) See above for the benefits of
water changes for plants.

Phosphates are thought to be *the* limiting factor in plant growth in the
wilds. The plants that they most often limit, however, are the algaes when
it is in your aquarium (prob to some degree in nature, too, but there are
"higher" weeds that respond to increased P levels as well). (OK, Gary.
Commence w/ the correction/enlightenment re the proper chemistry of this
-- you all know I s**k at the down-and-dirty details of this gawdawful
chemisrty sh**. ;) )

Basically, this boils down to the aqurist wanting to keep the P levels as
low as reasonably possible in the aquarium. Excess P leads to excess
algae. Not quite as deadly in FW as it is in Marine setups, but algae,
uncontrolled, can damage the plants. When P levels are low, the higher
plants will usually outcompete the algae for it, thus limiting problems.
Phosphate is found in all kinds of stuff, esp in the foods that one uses
to feed the fishies. Frequent partial water changes (providing that the
new water is not a major source itself) will keep levels from getting too
high. When you noticed an increase in P levels in your tank, did you also
see a greater amt of algae? If it gets too high, you can get quite a
bloom! :-)

Sorry if this isn't the most clear explanation of things you've seen. It's
been a long weekend... :-)

Julie <><

PS: Hey Hughes (sp?)! You out there?? Bet you could 'Splain things a lot
better'n me..... :-)