Algae Bloom

Question
QUESTION: My 55 gallon tank has had an algae bloom continuously for a month now.  I am not overfeeding, I am not overstocked, my ammonia level nitrate and nitrite levels are all zero and my filter is more than needed for the tank size.

That said, I have tried algae controllers, no light at all, huge water changes... etc...

I cannot control it at all.

Yesterday one of my bala sharks slammed into the side of the tank so hard he died instantly.

Today, another one has cloudy eyes.  I removed him from the tank and although he is TOO big for my 20 gallon, I feel his problem is oxygen and needs the healthier environment.  He looks blind and like he is gasping.

What on EARTH should I do?  I only have 1 bala, 2 cory cats and 1 blue guarmi in the tank.  

I am at a loss here...and losing my bala yesterday was horrible... to lose the others would be horrible.

Any other suggestions?

Ma

ANSWER: Hi Maryann,

Algae thrives when excess nutrients and light are present within it's environment. However, your tests are coming back perfect and you've starved it of a light source. So, basically, some other source is feeding it.

What you need to do here is check the levels of phosphate that are present in the Aquarium water. Phosphate comes from three sources, tap water, fish food and carbon. In the City water companies often add phosphate to the water to protect its pipes against corrosion. In suburbs and the country it is often present through fertilisers being dumped in the water.

You need to keep your phosphate levels as low as possible. To achieve this remove any uneaten food from the Aquarium using a gravel vac. To remove present phosphate you can use one of plenty of phosphate removers on the market. Alternatively, you could start using Reverse Osmosis (RO) water for regular water changes. This will drop the level of unnatural elements in the water but make sure you have minerals added to the water at your local fish store.

Choosing a suitable filter media can also have a affect on phosphate levels. Poly filters will remove phosphate and heavy metals. It will indicate any other problems in the tank by changing colour.
Carbon phosphate Remover will also remove phosphate from the tank in large quantities. The carbon will keep your water crystal clear and make the algae disappear.

If any of the above doesn't work then you may have to shell out on a UV Steriliser. It's a pretty expensive bit of kit and is designed for ponds however it will neutralise algae particles and remove harmful organisms lurking in the water.

Also install an air line and get the water surface visible churning for optimum oxygen exchange. Your fish are, technically, too big but if your over-filtering then you should be okay.

Good luck!

Tom

---------- FOLLOW-UP ----------

QUESTION: Hi Tom,

THANK YOU for being so prompt.  I changed out 20% of the water today w/RO water from the fish store and also purchased airpump 7500 (for a 100 gallon tank.)  Also have not turned the lights on and the fish have not been  feed in 5 days.

Vacummed the gravel a BIT too.  Only half the tank though since I did a filter change not too long ago.

I also took out the driftwood today. I just don't trust it.

Tank appears a BIT less green.  

I have no idea how to test phosphates.  Could you give me an idea?

You also mentioned carbon.  I buy the activated carbon and change it out every two months.  Should I change it out again?

Last buy not least.... the bala with the cloudy eyes.  One looks red at the bottom, like it is bleeding.  His breathing seems a bit better.

What are the chances of recovery after oxygen deprivation?

Many thanks,
Maryann

Answer
Hi Maryann,

It might be worth placing phosphate remover in your filter as the active media. Although carbon will keep your water clear it will present a problem with what I'm about to suggest.

Oxygen deprivation is displayed by listlessness, blotchy colouration and increased respiration rate. If your Bala has an eye problem then it could either be cloudy eye or the onset of pop-eye. To fix this you may want to dose the tank with Melafix (1tsp/ 38L). However, Melafix and Carbon don't really like each other so you'll need to remove the filter media before treating the tank. If treated correctly then recovery should be pretty successful. Many goldfish suffer from oxygen deprivation even in fish shops. However when placed in suitable conditions they make a full recovery.

I'm guessing your tank is a modern one. Modern day tanks have a tendency to let the dissolved oxygen fall below satisfactory levels. Kits to test oxygen are often expensive and even the cheap ones are even worth looking at. Basically your saturated oxygen needs to be 8mg/L and never below 5.5mg/L. Rather than rushing out to buy one move your filter up so the surface water is visibly churning. Moving water is far better oxygenated than still water. Try placing a venturi line on your filter as well, so oxygen is forced into the return valve.

You could try dropping the temperature of the tank a little bit. I'm guessing at the moment it is around 24C (75F). Try dropping it gradually to 74F. It doesn't sound a lot but cooler water is full of saturated oxygen.

Alternatively we could drop the nitrates to zero and keep them there. Without nitrate Algae will not grow no matter how much phosphate is present in the water. All this means is very regualr testing, water changes and filter maintenance. Alternatively plant the tank to the hilt with live plants, feed and give light sparingly. This way you will starve the algae of the necessary nutrients that it needs to grow.

Tom