Cloudy murky green water

[mrsjoannh13]

I have a pretty well established 20 gallon planted tank.  It's been up and running for about a year and doing great.  Over the past couple of weeks, very soon after my water changes, the water turns cloudy and has a greenish tint to it.  I haven't changed anything in terms of lighting, plants, fertilizers, fish load, etc.   So I'm at a loss as to what could be causing the murky green tint.   I'm assuming it's some sort of algae bloom?   Is this something that happens in established tanks?   Any other ideas?   Thanks in advance.

[lefty o]

usually green water comes from lots of nutrients, and being in natural daylight. is it near a window where it gets direct sunlight?

[mrsjoannh13]

On 10/8/2021 at 6:16 PM, lefty o said:

usually green water comes from lots of nutrients, and being in natural daylight. is it near a window where it gets direct sunlight?

I haven't changed the nutrients.  Using easy green, easy carbon and easy iron per the label instructions.

It is in a room with a window but I've always kept the shades open a bit during the day and closed them in the afternoon.  I was wondering if, with the change in seasons, the sun is in a different position and maybe there is a bit more light coming through?   Over the past couple of days I've been keeping the blinds in there closed to see if that has an impact.  

Appreciate the thoughts and ideas!

[lefty o]

it could very well be related to the sun angle change.

[Guppysnail]

I have my tanks positioned about the room so they each get a bit of natural sun all year. I started with one green killing machine uv that I would move from tank to tank throughout the year as the seasons changed. Whichever tank got the most direct sun the longest would get a green tint so I would move the uv to that tank to avoid green water. 
Welcome to the forum. 

Edited October 9, 2021 by Guppysnail

[Torrey]

On 10/8/2021 at 5:18 PM, mrsjoannh13 said:

I haven't changed the nutrients.  Using easy green, easy carbon and easy iron per the label instructions.

It is in a room with a window but I've always kept the shades open a bit during the day and closed them in the afternoon.  I was wondering if, with the change in seasons, the sun is in a different position and maybe there is a bit more light coming through?   Over the past couple of days I've been keeping the blinds in there closed to see if that has an impact.  

Appreciate the thoughts and ideas!

Have you tested your tap water, and do you know what the parameters were for your tap water before,  when the water changes didn't make your tank turn green and murky?

If everything else is the same, look at the variable that consistently triggers the change in water: the water used for the water change.

[mrsjoannh13]

Yes, I test on a regular basis with an API test kit.  No parameters have changed that would explain the murky water.   I'm at a loss other than the potential increase in light from the window.  I'm going to keep the shades closed and see if that makes an impact.  If not I guess the UV sterilizer will be the next step.

Thanks again for all the thoughts and responses.  

[Torrey]

On 10/9/2021 at 10:53 AM, mrsjoannh13 said:

Yes, I test on a regular basis with an API test kit.  No parameters have changed that would explain the murky water.   I'm at a loss other than the potential increase in light from the window.  I'm going to keep the shades closed and see if that makes an impact.  If not I guess the UV sterilizer will be the next step.

Thanks again for all the thoughts and responses.  

So I guess what I am asking (awkwardly) is what are the parameters of the water you are putting into the tank?

[mrsjoannh13]

On 10/9/2021 at 12:18 PM, Torrey said:

So I guess what I am asking (awkwardly) is what are the parameters of the water you are putting into the tank?

Sure thing!  So everything's been stable since I set the tank up about 10 months ago....

0 ammonia and nitrite.  Nitrates are about 20 - 30 before a water change and about 10 after a change.  GH is 5-6 (I use Equilibrium to keep it at this level - my tap is 0).  KH is 6.  pH 7.6 - 7.8.  

[eatyourpeas]

Trying to identify the source of your nutrient imbalance is always good, so as suggested, start with the light period and intensity. I do get more diatoms in Autumn/Winter due to the sun being lower and hitting the tanks directly.

[CalmedByFish]

When I was getting green water, I tried the usual advice about light and nutrients, then someone here suggested increasing biological filtration. It was a 20 gallon, using a HOB and intake sponge. I added a medium-sized sponge filter, and liquid bacteria. That approximately doubled the amount of bio filtration. It was something like 2-4 weeks later that I woke up to crystal clear water. 

I'm not sure if that will apply to an established tank, but since the green water is happening repeatedly, it might.

[Torrey]

On 10/9/2021 at 3:06 PM, CalmedByFish said:

When I was getting green water, I tried the usual advice about light and nutrients, then someone here suggested increasing biological filtration. It was a 20 gallon, using a HOB and intake sponge. I added a medium-sized sponge filter, and liquid bacteria. That approximately doubled the amount of bio filtration. It was something like 2-4 weeks later that I woke up to crystal clear water. 

I'm not sure if that will apply to an established tank, but since the green water is happening repeatedly, it might.

I have established tanks that will still get cloudy if I try to take too many pictures in a week [I learned new tricks, I am testing the photography hacks and *might* be overfeeding 😅].

Dose with beneficial bacteria 2 days in a row, and the water is clear when I wake up on day 3.

 

Excellent point!

Also, I forget that infusoria cultures will clean up green water pretty quickly, and provide a healthy fry food.