A club for owners of Parrot Cichlids

For about 4 months, I had been fighting a war against algae in our biggest tank, home to our oscar "Idli." Idli not a Parrot Cichlid but this will be interesting for anyone dealing with greenwater algae problems.

Contents

• 1 Algae's Four Foodgroups
• 2 Hunt down and remove excess nutrients from the water
• 3 Wet Dry filters
• 4 Dissolved nitrates - the hidden culprit!
• 5 The fix

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Algae's Four Foodgroups
Algae needs 4 items in sufficient quantities to grow: Light, Air, Food, and Water.
Water and Air you can't do much about.
Food - and by this I mean what ALGAE considers to be food, which is darn near anything - and Light - can be adjusted, but tropical fish also need light to be happy, so the best first step is to check if the algae have a hidden food supply.

Hunt down and remove excess nutrients from the water
If you don't clean your tank often, start with that. Gravel needs to be thoroughly suctioned regularly, ornaments need to be lifted up and vacuumed under, just like you'd do your rugs. Parrot cichlids are not good at cleaning up after themselves, so things get pretty gross fast.
In the past I've had greenwater algae problems in the parrots' tank, and the source of the problem has ALWAYS proved to be a cache of old food or a filter sponge that has collected so much crud that it becomes an algae farm. In all cases, we stopped the algae in its tracks by cleaning up the source - the prefilter or the interior sponge, and keeping it clean. After that, the water remained clear no matter the light levels.
Last year we purchased two wet/dry filters, one for the oscar's 90 gallon tank, and the other for the goldfish's 40 gallon. The reason for having it on the goldfish is: they are in a tank that is a little small for them, so we put an overpowered filter on it. Both filters performed fine, and everyone was happy.

Wet Dry filters
If you don't know what a wet/dry filter is, basically it is a tall plastic box, or tower, with shelf-like layers of filter material and one big chamber filled with bioballs on the bottom. Water pours in through filter material at the top, gets spread out by a plastic screen/shelf, and drips over bio-balls which provide the surface for bacteria to grow and turn ammonia into nitrates.
The tower sits in a small aquarium under the tank, in about 5 inches of water. The bioballs are above the surface of the water, and always have air so the aerobic bacteria can breathe. It turns out that those bioballs are pretty darn efficient at their little nitrate production process.
About two months after we moved, we also got a bigger tank for our oscar. The new tank is a 120 gallon with a dual overflow system that feeds into the top of the wet/dry tower. Our friend the Fsh Doctor set it up, very nicely, right in front of a huge bank of windows, which was the only spot we had for it. It is all powered by two big Rio pumps, which kept the water pressure very high going into the top of the filter. It was basically a firehose, pouring through that wet/dry tower.
So, the "algae variables" changed. For one thing there was a lot more light! The only place we could put our tanks was in the living room in front of six bright windows. We realized this would cause problems, but there was nothing we could do about the light. I am not going to live in the dark because Idli can't keep his tank clean! I realize that many aquarists WOULD, but I am not one of them!
The amount of water going through the filter had also doubled, and the tank was bigger.
At first things were fine. Then after a month or so, we started to get greenwater problems. We did water changes, frequent cleanings, I added prefilters, all to no avail. I was really puzzled because the 90 gallon had been in the same spot with the same wet/dry filter, and no algae. Also, the goldfish tank is right next to the window, and it gets some algae, but not nearly as much.
I bought 2 Magnum filters, the 350 and the 250, and put the 350 on the oscar tank, the 250 on the goldfish. The goldfish cleared up and remained sparkling clear. They had never been so clear in their lives, I think. I clean the micron filter about once a week.
The oscar tank cleared up for about a week, then slowly got cloudy again, no matter how many times I cleaned the micron filter, and despite 99.9% water changes, and everything we could think of.
Then after about another month, the algae exploded! It was growing so fast, that the tank remained GREEN no matter what I did.
I was totally fed up. I was spending more time on that tank than on my household chores. It was an eyesore. I wasn't too worried about the oscar getting suffocated at night (they say algae can do that) because he had about the same level of aeration as the Hoover Dam, but I had definitely had enough of that green stuff.
Then, I read a post somewhere that talked about wet/dry filters losing favor with some marine aquarists because they are such efficient biological filters that they become nitrate factories.

Dissolved nitrates - the hidden culprit!
A little light went on in my head. THERE was the cache of algae food! The filter itself. I saw two possibilities: one was that the water pressure going into the filter is so high that no matter how much filter material I put in the top shelf, bits of crud get through and just circulate constantly. The other was that the crud WAS getting filtered out but the bacteria on the bioballs were pouring out nitrates at an accelerated rate because so much water was pouring over them so fast. No matter which was the real reason, both possibilities could be solved by cutting off one of the Rio pumps.

The fix
So, 2 weeks ago I repeated my ritual: I drained Idli's tank down to his ankles, (he had to lay on his side for a few minutes to stay under) then kept flushing it with clean water until the water was crystal clear. I drained the overflow chambers, and the sump. Then I filled the tank with fresh water, and cleaned the micron cartridge and all the filter material in the wet/dry.
But this time, I made the big change - I only turned on one Rio pump, and the Magnum filter. So the water is being circulated at about half the rate it used to be, plus a trip through the Magnum to remove any algae.
It totally worked! He has remained clear ever since. The Magnum filter is off to the side of his tank where I can keep an eye on it, since the canister is transparent and you can see the state of the filter inside it.