I came across some of my early notes and thought this might be of use, especially now that it is summer.
NOTES:
• *Remove as much algae as possible by hand (using a fine net or siphon) before and after treatment to prevent the decaying algae from adversely affecting water quality and thereby, fish health. Removal will reduce the nutrient load in the tank.
• *Water changes should always be conducted in conjunction with a gravel clean (utilising a gravel siphon).
• *Chemicals should never be the sole treatment. It should be used only after or in conjunction with management strategies as outlined above.
Suspended green algae
Appearance
• Green water
Cause
• Over fertilising water (PO4+3, NO3-, Fe).
• excess fertiliser, overfed, overstocking (too many fish), insufficient cleaning, insufficient water exchange.
• Too much lighting (artificial or natural).
• Poor water flow.
• Water source with high PO4+3 and or NO3-.
Treatment
• Several large (30-50%) water changes (with gravel clean), remove algae manually, restrict feeding.
• Reduce photoperiod / provide shade.
• Grow more aquatic plants to compete for nutrients and light.
• Provide water movement (aerate/power head/fountain).
• Reduce fish stocking density.
• UV clarifier.
• Ozonate water.
• Use flocculants and then filter out debris.
• Barley straw (added such at aerobic decomposition and allow for colonisation by flora that will consume the algae).
• Barley straw extract.
• Algicide – TetraPond AlgoRem.
• *Ion-exchange resins.
Blue-green algae
Appearance
• Bright green, often aggregates on the surface in the static parts of the pond and tend to collect at the edges.
Cause
• Poor water quality (excess nutrients).
• Wrong lighting.
Treatment
• Large (30-50%) water changes every 2-3d (with gravel clean).
• Use only white light.
• Chemicals – ZMF Algo-stop fix.
Blanket weed & Duck weed
Appearance
• Minute twin leaved plants with well-developed roots.
Cause
• Pest weed introduction from contaminated source water.
Treatment
• Algicide – TetraPond AlgoFin.
Brownish algae
Appearance
• Thin and carpet-like.
Cause
• High silicate level in the tap water.
Treatment
• Increase frequency of water change (with gravel clean).
• Lower stocking density.
• Use only pure white bulbs.
• Use alternative water source.
• Use rainwater (ensure it is collected safely to avoid zinc or aluminium toxicity).
Brown algae
Appearance
• Look like rust on leaves, glass, rocks.
Cause
• New aquarium with very hard water.
Treatment
• Should disappear over time.
• Decrease water hardness using distilled water or rain water.
• Use reverse osmosis water.
Red algae (Rhodophyta)
Appearance
• Black colour that changes to red when put in alcohol.
• *Prefer harder more alkali water.
Cause
• New aquarium.
• Poor plant growth (Cause sand substrate, insufficient nutrients).
• Wrong lighting (too much blue spectrum).
• Add blue food dye to water to absorb/reflect the light.
• Using yellow bulbs (bad for plants, indirectly good for this algae).
Treatment
• There are no chemical treatments available because the structure of the red algae is very similar to water plants.
• Manually remove affected leaves from water plants.
• Encourage growth of water plants to reduce red algae by using fertilisers (TetraPlant fertilisers: Crypto tablets & FloraPride).
• Reduce water hardness and pH.
• Use pure white lighting only.
• Chemicals – Tetra Algizit (beware, stunts plant growth).
Grass-like algae (1)
Appearance
• Green and grassy.
• Grow on all surfaces.
Cause
• Nutrient rich water.
• Too much lighting.
Treatment
• Manual removal by scrubbing surfaces affected.
• Partial water (30-50%) changes.
Grass-like algae (2)
Appearance
• Greeny-black.
• Grow on all surfaces.
• *difficult to eradicate.
Cause
• Nutrient rich water.
• Too much lighting.
Treatment
• Use only pure white daylight bulbs.
• Decrease water hardness.
• Decrease pH.
• Chemicals – Algizit.
Grass-like algae (3)
Appearance
• Brownish looking.
Cause
• Indicator of poor water quality.
• Wrong lighting.
Treatment
• 30% water change every 2 weeks.
• Decrease stocking density.
• Reduce feeding.
• Use only daylight bulbs.
• Add plants to compete.
• Chemicals – Algizit or AlgoStop.
Brush algae
Appearance
• Plant-like, brown/black, grows on all aquarium surfaces.
• *Difficult to eradicate.
Cause
• High iron levels.
• Wrong lighting.
• High pH.
Treatment
• Several part water changes (with gravel clean).
• Use only pure white light bulbs.
• Don’t fertilise with iron.
• Keep pH below 7.
• Use Tetra Algizit.
Black algae
• *These algae grow best at pH > 7.
• *not usually possible to eradicate this algae, but you can reduce it to a minimum.
Treatment
• Reduce KH.
• Reduce pH <7.
Black moss / Black beard
Appearance
• Grows on all surfaces.
Notes
• Very stubborn and difficult to eradicate.
• This algae does not thrive in soft acid water.
Cause
• Poor water quality.
Treatment
• Several large water changes (with gravel clean) to remove fertiliser.
• Reduce KH and pH.
• Manual removal.
• Tetra Algizit (liquidises algae, but may stunt plant growth).
Cloudy water
Appearance
• Whitish-green cloudy water.
Treatment
• Partial water changes (with gravel clean).
• Use only pure white light bulbs.
• UV-clarifier.
Diatoms
Notes
• Fish do not consume diatoms.
• Some diatoms may be toxic.
Cause
• High silicate level.
• Lighting.
• Inadequate water current.
• Excess nutrients in water.
