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Re: Electrolyte Supplements
Doug Cushing wrote:
>
> Now that I've got my TDS meter and I know that my water is not suitable for
> most of the fish I'm keeping, I've purchased an RO/DI system. Can anyone
> tell me what, if any, supplements need to be added to RO water before it
> hits the tanks? Thanks in advance.
Rule one! Never use straight, undiluted RO water unless you really
understand the chemistry of nitrites, etc. RO/DI is far more lethal than RO
alone, BTW, as it is totally unbuffered. IDK why they sell such units to the
hobby.
99% of the time, your tap water is the only thing you need to add to provide
appropriate buffering, micronutrients, etc. for fish and plants. If the RO
unit has a proper carbon filter, you don't even need to dechloraminate that
part of the mixture with "Amquel" o/e. Avoid creating difficult-to-repeat
chemical soups that the LFS will advise. Tap water is usually a much better
mix of electrolytes than you can buy, anyway.
If your tap water has unusually high Ca and Mg levels (i.e., is very, very
hard), you may wish to add a bit less tap water, and bring the tds up to
osmotic-comfort levels with a little added plain salt. [Pickling, rock, and
other pure forms of NaCl can avoid the gill-clogging silicates of the more
expensive (aka "iodized") table salts.]
I'm not sure how the tds meter told you that your water wasn't suited to
your fish.
Most of our fish will live and breed in fairly high tds water, and only a
few newly-imported rainforest fish seem to require much special adjustment.
After a generation or two in domestic tap water, they will often do just
fine at anything below about 700 ppm tds. The eggs of a few may hatch better
at 400 ppm or less.
The *only* thing that can indicate that your water is unsuited to your fish
is a detailed and current water analysis. That is available for a small fee
from places like Cornell U., but is always free from your water provider, in
the US, if you aren't on a rural well. [Unfortunately many of those local
water suppliers are local governments, and they may consider a
three-year-old test is "current." They have purposely rigged the rules but
won't tell you that.]
The primary purpose of the tds meter should be to stabilize the conditions
for your fish, so you don't accidentally shock them with too-fast change in
osmotic conditions.
New fish from other hobbyists, or the LFS, need to be tested to see if they
can be put in your water, or must be drip acclimated to it. Don't ever make
sudden 2:1 or greater changes in tds.
RO water is extremely dangerous if your fish are suddenly exposed to it
after being in high tds water. I prefer to use straight (dechloramintaed)
tap water in most of my tanks, as it is very easy to make a mistake and kill
or injure fish with abrupt changes in tds. I have only a few tanks where I
add RO water to deliberately lower tds. [YMMV, as my tap water averages
about 270 ppm.]
Most of my RO use is for hatching bbs and eggs. It "wets" better than tap
water.
Yes, the native water conditions are often lower tds, softer, and lower pH
than my tanks. Those waters are often free flowing and undergoing constant
renewal in a way I cannot duplicate in a tank, too. *Stability* from
water-change-to-water-change is far more important, IMHO, than exact
duplication of some rainforest stream conditions. Even Nothos come from far
lower tds water than we usually use to maintain them. [Tanganican fish are
one exception, in that they seem to need very hard, high-pH, high-tds water
to do well.]
Good luck. Use the tds meter for the benefits it can bring to a stable fish
environment, and use that RO water very cautiously.
Wright
--
Wright Huntley, Fremont CA, USA, 510 494-8679 huntleyone at home dot com
If it ain't broke, don't fix it -- and, especially,
don't let politicians fix it. ... Thomas Sowell
*** http://www.libertarian.org/ ***
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