My aquarium got cloudy and I don't know why
November 17, 2009 3:58 AM   Subscribe

I have a 20 gallon fishtank with three goldfish and one plecostamus. Everything's been great for over a year until yesterday. There was some water evaporation so I decided to add some plain tap water, a couple of gallons, maybe. I've done this before with no ill consequences. Then I discovered that I had some Aqua Plus left, and poured in about 1/2 cup. It's always worked fine both in this tank and in my pond outside. However, this morning (the "morning after") my tank is completely cloudy! The fish look okay but I just don't understand what's going on. The tap water was completely clear, and Aqua Plus is used to clear up cloudy tanks! What could be going on here?? the fish are still looking good but the cloudy tank looks horrible.
posted by DMelanogaster to Pets & Animals (9 answers total)
I can't find anything online that shows the scale of Aqua Plus, but my water conditioners generally run to one teaspoon per 10 gallons (or 2-3 drops per 2-5 gallons), and I would guess a half cup might be a smidge much for 20 gallons. After a year, you would have had a pretty good balance in your tank, and that much conditioner might have unbalanced the tank and caused a bacterial bloom.

I would do at least 10% water changes daily for a week, and when you draw your tap water to replace what you're taking out, put half a cup of old tank water in the new water and let it sit 15 minutes, rather than putting any more tank conditioner.

It may right itself after 3-4 days, but I'd double-check the recommended dosage and go with the water changes if you over-treated.
posted by Lyn Never at 4:16 AM on November 17, 2009

I'm thinking it's a reaction to that half-a-cup of Aqua Plus as well. I usually use a capful in my 30 gallon.
posted by Richat at 5:08 AM on November 17, 2009

2nding Lyn Never. The cloudyness (milky) is very likely a bacterial bloom. My guess is that the Aqua Plus contains a non-harmful version of Ammonia which is meant to jump-start the Nitrogen Cycle with non-toxic fuel. If so, it will clear up in a few days as the bacteria settle into your filter media, rocks, and other surfaces in the tank. Outdoor ponds are going to be in the hundreds of gallons range, so a cup of conditioner makes sense. The correct dose for a 20 gal is more likely to be a thimble full or less. Anyway, the bacteria aren't going to harm the fish. Just do water changes and keep the water circulating with a filter or airstone.
posted by cowbellemoo at 6:48 AM on November 17, 2009

I used to use a Magnum canister filter, the kind that hang on the side of the tank, for temp clean-up jobs like this. Fill it with charcoal and let it run for a few days.
posted by Cool Papa Bell at 6:50 AM on November 17, 2009

Speaking from my pet store experience, it sounds like it's a bacterial bloom. One thing you can do in the future to keep this from happening is to change a gallon or two of water every week, instead of waiting for evaporation. Depending on what size bottle of aqua plus you have, the correct dose is somewhere close to a capful per 10 gallons. If you're on the scale of a gallon or two gallons, a few drops is fine.
posted by d13t_p3ps1 at 7:05 AM on November 17, 2009

BTW, if you are going to use tap water for your aquarium; it's an excellent idea to let it sit overnight in a holding container such as a clean bucket with an open top -- so that any chlorine content can evaporate. (Tip learnt from a hard-core fish collector.)
posted by Jade Dragon at 9:57 AM on November 17, 2009

What kind of filter does the tank have? did you drain out any of the old water, or just replace what had evaporated? If you're just adding more water and not removing old water before replacing it, you're going to have mineral build up. You've probably just hit a chemical/mineral balance that's feeding a baterial bloom that will go away in a week or so. Feed the fish a bit less, do a few more partial water changes and this will go away sooner. I think the water conditioner is incidental to the cloudiness.
posted by jrishel at 10:51 AM on November 17, 2009

My god I love you people.

Sorry if that was too mushy.

I will do some gradual water changes and see what happens. That was very ridiculous taht I poured all that conditioner in there!

posted by DMelanogaster at 3:52 PM on November 17, 2009

Well my tank cleared up all by itself. I didn't even change any water. Thank you again, I'm so relieved.
posted by DMelanogaster at 3:53 PM on November 23, 2009

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