Hornwort vs. Green Water. Add fertilizer?

[CalmedByFish]

I have a 20 gallon, about 1/2 full of healthy hornwort to combat and prevent green water. But I currently have green water. Been 2 weeks.

I'm keeping the light off for now, except a couple hours of very dim per day to help the fish find their food. 

I've decreased the adult's feeding from 2x to 1x per day, though I shouldn't fast them since about half are preggy, and I can't reduce the feeding for the tiniest fry. 

The tank is bare-bottom, with a ton of MTS, so no food is getting lost. (I also watch to make sure the filter doesn't grab it.)

In the next few days, I'll put a few of my extra neocaridina in there, since they'll help re-process the MTS poo. 

My current question: Nitrate is ~5. Do I add Easy Green to help the hornwort, or leave nitrates low to starve the green water?

 

Edited August 12, 2021 by CalmedByFish

[Mmiller2001]

Green water is caused by too much light in the presence of ammonia. I would keep dosing fertilizer and reduce light intensity or improve filter turnover rates after you have cleared the green water.

[CalmedByFish]

Clarifying questions:

I've heard that when people intentionally try to grow green water, adding Easy Green helps. Would reducing the ppm of ammonia help reduce green water, *regardless* of how much Easy Green is available?

Does "improve filter turnover rates" refer to increasing biological filtration in order to reduce ammonia?

[Mmiller2001]

Green water is linked to ammonia. Unless Easy Green contains ammonia or urea, I doubt it contributes to green water.  

It can be confusing, but ammonia is always present in our water even when our hobby level test kits register zero. When we feed, have dead or decaying fish and mulm buildup, we increase/ spike ammonia in the tank. These spikes are usually undetected and our test kits aren't sensitive enough as well. If these spikes have enough light, they trigger green water.

Increasing turnover increases the rate at which BB can reduce ammonia and also helps to clear mulm.

Edited August 12, 2021 by Mmiller2001

[Griznatch]

 If you are up for it, throw a few daphnia in there. They love green water and are pretty efficient at cleaning it up. Depending on what kind of fish you have in there they'll get eaten. I did have  an issue here my Kubotai couldn't eat the adults because the fish were too small 🙂

[CalmedByFish]

On 8/12/2021 at 3:44 PM, Griznatch said:

 If you are up for it, throw a few daphnia in there. They love green water and are pretty efficient at cleaning it up. Depending on what kind of fish you have in there they'll get eaten. I did have  an issue here my Kubotai couldn't eat the adults because the fish were too small 🙂

Are daphnia simply any microcrustaceans? (I had microcrustaceans of some kind in that tank, but the fish pig them down immediately.) If daphnia are something more specific, how do you get them?

 

[CalmedByFish]

@Mmiller2001 I actually copied that into my document on algae. Thanks!

[Mmiller2001]

On 8/12/2021 at 2:50 PM, CalmedByFish said:

@Mmiller2001 I actually copied that into my document on algae. Thanks!

Here's a great source I use.

https://www.2hraquarist.com/blogs/algae-control

 

[Griznatch]

On 8/12/2021 at 2:49 PM, CalmedByFish said:

Are daphnia simply any microcrustaceans? (I had microcrustaceans of some kind in that tank, but the fish pig them down immediately.) If daphnia are something more specific, how do you get them?

 

They are small crustaceans, commonly called water fleas. I got mine as a culture on line. I think Cory has an article on keeping them.  Here it is https://www.aquariumcoop.com/blogs/aquarium/daphnia-culturing-how-to-raise-daphnia?_pos=1&_sid=c82b1c14a&_ss=r      I thought there was a youtube video as well?

Your fish if they are at least as big as an adult guppy, will probably eat them before they reproduce . My small rasboras had a hard time eating the adult daphina, they were too big. Daphnia can make green water crystal clear in a day if you have enough of them. However, with no predators the culture can crash pretty easy. I had mine in a ten gallon and I would just dip some out every day for my other tanks. I eventually needed the daphnia tank for excess guppies, so I fed the remainder of them to my goldfish...