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Cloudy water


11 Sep 2010
Manchester, UK
Hi all,

Recently I noticed my water has become a little cloudy and it is nowhere near as clear as my friends planted tank. Please see below image. I'm wondering If it's my filtration system? Any ideas would be appreciated, I've looked into the overfeeding etc and it isn't because of that.



Edited to place image inline: ceg4048
Hi all,
I don't know what the cause is, but a very fine "water polishing" filter will clear it, the usual one is "diatomaceous earth" based, but you'll probably be able to get rid of it with a fine polyester floss. You can either buy filter floss pads or make your own from the stuff they sell for upholstery, the search term you want is "polyester batting", this is a much cheaper option.

cheers Darrel
Thanks for the reply mate, I will give this a go, do I just cut it out and add it into my filter? Cheers
Hi all,
Thanks for the reply mate, I will give this a go, do I just cut it out and add it into my filter? Cheers
Yes you can put it in loose, if there is a tray? If you thing it might end up in the impeller, you can put it in one of those nets bags you get for ceramic rings etc. If you haven't got a "media filter bag" I've used the nets that satsumas, garlic etc come in or an old pair of tights. You need to put it somewhere you can geet at fairly easily, because it is very fine it will clog really quickly.

Should also have said you need the cheap polyester batting, if it says "fire retardent" it isn't suitable.

cheers Darrel
Yeh I will cut it to fit one of my trays and put it under the White filter media that's already in there. Regarding the batting I actually bought some before you posted your last message off eBay. It says fire retardant so i guess that won't work.

Westyggx said:
Recently I noticed my water has become a little cloudy and it is nowhere near as clear as my friends planted tank. Please see below image. I'm wondering If it's my filtration system? Any ideas would be appreciated, I've looked into the overfeeding etc and it isn't because of that.
OK, had to study that image for quite a while to make any sense out of it since there was not enough data in the post.

Did you take that picture with the filter turned off and with CO2 off? I hope the answer is "yes" because unless it's an optical illusion, I can see white film on the surface and I can't see any rippling of the surface or bubbles from the diffuser. Is that long gray tube in the back that looks a bit cockeyed a spraybar? It also looks like there is an internal filter in the lower left corner. If the answers to these questions are also "yes" then is it a valid assumption that you are using both an internal filter and an external canister + powerhead on this tank?

All this should have been clarified in the OP. That's because there are la couple of reasons for cloudy water that have little to do with filter media. For example;
1. Dosing certain trace mixes with hard tap water in tank can result in precipitates which cloud the water.
2. Uncontrolled ejection of lipids due to poor nutrition/CO2 can result in bacterial blooms that feed on these ejected products. These bacterial blooms are characterized by a milkiness. The poor nutrition could be caused either by poor nutrient dosing/poor CO2 injection rate or by poor flow/distribution.

It's unlikely that the tank would have been clear on day and then cloudy the next simply due to the need for more filter material. What has been the pattern of water clarity? Is the tank newly setup? Some sediments, such as clay based, naturally produce a lot of particulates even if initially washed, but this usually clears with time. In those cases additional media helps, but that photo doesn't look like a clay sediment. Even so, if you didn't do a good job of washing, and if the tank is young, fish digging in the sediment, or hands moving it around to rearrange plants and so forth might kick up particulates to cause the cloudiness.

Assuming the cloudiness was not due to disturbing the sediment, increased mechanical filtration may not be the answer. If the cause of the cloudiness is either chemical or biological, then stuffing your filter with additional material may actually lead to more problems due to reduced flow.

In any case, if this is a particulate issue then adding more polishing media will definitely help, but if is not a mechanical issue, then you may continue to struggle with this. All I'm saying is that without more data regarding tank configuration, age of the setup, dosing practice, water type and so forth, we cannot assume one cause or another.

Hi could you please advise on the substrate / fish within the tank. My thoughts are that you have a sand based substrate and the fish are distrubing the bottom (which cats would do) which in turn is clouding the water.

The filter in the left hand corner is the intake strainer for the external filter and behind that on the outside of the tank is a bubble counter, there are bubble being emitted from the diffuser tiny bubbles are visable

Apologies on the poor post. I am using my iPhone to post here at the mo, picture is poor due to moderator including the small pic to this thread.

To answer the questions, this tank is not a new setup it has been running for about a year. The fish I have to not rummage into the substrate either.

The thing on the left is a inlet as per above post with a bubble counter on the glass behind. If I'm Honest I think this has been like this since I installed the external filter, water was clear when I had an internal. There is also a power head top left point to the diffuser to disperse the bubbles, do you recommend this to be pointing to waters surface?

Now It may be that my filter isn't up to par with the dosing and co2 I am doing it is a aqua one 700.


It could be down to a lack of cleaning out the filter unit - sponges are not doing their job correctly (sorry to say that) when was the last time you cleaned out the filter unit, its advisable to clean the filter ever 4 -6 weeks. The flow from the powerhead is not distrubing the substrate ?. If you twist the head upwards to much you will distrub the surface too much you will vent the residual co2 within the water column.

Does your filter unit have a polish pad or very fine white filter fitted if not buy a sheet of hollow fibre filler of the market, its the same material that they fill pillows / cont. quilts - like this http://cgi.ebay.co.uk/Pond-Filter-Mat-M ... 588996fb8d but a smaller quantity, you will have to cut it to suit your filter and place it in the top filter tray or the first tray when you remove the head unit.

Hi Paul, I gave the filter a good clean about 3 weeks ago, It does not have a fine filter media as you are describing I do actually have some of this from old internal so I am going to cut some to fit the basket size.

Thank you
So i change the filter pad last night Paul, wake up this morning to see the same situation :/

I thought i would hijack the end of this thread as i am having a similar problem.

My tank has been setup about 4 weeks, this is my first attempt and i thought all was going well. The tank is 24'' x 8 x 8, 1 24'' T8 Bulb, no c02.
About a week ago i had a massive algae outbreak, green string like algae growing from most surfaces, rocks turning green and plants being wrapped up in algae webs. After reading several forums i decided to start dosing with flourish excel. I added 2 cap full the first day and one cap each day after, i have done this for 3 days. Now my tank has become very cloudy, could this be caused by the flourish excel?

I am running an internal filter that i cycled in an existing tank i have, about a week ago the reading were, Ammonia: 0 Nitrite: 0 Nitrate: 10. Its sods law as i have just ordered some CRS shrimp for the tank which should be here tomorrow.

Any ideas whats going on?

p.s. I was running the lights for 10 hours a day before the algae outbreak (too much i know) now i am running the light for 7 hours.
Ok so i got to a computer and can type this out properly for more help.

125 Litre Tank
Co2 at 1bps
Aqua One Aquis CF700 External Power Filter
Dosing is an all in one solution Nitrogen, Potassium and Phosphorus (NPK), E300 , E202 i dose 15ml of this a day
I dose 10ml of Easy carbo each day
Lights come on 2 hours after Co2 and stay on for an hour after co2 has stopped.
The substrate is Sand.

I am starting to wonder whether i rushed into buying my filter im pretty sure its not up to par with the size of my tank.

If anyone could help that would be great.
Ok so I bought a new filter tetra tec 1200 an the tank I'd clearer but clear enough it looks hazy. Any adivice now you know my set up? Cheers