ScapeLyfe provides our readers with in-depth news and information about Aquascaping, and we cover everything from daily maintenance and water changes, to long-format coverage of substrates, filters, and more. Read more about what we do. Biofilm In Planted Tanks — Biofilm: Surface Scum in Planted Tanks

Biofilm: Sur­face Scum in Plant­ed Tanks

Issue 003/ April 14, 2018
Biofilm is a com­mon prob­lem, espe­cial­ly in plant­ed tanks. Even the best aquas­cap­ers do occa­sion­al­ly see it in their aquar­i­ums. Here’s how to solve it!

Biofilm is a com­mon prob­lem, espe­cial­ly in plant­ed tanks. Even the best aquas­cap­ers do occa­sion­al­ly see it in their aquar­i­ums. While there is no defin­i­tive answer on the exact caus­es and com­po­si­tion of biofilm (there can be dif­fer­ent types), there are a few com­mon opin­ions based on anec­do­tal test­ing and research:

Where Biofilm Comes From

The aquar­i­um com­mu­ni­ty hasn’t com­plete­ly agreed on the exact com­po­si­tion of the sur­face scum’, or biofilm, that appears in tanks. There are a few opin­ions on the matter:

Biofilm is the carbs/​lipids excret­ed by stressed plants

A pop­u­lar view­point (sup­port­ed by var­i­ous anec­dotes) is that biofilm only forms when plants are unable to take in enough nutri­ents from the water col­umn, whether due to high­er alka­lin­i­ty or a sim­ple lack of prop­er dosing.

Biofilm is a tem­po­rary symp­tom of new tanks

Anoth­er view­point is that biofilm is sim­ply a phase’ that some new tanks pass through as the bac­te­ria matures and reach­es an equi­lib­ri­um. Accord­ing to this the­o­ry, once the tank matures, the biofilm should dissipate.

Solv­ing The Problem

So, how do you fix it?

Well, the aquar­i­um com­mu­ni­ty has a few dif­fer­ent opin­ions on the exact con­di­tions that cause biofilm, but it’s gen­er­al­ly agreed that you can do three things to solve it once and for all:

Increase your O2 lev­els in the water

Biofilm has been known to form at the water sur­face because it’s seek­ing high­er O2 con­cen­tra­tions than what it can find dis­solved in the water. Sur­face agi­ta­tion with a pow­er­head, fil­ter out­put pipes, or any­thing else that agi­tates the sur­face will increase your O2 lev­els. If you’d like, you can also use a gad­get like the Twin­Star Nano to get more O2 into your water.

Increase your water flow

Weak flow in the aquar­i­um has also been shown to be cause of biofilm. Ide­al­ly, your fil­ter out­put should be at least 10 times the size of your tank to pro­vide plen­ty of turnover and flow. It’s also a good idea to check for dead’ spots where water isn’t mov­ing. If you find any, a pow­er­head is a great solu­tion for this.

Check your dosing

Final­ly, check that you’re pro­vid­ing the prop­er nutri­ents for your plants. Plants nat­u­ral­ly pro­duce car­bo­hy­drates and lipids as a part of pho­to­syn­the­sis. If they’re hav­ing trou­ble ingest­ing nutri­ents from the water, or there sim­ply aren’t enough nutri­ents, this pro­duc­tion of carbs and lipids is increased, which can lead to the biofilm on the water surface.

Biofilm can be mys­te­ri­ous when it appears, but if you increase O2 lev­els, fix any weak flow, and check your dos­ing, you should see it dis­ap­pear with­in a day or so.

What’s your solution?

We’ve all prob­a­bly encoun­tered biofilm at one point or anoth­er in our aquas­cap­ing. What did you do to solve it? What do you find caus­es biofilm to occur? Let us know in the comments!

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