Why is my tank a giant green cloud?

[CJ29DJ]

As the thread subject suggests, my tank is one big, green, cloudy mess. How do I solve this problem? I set up and cycled the tank about 2 months ago. I had no initial problems whatsoever with algae or any sort of water quality issues. Lately, though, the tank turns into a greenish cloud less than a week after I do a water change. I'm following all of the rules an aquarist must follow, it seems. I'm not over feeding nor overstocking, I'm not messing with biological bacteria, am performing weekly 20% water changes, checking water parameters each week. I have tried to tame it by adding some Seachem Purigen to my list of filter media - it seems to have no effect. What could I be omitting or doing wrong to cause this? What can I do to stop this and prevent this from happening again? What exactly is happening?

My 55g tank includes 8 Cardinal Tetras, 5 Oto cats, 2 glass shrimp, and 3 cobra guppies. I haven't wanted to add anything else because the water has been acting like this recently.

For hardware, I have two AquaClear 50 power filters (one is currently broke though - motor needs replaced), a Hydor Koralia Evolution 550 pump, Fluval M 200W heater, and a Beamswork 48" LED light (which is on from 10 am - 8 pm).

Thanks to whomever may help; I'll greatly appreciate it.

 

[Newkeeperotis]

Light is on to long for a start need to shut the time down to 5hrs a day 6 at the most this is probably the sole cause the only other thing to say is you may want to do 50% water changes per week that's what I do on my 30 gal hope this helps

 

[Rivercats]

Put some tank water in a white cup. If it is tinted green then you have an algae bloom. No amount of WC's or running lights will help with it. You have two choices. First you can do a 3 day black out. You have to completely cover the sides, top, and bottom of the tank so absolutely no light gets in. No peeking either or it breaks the light cycle. On day 4 open the tank to light and do a 60% WC. Only run lights for 6 hours a day and feed lightly. This "may" work. The algae bloom could come back if any of the free floating algae wasn't killed off.

Option 2 which is the best IMO is get a small UV sterilizer like this one... Green Killing Machine Internal UV Sterilizer with Power Head at PETCO. This will kill all the free floating algae in a very short amount of time, usually 24-48 hours depending how bad the bloom is. Many people on the forum use it and have gotten excellent results.

Regardless of which method you use you still need to lower your light time. I also suggest doing a 50% WC weekly.

 

[CJ29DJ]

Alright. Thanks, sounds like great advice. I've noticed that it'll be cloudy with an algae bloom for a week or so and then it will clear up all of the sudden and there will be small clusters of brownish algae on my artificial plants and that's about it. What do you think that suggests? Is that normal?

 

[Rivercats]

An algae bloom won't clear up. Do the water in a white cup test. If the water has a green tint it is an algae bloom. If it's an algae bloom it's clearer when you do a WC as your removing algae but it will always come back. If the water in the cup isn't green tinted then your having a bacterial bloom which is totally different.

 

[Fishfur]

If you find it's not algae, you may find useful info here. A bit technical, but very good info we should all know.

Heterotrophic Bacteria and Their Practical Application in a Freshwater Aquarium

Bacterial blooms are often the result of overfeeding, but there are other reasons too.
Do that white cup test.. it's not green, it's not algae.

The brown stuff is likely diatoms, which are common in new tanks, but usually self limiting. They use up silicates and then tend to pretty much disappear. But almost all snails love the stuff, so you can try snails to eat up what there is.

 

[Dallascowboys16]

I own the green killing machine uv sterilizer and it really helps to put a polish on the water of my tank. Should fix the algae problem but we really need to find the source of the problem, isn you tank planted and do you use any fertilizers? With these answers we could help figure out what is causing the green water.

 

[CJ29DJ]

Thanks, guys, really enjoying all the helpful feedback. I will try the white cup test. Would it also work with a clear glass cup? I have white freshwater sand substrate with no live plants. The only things living in my tank are fish/inverts.

 

[Rivercats]

I don't know if a clear cup would work but I guess you could try and hold the cup against something white. Or you can use a bowl or anything white to put the water in. It's just so easy to tell if there is even a slight tint of green in the water when you put it in a white container of some kind.

 

[CJ29DJ]

Performed the cup test - appears to be an algae bloom. Looks like I'll get a UV sterilizer; will this solve my problem for the most part?

 

[CJ29DJ]

Also, which UV sterilizer brands do you guys trust the most?

 

[Fishfur]

Or you could see if you can get some live daphnia. They'd eat it in no time, then be fish food your fish will love. Filter feeding shrimp would eat it too.. Bamboo shrimp, but then you have Bamboo shrimp to keep, or maybe take back to the store.

 

[GodFan]

If you are gonna spend the mula on a uv then I would spend just a bit more and get a canister filter with a uv built in. Aquatop makes them I think.

 

[Rivercats]

I don't suggest the canister with the UV as I've read a lot of people are not happy with it. Many people on the forum use this and have had very good results... Green Killing Machine Internal UV Sterilizer with Power Head at PETCO. It will kill all the free floating algae in the tank usually within 24-48 hours. Once the tank is crystal clear all you need to do is a 50-60% WC to remove all the dead algae.

 

[Jerinanyon]

I had the same problem. Make sure the water you're topping your tank off with is Ro/DI. Do a few water changes and it should go away.

 

[GodFan]

I have used the green killing machine and can tell you it works wonders.

 

[CJ29DJ]

Alright. Well good, I will get the green killing machine then, it seems to be what I need. Thanks for the help, guys

 

[Jerinanyon]

CJ what do you feed your fish? If you're using pellets, it will turn your tank green if your fish don't eat most of them

 

[CJ29DJ]

I feed them Spectrum small fish pellets and treat them to small doses of bloodworms once per week. I usually feed them a pinch or two twice a day and watch how much they eat, which is always all of it. However, it's been hard to see how much they eat lately with the green cloud and all.

 

[Rivercats]

I had the same problem. Make sure the water you're topping your tank off with is Ro/DI. Do a few water changes and it should go away.

A true green water algae bloom will not go away with just WC's. All the free floating algae cells have to be killed off or it will just keep coming back.