Using green water to export nitrates and phosphates.

My aquarium isn't planted and is bare-bottomed. I just have sponges in a sump and the water feed to the sump goes through tightly packed cotton wool first to remove detritus. I have a Tunze nanostream to keep detritus in suspension.

Yep, I run my freshwater tank the same way you run a marine tank

My tapwater has chloramines in it. I fill a large bucket with tapwater in the garden and add a pinch of ascorbic acid (vitamin c) to break the chloramine. It takes 24 hours for the resulting chlorine to gas out on it's own and the water is ready to use.

If I Ieave the bucket outside for a few days uncovered, the water turns green. My aquarium tank water is crystal clear. I added the green water to my tank and my cotton filter turned green. The water was clear again within a few days.

I haven't tested my water for a while as I'm very understocked, but I think the green water must be absorbing the nitrates and phosphates in my aquarium.

 

Hi

I really don't know how much the free floating algae in green water would consume nitrates and phosphates but it would be some amount.

 

That's the thing. If it can turn the tapwater in the bucket green within 3 days, it must be powerful at uptaking nutrients.

 

Not very practical though. Higher plants, especially emersed (like Pothos) are far more effective.

I would do some testing for sure, just so you can proof your assumptions.

 

without strong light, the algae won't consume nitrogen/phosphate. the algae trapped by the cotton filter won't be helping. and once they die due to lack of light, they'll release nitrogen into the water.

you can just grow a wall of algae like this 75 Gallon Tank - I've Done It, Perfect Cycle | Cleaning and Maintenance Forum | 403644

 

I have 300w of RGB LED strips over my aquarium.

The cotton is changed daily, so I doubt the algae has time to break down. Like MacZ said, it's just an assumption until I test the water.

 

I have also said using a house plant is much more effective. And more economic.