Green water problem in axie tank.

[Manifest]

Hey all, I have a nicely cycled tank with a healthy green algae bloom and I was just wondering how I would go about cleaning up the bloom? I can't think for the life of me what we might have done to trigger it. We were getting spots of brown algae here and there on the plants and tank wall so were managing that by scraping the glass every few days and doing small water changes, and then all of a sudden, overnight, we went from clear to cloudy bright green water. The tank gets no direct sunlight, and we did have the aquarium light on 4 - 6 hours a day. We bought a new purigen sachet, tested the water and everything was absolutely fine, 0ppm of nitrite and ammonia and 5 ppm of nitrate, our plants and axie are healthy, but we'd really like to have clear water again. Our goldfish tank, which is right next to the window and has a light on for about 8 hours a day, doesn't have a green water problem.

Anyone had experience cleaning this up? We've been keeping the light off and doing the small water changes but nothing so far. Next step will be light deprivation but I'm worried this will kill the plants.

We have an external canister filter with a chiller attached so the tank is constant at 18 degrees Celsius.

 

[Mac Myers]

I've had Freshwater Aquariums for most of my life.
That said for a long time I didn't understand anything about the chemistry of a tank or what caused problems.... mostly because I was lucky enough to have no problems.
The things that cause algae blooms, ( overcrowding and waste, light, excessive nutrients, poor water quality) can be difficult to ...well... accept. But that is pretty much all that there is to it. Sometimes you think all is well..... but it isn't. You have a problem with one of these things.
From your description of the tank and the problem it doesn't sound like you do.... and it sounds like you know what you are talking about.
So I guess my answer is that I'm not sure. It has to be one of these things. Your live plants apparently cannot handle the excess nutrients in the water. Algae can be removed by a ridiculously expensive diatomaceous earth filter, daily water changes etc.... but you have to eliminate the root problem... one of the above problems.... or you never win. You can't use chemicals to kill it. :happy: I'm a little foggy today so hopefully this little ramble makes some sense to you.

 

[Manifest]

Thanks for your response Mac, it made enough sense to me!

Thinking aloud here..
I don't think it's overcrowding since we have one axolotl in a 120L tank, she's got plenty of space, we poop scoop whenever we see the poops and vacuum/water change once every week to week and a half so I don't think it's waste, she gets a single block of worms a day, sometimes once every 2 days, and there is never any leftover, little piggy eats them all in very short order and spends the next few hours hunting down the strays so it's not that... hmm

Maybe we need more plants in there or something? I've been thinking about adding another couple of plants anyway. The only thing I can think of is we had a blue light bulb on for a while and didn't have any algae issue, but we switched back to the regular white light a couple of weeks ago so that may have triggered it. Since we noticed the bloom, we've mostly left the light off so it's only getting very dim ambient light from the room.

Anyway, we've really spent a lot of money on this tank and aren't about to go buying an earth filter. I've read some advice online about wrapping the tank in a towel for a few days to kill the algae but that this will also kill the plants. I can't imagine the axie would mind being in the dark for a few days, given how light sensitive they are. I might move my plants into the goldfish tank and give that a go. Will post an update if I get a result!

 

[Abrahm]

Well, it definitely sounds like you're on the right track. Figuring out the root cause will give you the best results.

How are your plants doing? Any dead leaves in the tank? It's possible that there might be some decaying plant material that is feeding the algae bloom.

You say you feed blocks of worms, are these frozen blood worms? If you drop the whole cube into the tank you're also dropping in a lot of (formerly) frozen water rich in biological molecules like proteins. If this is the case you can try thawing your bloodworms before hand and then straining the water away with cheesecloth or a plankton net (the white nets often sold at petstores.) It may be that additional biological load that's tipping the balance.

I also just noticed that you feed everyday. I would scale the feedings back to at least every other day. Possibly every third day depending upon temperature. You may be collecting all the poop, but I believe that axies also excrete some of their waste through the gills as ammonia, which is a colorless liquid.

For now, I would follow my above advice and start doing water changes two to three times a week until you get the algae under control and then go back to a maintenance schedule of every week.

 

[jclee]

Do you know exactly what kind of a lightbulb it is? And how strong? It could simply be that there's too much light -- from the bulb, rather than the sun -- so that even though you've shortened the time the light's on, it's causing/enhancing the algae.

 

[Mac Myers]

That sounds like a winner to me. For plants I pretty much use only Java Moss and Pothos vines. Hard to kill either. Actually I don't think Java Moss can be killed unless you drive a stake through it's heart. And if a Pothos vine gets too ratty then I just swap it out for another and let the beat up one recoup hanging out of a jar.

Let us know. :happy:

 

[Jennewt]

My advice is to be patient, it takes time to get rid of green water. Rest assured that the green water doesn't hurt the axies at all. If you keep doing the right things, it will eventually clear up.

Have you tested the nitrate level? This will give you some idea of whether you need to increase the amounts of your partial water changes, and by how much.

My other suggestion is to add some duckweed to the tank. It's very good at sucking up extra nutrients from the water and will compete with the green water. For reasons that are complicated to explain, duckweed competes for nutrients much more effectively than your other water plants do.

 

[Manifest]

Update: we bought some more plants, and have done a couple of things to clear up the green water and seem to be making headway, we can actually see the other side of the tank now anyway

I covered much of the external filter tubing (clear plastic that we recently replaced because the original stuff was all crudded up with algae of both green and brown variety) with aluminium foil so it doesn't get any light at all. This seems to have stalled new algae growth in the tubing. We've been mostly keeping the light off, except for the last couple of days just turning it on for a couple of hours during daylight so the plants themselves won't die, and we've been doing a 20% (2 10L buckets) water change every day for the past few days and so far, so good, the water is clearing up nicely. Still a little green but I think if we keep this routine up for a few days longer it should be fine. We've also been feeding her once every 2 days and it breaks my heart to see her begging in the food corner for more worms on the off day!

Duckweed is a good idea, I'll look into adding some to the tank. The only thing that would concern me is duckweed's tendancy to cover the surface very quickly and getting light in to the other plants.

I'm a little worried about my Axie, she's still active and eating fine, but she had a major shed last time we disturbed the tank (cleaning the filter and replacing the tubes - we didn't crash the tank tho, all the tests were good) so she obviously found the process stressful, but some of her gill filaments seem to have become a lot shorter in the last couple of weeks, like someone took a flame to a human hair, you know how it shrivels up and gets a little stubby end? Looks a little like that. I'll have to keep a closer eye on her and hope she recovers. Silly stressy thing!

Oh to answer some other questions, the plants look really, really healthy! Roots going in all directions, new leaves popping up everywhere. I think there may even be a flower coming in on one of them. So excess nutrients is probably a big factor here. Adding a couple of new plants has certainly made a difference. Interestingly, the brown algae we did have all over the glass, plants, pot, wood, etc is nowhere to be seen either

We also seem to have a lot of copepods, which I think is probably a good thing, I see them clustering around any worm fragments that are left over from feeding time.