Green Algae In Tank Substrate

[hoyfoys]

Hello,

I have a plant food substrate covered in sand at the bottom of my tank and there is a green algea now appearing between the sand and the glass. I have reduced my light time to 6 hours as the tank gets a fair amount of light from a window. I try hard not to overfeed and have shrimps to clean up the bottom of the tank, when I use a gravel vac there isn't much waste to be removed. I have a fairly highly planted tank.

What can I do to stop this green algae growing?

Thanks

 

[StandbySetting]

Is it s planted tank?

IF it's at substrate level it will probably be cyanobacteria, generally a result of poor circulation and lack of nutrients, mainly nitrate.

 

[hoyfoys]

Yes, a fairly heavily planted tank. It's mainly towards the top of the sand. I have a well specced filter that causes quite a current and turn on an air bubble wall whenever the lights are off (to disperse CO2 at night). My nitrate is fairly low (5-10ppm) should I do a smaller or less frequent water change to keep the nitrate higher? What level would you suggest?

 

[StandbySetting]

Are you dosing any nutrients? What's the tank volume and what filter do you have on it?

 

[hoyfoys]

Not dosing nutrients other than fertiliser once a week. 110L tank with a Fluval U3 filter

 

[StandbySetting]

Which fertiliser are you dosing? Ideally you should be dosing daily, and it sounds like circulation is an issue too.

 

[hoyfoys]

eSHa Cryptoplus Plant Growth Booster, it says 20 drops a week, which is what I dose. How can I improve circulation? I use the underwater vertical outlet of the U3, the fish really like the current and almost surf it! The plants near the algae are moving. How would the current get to the algae when it's under the sand?

Thanks so much