Re: Water quality - ? test for bacteria in deionised water

From:Lee & Peggy Wenk <>

When was the last time someone changed the filters at the DI plant?

That's what happened to us. It slipped through the cracks for about
a year, until we started to have "bug" problems. Add in an insult to
the water of new contruction to the pipes shaking loose old scale
and gunk, and put in a dash of forgetting to close the loop on
one new addition (so one set of pipes dead-ended in a back-water
situation), and top it off with an  increase in a chemical in the
city water that would reduce the  amount of lead leeching out
of old houses but results in an increase in bacteria in the water,
and we had prime breeding conditions for bacteria and the making
of a year long battle to reduce the bacteria  in the DI water.

Definitely test the water at the DI source. 1 mL of water on a
petri dish would do it, or the bacteria "paddles" that someone
else mentioned earlier.

Until you can get it under control, there are water filters you can
buy that you screw into the DI faucet tap. Cost about $60 each.
Takes care of the problem locally, but not at the source. Remember
to change these filters, too. The people who supply the filters for
the DI tank can probably set you up with these faucet filters.

Good luck.

Peggy A. Wenk, HTL(ASCP)
William Beaumont Hospital
Royal Oak, MI 48073

----- Original Message -----
From: "Richard Pitman" <>
To: <>
Sent: Monday, January 08, 2001 3:43 AM
Subject: Water quality - ? test for bacteria in deionised water

Hi All,

We had some problems with a Warthin Starry last week. (Is this an
appropriate stain for suspected Cat Scratch disease?) Finished slides were
covered witha background of bacteria. Usual places for these to get in are
either via a dirty section floating bath, or contaminated staining solutions
and/or buffer stocks.

So, we set out to make up fresh solutions, change baths etc. Which lead to
any interesting debate. I had always 'assumed' that water from our
deionisation plant would be bug free. Water passes through a coarse filter
on the supply side, passes a UV lamp, then a reverse osmosis filter, finally
through an ion exchange column. Vendor claimed water  quality better than
double distilled. System should be sanitised with hypochlorite every so
often, not done this recently, was done on installation 12 months back.

Other suggestion was that we obtain 'sterile' water from Micro. This has
been through process above, then autoclaved. Any bugs would still be there,
but dead. They'd still stain up, though ?

Is there a quick test I can do to see if bugs are present in the holding
tank ? Suggestions range from sending sample to Micro to see if they can
grow anything, or evaporating some water onto a slide, then doing a Gram on
the deposit.

Any thoughts please,


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