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Water Changes and Ion exchange Resin chemistry (Algae)
Matt,
The idea behind water changes, is that you are replacing missing ions,
and removing unwanted ones. But this is only true if the water you are
replacign it with is good quality water. And I believe that BBA a red algae
is due to high phosphates? Try some Duckweed, it's a personal favorite in
limiting phosphates, as I can't afford to add any more bioload with algae
eating fish as it is. (no, none of my algae eater prefer algae to live worms
:-P )
I do 20 gallon water changes on my 75 gallon tank (actually only has
maybe 50 gallons max of water, the rest is filled with substrate, plants,
wood, fish etc...) every two to three days, and I think that is the upper
limit on water changes for a hobbyist. But I only change the water as I see
necessary to keep algae at bay. I use RO/DI water remade with Calcium,
magnesium and trace elements in a commercial mix. However, as far as fish go,
all you need is Calcium and Magnesium, as they do not absorb/adsorb any
nutrients through the water (except oxygen, and water). Only plants
absorb/adsorb nutrients through the water. Fish on the other hand must be fed
their vitamins. But I think my comment is argueable, as Many Discus raised in
too soft water get what is commonly known as "punk Discus" that is their
dorsal spines aren't fully connected, this is due to being raised in too soft
water, and/or not getting enough vitamins when they were being raised, and
there is NOTHING you can do with fish after they are 1.5" big, if they have
spikes at that size, they will ALWAYS have their spikes... :-(
Some Discus Breeders do 50% water changes daily, but that is usually
only the circumstances when they have nearly perfect water coming out of the
tap (i.e. southeast Asia where no chlorine, soft water etc...) Some breeders
run an open system, that is constantly running new water through their
systems. On the opposite side, some people never change their water.
Water Change alternatives: Ion Exchange Resins
If you are able to test for all elements which would be harmful to your
fish and plants, then there is no need to change water, merely only add or
take out what is necessary for their health. On the other hand, if you don't
have the tools to measure anything and everything that can be toxic or
harmful to your plants and fish (I believe that only one of us with a mass
spectrometer does :-P ) then it is necessary to make a bet, that at a certain
point, some ions will be out of proportion.
Another option is Ion Exchanger resins (H and OH, not to be confused
with cheaper Sodium exchanger resins) which some reef aquarists do more than
freshwater people do (because Reef tanks have plenty of Alkalinity to
spare). They run a Cation exchange unit (not a mixed Bed!) through their
tank. Remeber that Cations are the negatively charge ions like PO4, CO3, SO4,
anything that goes second in a chemical formula (ie. the SO4 sulfate ion in =
magnesium sulfate MgSO4) The problem with this, is that before you ever get
to taking out the bad ions, you will remove all of the buffering capacity of
your tank, which would drop the pH to 1 in relatively short amount of time.
The other problem, is that you do not eliminate the toxic Anions (Mg, Fe, Pb,
Fl, Xe :-P for those of you who got that little chemistry joke :-P ) that may
be in great quantities.
To further discredit the idea of simply say, running a "Tap Water
Purifier" cartidge (a H+ and OH- mixed bed Ion exchange resin also called a
"strong base and strong acid" ion exchanger, as opposed to a weak ion
exchanger resins which in genetics they use for removing certain long protein
chains I belive) through your system, is that the process of taking certain
ions is not a selective process (except for some heavy metal resins which are
absurdly expensive, and not meant for hobbyist use, only for large scale
water treatment? right Wright? or who ever is a certified water treatment
specialist?). This means that the resin will take out everything that is more
postively or negatively charged first, and take less electronegatively (or
postively?) charge last... And guess what? that's right, our problem ions
PO4, NO3. or most commonly problematic ions are the last ions to be picked
for the Resin Ball team :-)
Anyone know of a good source for H+ Anion and OH- Cation exchange resins?
Anyone done a DIY Ion exchange resin system? I'd be interested in hearing.
All chemists, feel free to thrash my beguiled General understand of
Chemistry, though I think I got the general idea down. Hope it helped, Best,
Bill