re: surface scum
To: Aquatic-Plants at actwin_com (Aquatic-Plants)
Subject: re: surface scum
From: "David W. Webb" <dwebb at ti_com>
Date: Tue, 19 Mar 1996 17:19:02 -0800
Conversation-Id: <BMSMTP8272837401a0206807 at dlep1_itg.ti.com>
>From: aljem3 at attme_cnet.att.com (James E. Morehouse)
>I'm posting this for a friend...he has a 125 gal that he's had established for
>some time with 2 aquaclear externals and UG filters w a (relatively) coarse
>gravel substrate. He has just started to get the tank 'plant-ready' with the
>addition of VHO lighting and CO2. Just prior to adding the above, he noticed
>the appearance of a thin surface film, whitish in color. He's not aware of
>any changes that were made that could be tied to the appearance and the tank
>has been operating (with a fairly heavy fishload and no plants) for about 2
> I noticed a
>recent post (on phosphate) where someone (Dave?) mentioned that feeding with
>high meat content foods could increase phosphate levels...I know that Gary
>(the friend with this problem) has been feeding a homemade mixture using liver
>or beefheart in rotation with other foods for years..can this be a cause? he
>does 25% water changes weekly.
Prior to building my trickle filters (now settling tank systems), I had this
problem too. It didn't matter if I fed flakes, bs, discus formula, or
whatever. I don't know exactly what caused the problem, but I suspect it
involved a bacteria, protein, and calcium (I got hard water deposits as well).
It may have also been due to a fat and/or phospholipid buildup. All of this is
pure conjecture. I have no idea what it was, I just learned what to do to
eliminate it after a while.
When I installed my first good surface skimming overflow, I was surprised to
watch (from below) all of the scum on my water's surface quickly break up and
zip down the drain. I've never had a problem with surface scum since unless my
filtration system shut down temporarily. If the filter shut down, I had scum
pretty quickly. I also had a phosphate problem, probably because of the meat
content of the Discus Formula that I fed. According to my high-school biology
class from way-back-when, cellular membranes (animals and bacteria) are
primarily composed of phospholipids. Cell walls (plants) are primarily
composed of cellulose.
I only had this problem when I configured my tank for plants (eliminated the
air-driven UGFs). I suspect that the splatter from the air bubbles popping may
have helped cake the inside of my hood with the scum and reduce its impact on
the water's surface.
I don't have any surface scum on any of my tanks now, but I have surface
skimming water management systems on two of them, and my micro only gets fed
once a week.
David W. Webb
Enterprise Computing Provisioning
Texas Instruments Inc. Dallas, TX USA
(214) 575-3443 (voice) MSGID: DAWB
(214) 575-4853 (fax) Internet: dwebb at ti_com
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