Fish: Re: [tropical fish club] scum

That "oil slick" aka surface proteins that collect can come just from the dust and other particles in the air in the room. If there's not enough circulation at the surface of the water then it prevents proper oxygen exchange which makes the problem worse. I have had many tanks over the yrs that didn't even have fish in them so no food, etc. yet they had the same problem until the filter was set up and running. Stagnant water collects all kinds of stuff at the surface and if the filter is pulling in and putting out water only in the lower part of the tank then the upper part will be stagnant or with very little movement which allows these proteins to collect. If you note in the original post the only change mentioned to this tank was the changing of the type of filter and the problem didn't exist prior to the new internal filter. That's a clear indication that this is a circulation problem.

The surface proteins can be removed by manually skimming with paper towels. This is done in saltwater nano tanks where this is a common problem and there are no decent skimmers available for the smaller tanks. The issue with just surface skimming to fix the problem in a freshwater tank is that the cause of the problem remains... lack of circulation at the surface, and it gets to be a pain in the butt to do it all the time, plus it can be a bit messy.

Dawn

Dawn Moneyhan
Aquatics Specialist/Nutritionist
To learn more about me go to
http://www.helium.com/users/449334

--- On Thu, 5/2/13, sevenspringss@wmconnect.com <sevenspringss@wmconnect.com> wrote:

From: sevenspringss@wmconnect.com <sevenspringss@wmconnect.com>
Subject: Re: [tropical fish club] scum
To: tropicalfishclub@yahoogroups.com
Date: Thursday, May 2, 2013, 12:52 AM

Dave,

You shouldn't have any more of a possibility for scum on the water by using

an internal filter than you do by using an external filter. As you're

concerned with sufficient gaseous exchanges through the surface though, we need

to clarify exactly what is meant by scum on the water, as I first pictured a

sort of sudsey residue on the surface -- which often indicates phosphates

-- but I'm beginning to think you mean a condition like an oil slick.

Still, an internal filter should not be thought of as promoting this,

Most often, this comes from decay -- if it doesn't come directly from oily

foods that are given, which I tend to doubt your giving. Removing the top layer

of water will not reduce contaminents in the tank, if by that you mean the

first 2 or 3 inches of water. If you can somehow remove the actually

surface of the water along with this film, this will reduce the problem greatly,

but will not address the source of the problem. I still feel that the

problem is coming from the food, even though it may be a more acceptable type.

Likewise, high phosphate oftem comes from the food if it's not balanced

correctly. Let us know what your feeding and in the interum, try increasing the

aeration -- either by having your filter run a bit faster or by installing an

airstone.(requiring an air pump).

Ray </HTML>

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