Algae Problem

[STEWARDSONS]

my brother has a 90ltr brackish tank with a green spotted puffer fish in.

he started to get green algae growing and its not going away. he has cleaned it off but it keeps growing back.

he runs marine bulbs during the day and blue led lights a night.

i suggested doing a weekly 25ltr water change rather than 2 weekly and also to turan all lights off at night rather than leavng the blue led's on.

any other ideas?

 

[OldMan47]

I am not seeing the problem. Algae growing on the glass is a good thing for the fish. It is a bit unsightly so it is worth cleaning off the glass that you use to view the fish through. If you want to reduce algae growth, you need to reduce the lighting to an extent. Does the tank hold any real plants? If not, try just turning the lights on when people are present to view the fish.

 

[STEWARDSONS]

he has one live plant in there.

he has looked into getting a bristlenose to clean it but its likely to get eaten unless its on the large size.

i will try to upload a photo of it

 

[waterdrop]

Long hours of lighting in the day will be the main cause of excess algae. Take away an hour of day lighting and see if things get better, then another hour etc. WD

 

[ian]

that looks like Blue Green algae to me.

to quote James planted tank

Often caused by very low nitrates. It is fairly common to have it growing in the substrate against the front glass from where it can spread. Sometimes it appears with new setups that have had light and ammonia present at some point. Dirty substrates and filters may also bring it on. Poor water circulation is another possible cause.

and how to fix it...

A blackout is the best method for this. Clean out as much of the algae as you can and do a 30 to 50% water change. If your nitrates are low then add some potassium nitrate to get levels to 20ppm. Remove CO2 and add an airstone. Turn off lights and cover the whole tank so no light can enter. Leave it for 3 to 4 days. No peeking and no feeding - fish will be fine without food for this period. After 3 to 4 days remove the covers and do a 30 - 50% water change. Remove airstone and start CO2. You will need to dose nitrates to keep them dropping too low again. Make sure your substrate and filter doesn't become too clogged up with mulm and also make sure you have good water circulation around the whole tank.
Another option is to treat with Maracyn which is an anti-biotic. Seems to work well but may affect the biological filter. In the UK it is illegal to purchase Maracyn without first getting a prescription for it from a vet.
If the BGA is originating from the substrate place some dark tape on the glass to hide the substrate from direct light.

also, that plant looks non aquatic, it looks like a type of Dracaena. I would take it out as it will rot, causing ammonia spikes.