Slightly green water

[Supermassive]

I did a water change today and noticed the water was an abnormal greenish color. Its the first water change I've done since the tank was filled about a month ago. It wasn't very dark, only a slight tint. The tank is empty besides plants and pest snails. I'm not that worried about it. I didn't even notice the color until the water was in a white bucket. But I would still like to know what its from.

Can easy root tabs cause the water to turn slightly green or is my light on too high or too long? I put in about 10 root tabs a few days ago. Maybe I didn't get them as deep in the substrate as I thought. My light is 14W and I run it at about 60% for 8 hours a day on a 10G tank and all my plants are low light. Maybe I'm giving them more light than I think.

[lefty o]

lots of nutrients, and light can cause a bloom that will turn the water green. its not harmful, just unsightly. lots of natural daylight really gets green water going.

[Galabar]

If you aren't using activated carbon or some other form of chemical filtration, your water will have a green or brown tint to your water.  You can test this by using a white bucket for your next water change.

That green or brown tint (at varying levels of opacity) is the price you pay for no chemical filtration. Of course, there are arguments for avoiding chemical filtration that may override the need for clear water.  On the far side of this is reefers, who don't want their PAR decreased by tinted water.  For us freshwater folks, it's more of a matter of aesthetics.  Also, some may be going for a "blackwater" biotope.

  

Edited September 12 by Galabar

[Supermassive]

@Galabar Okay thank you, that makes sense. I'm not using any form of carbon or chemical filtration, just sponges for filtration. I heard carbon removes/destroys liquid fertilizer. I'm also going to put some catappa leaves in the tank so I'm guessing it will turn brown then. I'd prefer it to be brown over green.

So is that slight green color the same thing as actual green water that's full of algae but its just not as much?

 

[AllFishNoBrakes]

I personally don’t believe that carbon is the answer to your questions. You are absolutely correct that carbon will suck up your nutrients/fertilizer. It doesn’t make sense to me to add things to your tank to just have them sucked up by carbon. Also, adding carbon could potentially fix the problem, but then you’ll never really know what the problem was and how to prevent it in the future. Me personally, I would rather understand where the problem came from so I can avoid it in the future, instead of running carbon all the time and not learning. 
 

 I have 14 tanks and don’t run any chemical filtration in any of them. Most of them are crystal clear. Take these tanks for example. 

Both of these tanks have never run any type of chemical filtration for the 3 years they have been running. Is there some detritus/mulm in the water column from time-to-time? For sure. Have I ever pulled water from them in a white bucket and seen any type of green tint? Nope. 
 

If you add Catappa Leaves, you will probably see some tint to the water. 1 leaf probably won’t do a ton, but if you add several you’ll probably see something. I run 2 blackwater tanks and they look like this:

This tank has had tannins since March of this year. While the lights make it look hazy in pictures, in person it’s very clear, just super dark. At this point the water almost looks red under the light. When I do a water change, the water looks like this in a white bucket:

This tank has only had tannins for a couple of weeks, and this tank has Cory’s. I’m slowly adding tannins to this tank as it’s a 29 and therefore pretty tall, but I’ll probably always run into clarity issues thanks to the Cory’s constantly kicking up stuff off the bottom. When I pull water in a white bucket, it looks like this:

I’ve had green water twice, and both times in the same tank. It’s a 6 gallon cube, dirt substrate with a gravel cap, no fertilizer, no filter setup. The first time it happened I don’t have an exact answer as to why it happened. The second time, was because I added a few drops of fertilizer to try to help the red root floaters. I did that once per week over a couple of weeks, upset the balance in that tank, and ended up with a little green water. Both times I’ve had it, I got rid of it by doing a few extra water changes over several weeks, giving it time, and letting the system re-balance. Here’s what that tank looks like right now:

 

You said that you haven’t done a water change in about a month since you filled the tank. I would suggest doing water changes more frequently, especially as your system gets balanced. Balance takes time and consistency, and it sounds like the tank is pretty new. Personally, I would do some extra water changes to get rid of the green water, especially since you only have plants and pest snails. 

My way isn’t always the right way, but it has worked for me. Just my two cents and what I’ve done to get rid of green water when I’ve had it. 

 

Edited September 13 by AllFishNoBrakes

[Galabar]

To my original response, I've sometimes found that water can have a brown or greenish tint when they have organics.  If your water is definitely "green green," carbon (probably) won't help.  It will only remove tint from organics.

To the other respondent, I don't think those tanks have crystal clear water.  You'll see the tint in your white bucket.  Again, it's not a huge deal for freshwater folks, but reefers might have a problem with it.

Without some form of chemical filtration, your water will have a brown tint (to some extent).

Edited September 13 by Galabar

[JettsPapa]

A green tinge to water is likely algae, and is common in new tanks.  It may get darker, or go away.  If it's faint, and doesn't get darker, I wouldn't worry about it.  If it does get darker (and I've seen it dark enough that I couldn't see to the back of a 5 gallon tank), you should be able to fix it with more live plants and limiting light to no more than 6 hours per day.

I will respectfully disagree the the statement that there is always a green or brown tint to freshwater tanks.  I use a white bucket for water changes, and the water that comes out of most of my tanks looks clear enough to drink.

[AllFishNoBrakes]

On 9/13/2023 at 6:54 AM, JettsPapa said:

I will respectfully disagree the the statement that there is always a green or brown tint to freshwater tanks.  I use a white bucket for water changes, and the water that comes out of most of my tanks looks clear enough to drink.

Agreed.

[Supermassive]

@AllFishNoBrakes Very nice tanks, and thanks for all the info. I didn't do any water changes for a month because I thought you didn't need or shouldn't do water changes when the tank is cycling. But now that I think about I really don't know why I thought that. I do plan on doing water changes every 1-2 weeks.

On 9/13/2023 at 8:54 AM, JettsPapa said:

It may get darker, or go away.  If it's faint, and doesn't get darker, I wouldn't worry about it.  If it does get darker (and I've seen it dark enough that I couldn't see to the back of a 5 gallon tank), you should be able to fix it with more live plants and limiting light to no more than 6 hours per day.

@JettsPapa Okay thank you. I will keep an eye on the color. I have quite a few plants already. Ill probably have to adjust the lighting if it gets worse.