Green water - How can I get rid of it??!!!
 

I have a 70 gallon freshwater tank. It was great the first 5 months with just fish, no plants in it. Somehow I got an algae bloom in my tank and now my tank has been green ever since. The fish have all been fine, but its just hard to see them. Here's what I have done to it and my tank parameters:

• Water quality: Ammonia, Nitrite, Nitrate, PH, Alkalinity, Hardness, Chlorine, all zero or in normal zone
• Tested for Phosphates: 10.0+ obviously it was off the scale
• My tap water had 1.0 phosphates in it already
• Added a few plants to help with the phosphates - no change
• Aeration: 2 bubblers which I turned up to increase air in the tank - no change
• Filters: 2 Outside filters and one Under gravel filter tube with power head
• Temp: 80
• Water changes: 50%-66% weekly! but the green comes back
• I have two 20 gallon tanks using the same water and they are not green at all
• Chemicals used: Algae fix (didn't help), Microbial Algae clean (didn't help), Algae Destroyer (didn't help),
• What did seem to help was the combination of: Phosguard or Phospure in one bag, while I put a Poly filter in one of my filters. This cleared the tank of phosphates in a day, left a white cloudiness, but then after a week, I assume the poly filter was full, and the green started coming back.

I bought a bunch of poly filters, but by themselves, they don't work. Its way too expensive to buy phospure, phosguard, and polyfilters to clean the tank and/or make weekly tank changes.

There must be a way to clear the tank so I can have normal clear water like my other tanks and only make monthly water changes.

I am about to drain the tank and start over!

Help!!!

Additional info....

I have minimal or no algae on the glass or my rocks, etc. Its just in the water.

Also, I bought new light bulbs, one 50/50 blue/white and the other a regular white aquarium bulb, not the cheap home depot bulbs.

Also, I only keep the light on 10 hours out of the day and there's no direct sunlight into the tank.

I've honestly never had this issue so I don't know what causes it or how to get rid of it...

With that said if you don't have live plants and want to risk it you can buy "Clear Water" from jungle ... i believe...

Green water is caused when green unicellular algae reproduce so rapidly the water turns green. This happens because of high light and high nutrients.

I would be interested in the exact number for nitrates; I expect it is very high, certainly not "normal" or this would not occur.

The light you have is also contributing to the problem; the "blue/white" I assume is actinic or similar, a type of light that is intended for corals and reef tanks because it simulates the colour of sunlight that penetrates to those depths. It is not a good choice for freshwater, as all algae find it favourable, and plants do not do well under it.

Having a well-planted tank can prevent green water, provided the light is balanced with the nutrients such that the plants can use both completely. But it takes more than a few plants. Without plants, there is nothing to use those nutrients except algae.

A caution on using chemicals to handle algae: don't. These will not work on green water, but even with other types of true algae, they are very dangerous to the fish and not worth the risk. There is always a reason for algae, and finding it and rectifying it is the only good course.

As for getting rid of it, obviously reduce the nutrients and the light. Even if you did reduce this with major water changes, it will only return if the cause is not rectified. What is the fish load in this tank? And what is the feeding schedule? And normally how often is a partial water change carried out, and with how much volume? Knowing this information will help us advise on the solution.

Byron.

Byron is absolutly right about the lights.I used to think brighter was better but I took his advise(and others on the forum) and switched to the "cheap Home Depot" bulbs-6700k and my tank is clear with no algea problems and the coloration of the fish is much better.

I have two 4ft bulbs over the tank, one is the 50/50 actinic/white bulb about 8000k and the other was a standard Wallmart Aquarium bulb, low intensity. I will take the actinic light off the tank immediately.

I will also stop using any chemicals.

I only have a couple plants in the tank. The fish end up eating most of the plants unless they are broad leafed.

Here what my last few tests of water have shown iver the last 60 days: Nitrate 20-40, PH at 7.2, Alkalinity 0-50, Nitrites 0, Temp 80 degrees, Ammonia .1, Phosphates obviously high

I feed minimally. It seems the fish are always hungry. Hardly any food hits the ground and my catfish or algae eater picks that up, if at all. The silver dollars and bala shark are so big, they eat a lot.

70 gallon tank
Fish:
Two 6 inch Silver Dollars
One 7 inch Bala shark
Two 4 inch angels
Two 2 inch white tetras
Three 1 inch silver tipped tetras
One betta
Two 2.5 inch blue gouramis
One 2 inch algae eater
One 2 inch Pleco
One fiddler crab
One 2 inch catfish

Water changes have been weekly lately to keep the tank clearer, but it keeps coming back. I have been changing 66% of the 70 gallon water.

Feeding happens twice a day.

What reading do you get for nitrates in your tap water? 20-40 ppm seems pretty high for a tank that gets a 2/3 water change every week.

I was reading on other threads, apparently some aquarist will leave the light off some days to simulate cloudy or rainy days. This could help on reducing the algae growth. But i do agree with Byron, the light should be replace, and the chemical not used unless it is the last resource.

Does anyone think UG filter could be contributing to the problem?:dunno: