What causes water to turn green?

[aRmOn]

Hi all.. what exactly causes our cycling water turn greenish? Is it causes by over lighting or due to poor water circulation?

[juggler]

Too much lighting with excess nutrients in the water seems to be the cause.
Do more frequent water change and cut down lighting or lighting period. Can also try some floating plants as shade.

[PeterGwee]

NH4 coupled with loads of light = Green water.

Regards,
Peter Gwee

[aRmOn]

Lighting can be reduced by turning off some lights. How about excess nutrients, what are usually the cause for this excessive nutrients?

[Aeon]

Yes. My experience tells me green water happens when NH4 is high, in new cycling tanks, after filter spoil, bacteria die, etc. Too much light, especially direct sunlight also cause it.

[aRmOn]

Went to NA last Sunday, the owner advised me (sorry don't really know his name) to install UV light. Purchased a 9watt UV light and after two days (running it for 12hrs per day)... my water is crystal clear now. Thats is what I call technology that help in our daily life.

[StanChung]

If I'm not mistaken, your plants leaches some green/brown nutrients into the tank IMHO. This can be noticed if you put plants into a bag of water and into the dark for a few days. This is different from green water.

[aRmOn]

If I'm not mistaken, your plants leaches some green/brown nutrients into the tank IMHO. This can be noticed if you put plants into a bag of water and into the dark for a few days. This is different from green water.

Are fissidens, red tiger lotus (if I'm not wrong what people call it) and HC leached? This are the plants that were in my tank but like I posted before UV lights do really help to crystal up my water. Really appreciated for those that have given advised and shared experience. Thanks all.

[StanChung]

They do a little but I suspect not enough to cause the water to go green unless you have a large portion of them rotting.

[gummynut]

i've been trying to culture green water without success by placing a container of tank water from water change by the window (for sunlight). maybe i need to supply some ammonia into it.

[aRmOn]

Thanks StanChung, will note and make sure that my plants don't rots.