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Re: R.O. UNIT
From: Marco Lacerda
Sent: Monday, March 22, 1999 3:48 AM
>I'm trying to start using a R.O. unit in order to get softer water, as
specially blackwater Apisto species are posing much problem with their eggs.
>
>Tsuh Yang from this list suggested one from Kent Marine, but he has no
experience with it...
>
>How should I use the R.O. water? Mixed with normal water?...
From: Fredrik L
Sent: Monday, March 22, 1999 7:16 AM
>I've heard a lot of positive things about RO-units from Kent, seems like a
good unit. I'm using an Aqua-Medic since two years and it's great. I have
fairly soft water so I have yet to change membrane. Even though you probably
have very soft water check out the prices for replacement-membranes. Since
you want to exchange these on a regular basis this is a cost not to forget.
>
>I mix it with some of the waste water which I have filtered through peat. I
have used 1:3 waste-peat-water/RO-water which works fine. I haven't had the
opportunity to try some of the really hard species yet (diplotaenia,
elizabethae, uaupesi...). I know that this setup worked fine for A. gephyra,
norberti and cf. pertensis.
Sent: Monday, March 22, 1999 7:33 AM
>Maybe I should clarify this a little, so not to confuse ppl out there. My
unit wastes about 6 times the produced RO-water. The waste-ratio is
something I can regulate, and I have chosen 6:1because I can then still use
the waste as normal tank water for most species. I don't know if you can do
this on a Kent-unit, but I think it's a good feature.
>
>Take a look at their homepage
>http://www.kentmarine.com/
From: Ryan M. Williams
Sent: Monday, March 22, 1999 8:03 AM
>I have a Spectrapure unit and have been really happy with it so far. I've
only had it for 2 months so time will tell. Their site, if you're
interested, is www.spectrapure.com.
From: Vern Wensley
Sent: Monday, March 22, 1999 8:49 AM
>Hi Marco.Have you thought about useing a deionizer?I have used the Aquarium
Pharmaceuticals tap water purifier with great success.It is rated for 50 to
150 gallons of deionized water,but I can get twice that since my water is so
soft already.I only used it for those ph 5 and under fish which makes it
last a long time before you have to replace the cartridge.The good thing
about it is there is no waste and you can make water at any temp.you want
From: David Sanchez
Sent: Monday, March 22, 1999 8:56 AM
>Don't bother with Kent Marine in my opinion it's a toy. I highly reccomend
the Spectapure line of RO sytems. With Spectapure you get a much better
quality membrane that will give you water in the acidic values right
away...I have a few guys in my local club using RO systems and they have to
mess with the Ph two of them use kent Marine...
-------------------------
My experience with RO units range from the basic Kent model to the severely
over-priced RainSoft in-house units (my mother got suckered into almost
$1000 from them). To paraphrase Will Rogers, "I never met a unit I didn't
like".
Things to watch for:
1. Thin Film Composite (TFC) units usually give you better long-term
performance with a wider range of contaminants than do Cellulose TriAcetate
(CTA) membranes. They are also available in a wider range of flow rates. You
must monitor for chlorine more closely with TFCs, however, as they are
susceptible to breakdown when exposed to it. That's why the carbon is set up
as a pre-filter to the unit rather than post-filter as with CTAs. Keep an
extra carbon block on hand the first couple of times, until you get a "feel"
for how long they last with your water supply and filter rates.
2. Fredrik's mention of adjustable flow rates is an option that's useful if
you have a seasonably variable water supply in particular. This feature can
help extend the life of your membrane, which is undoubtably the single
biggest cost in replacement parts. You can increase the saline-to-pure ratio
as the supply water hardens up and the contaminants won't be forced quite as
deeply into the membrane, making "back-flushing" easier. Speaking of which,
if you go with the Kent (or any other, for that matter, but I know for
certain Kent offers the option) definitely get the back-flush kit with it.
Back-flushing essentially rinses the membrane of surface build-up, and a few
seconds spent twice a week or so in back-flushing helps considerably in
extending the membrane's usable life-span.
3. Replacement parts and accessories for Kent units are readily available
and easily accessible. They also give you a choice of micron sizes with
pre-filters, so you can easily handle the presence or type of sediments that
may exist in your local supply.
4. Since you're asking about a 100 gpd unit, a DI might not be an economical
replacement as you'd be replacing or recharging the DI on a too-frequent
basis. However, Kent offers a unit with a DI mixed resin post-unit which is
quite practical. This configuration gives you the absolutely purest water
available and the DI post-filter lasts a very long time this way. I
personally would opt for this configuration. Such a setup would render moot
*any* posted objections concerning brand differences.
5. The modular design, option availability and accessibility of the Kent
line, as well as its popularity, goes a long way toward a solid
recommedation.
David's comments concerning "acidic values right away" has me wondering.
Since the pH of chemically pure water is neutral, the most common
"contaminant" affecting its pH is, of course, carbon dioxide. Absorbing CO2
from ambient conditions normally results in a pH in the low- to mid-6 range,
a condition often mentioned whenever someone comments on the output of an
RO. For him to pointedly mention this has me asking in return, "What acidic
values are you considering?" If the difference is striking, then I would
wonder how the SpectraPure unit effects this difference.
Finally, there's this question:
From: Edison Yap
Sent: Sunday, March 21, 1999 9:09 AM
>Can the Spectapure line or any Fish Quality R.O. Unit able to produce water
that is good for human consumption?
RO units were originally developed for human use aboard ocean-going vessels
as a means of providing fresh water sources without the volume
considerations and risks involved in long-term mass storage. (As an aside,
this is why the waste water is still referred to as "saline".) Since the
fish are far more sensitive to what's in their water than we humans are, I
can see no reason whatsoever for us to *not* be able to use the output.
I would recommend that you use the output for cooking and brewing rather
than direct consumption, however. Water of such purity can affect things
like osmotic pressure differentials, and drinking it directly and alone can
sometimes produce irritation in the stomach and upper intestinal tract.
FWIW
-Y-
David A. Youngker
http://www.mindspring.com/~nestor10
nestor10@mindspring.com
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