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Cloudy Water After Water Changes

98K views 14 replies 6 participants last post by  Death_by_Dinosaurs 
#1 · (Edited by Moderator)
I have a question I'm hoping someone can help with. I've had my 29-gallon tank up and running for 6 months now. I'm not new to fishkeeping. I've run into a problem I've never had before. My tank was properly cycled (to a "T") and has done extremely well since the cycle was done.

My water has always been crystal clear and the levels have stayed darn-near perfect (and still are). My fish are healthy and happy. I have not lost a fish for any reason in over a year.

With that said, here is my problem. I did my weekly water change (25%) and added a new filter cartridge (the new cartridge was put in the day after the water change as per usual). Before someone asks, no I do not change the filter every week, just once a month. This is the first time my water has become cloudy after this process. In all my years, I've never had this happen. It looks like someone poured a half-gallon of milk into the tank. Very odd. My fish are all acting normal with their usual disposition and respiration and my levels all continue to test in the normal range. It's just the water is cloudy (and getting worse).

Has anyone run into a problem like this? I treat my water a day before putting it into the tank and allow it to vent and warm to room temp. It's been my magic trick, so that can't be it. I've changed the filter cartridge this way for years, so that can't be it. This tank is 6 months old, so it's not a cycling issue (but perhaps a re-cycle issue). What could it be?

The only thing I can think of is the algae wafers. I just started adding them for my Cory Cats to enjoy. Could they have sparked an overabundance of algae in my tank? I'm stumped. Any ideas? Has this happened to anyone else here? How can I try to solve this mystery?


  • 29-gallon tank

  • 2 filters: Tetra EX45 and a Top Fin 30

  • 12 fish in the tank (Platy, Molly, Cory)

  • Water temp is 78-80 degrees and remains consistent

  • Aquarium established 6 months ago

  • Cycled properly

  • 25% water change weekly

  • Alternate filter changes monthly

  • Level are near-perfect and consistent
Water is cloudy. Any ideas or thoughts? Help is appreciated.
 
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#2 ·
Cloudy water after a water change is fairly common, although like you, I've rarely had it happen to me. Setting aside the obvious of stirring up the substrate, the cloudiness is often the simple result of dissolved organic compounds in the water. A bacteria bloom to compensate results in the cloudy water. It should clear up in the next day or two.
 
#3 ·
Thank you, sir. It freaked me out a bit because, as I said, it's never happened before in all my years (aside from the initial bacterial bloom during a cycle).

My wife wanted to add a water clarifier, but I'm against adding any chemicals to my tanks that are unnecessary. I refuse to do that. I'll just play the waiting game and have my quarantine tank on the ready, just in case.
 
#4 ·
Good for you - chemical clarifier's work by binding small particulate matter together making it easier for filter media to trap. I have heard they can be very hard on fish, impeding oxygen xfer in the gills.

The fish should be fine as they are not negatively affected by cloudy water, it's much more an aesthetics issue.
 
#5 ·
One more thought. I don't know what you have for a filter but many come with open cell foam or other somewhat open pad material for mechanical filtration. I found that in my Aquaclear 70 filter that tiny particles would just pass right on through (or detritus would break down into small particles that went through).
I fixed this by adding a final layer of polyester filter fiber to polish the water just before it returns to the tank. Oh and don't pay extra at the LFS - you can get a good sized bag of polyester fiber at wallymart for $4 (used to stuff pillows). I realize that filter fiber or floss is old school...but some things stand the test of time ;-)
 
#6 ·
I concur with AD that this is most likely a bacterial bloom. And here, bacteria is not the nitrification bacteria but other types. If you want a fuller explanation, have a read of this article:
http://www.tropicalfishkeeping.com/freshwater-articles/bacteria-freshwater-aquarium-74891/

In my tanks I see slight haze after a water change which is usually completely gone by the next morning. If I clean the filters, as I happen to have done yesterday on the 115g, the haze is more significant and may last a day or two. But I let my canisters go longer than many would between cleanings so this may be part of it.

And I absolutely agree, never use clarifiers, for the reason AD mentioned. I speak from experience. Very bad stuff on fish.

Byron.
 
#8 ·
Oh, it's green cloudy water indicating an algae bloom? I must have missed that in your original post - I was thinking it was cloudy white/off white indicating a bacteria bloom. If it's green, you need to reduce the duration of the lighting.
 
#9 ·
It wasn't green when it first started to cloud up. That's what made me think it wasn't algae. 2 days ago it started to have a green-ish hue to the color. BINGO, algae. My wife has been leaving the light on all day(so I've come to find out), so I figure that helped cause the abundance of algae.
 
#12 ·
FINAL UPDATE:

Water is crystal clear now. Fish are still healthy. Wife is happy. All is well. Thanks for the advice/support.

I "fixed" it by doing a 50% water change, lowered my water level by a half inch (allowing more water movement from the filter), wiped off plants and decor by hand, did a gravel vac and glass wipe. Didn't use any chemicals (except to treat my tap water). Water just cleared up over night.

The water has been clear for over 24 hours now.
 
#14 · (Edited)
Initially, it was most likely just a bacterial bloom. Continuously turning on the light would almost surely result in green water. Not to mention the fish's stress. This is an effective Post. I found the same information on this tech blog abdulsguide.. Keep a watch out for ich, which is particularly common when the light is on all the time. Fish, like plants, require 6-8 hours of full darkness each night.
 
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