Question about PWC and brown water from filter.

So I've been doing weekly 50% water changes until this past christmas weekend, so I missed one week of PWC. So this week I did a 90% PWC then refilled the tank to 30% full and took the water back down to 10% twice to make sure I can get as many nitrates out as possible. I also took the filter out and rinsed it in a tub of the old water. Then I grabbed the filter cartridge, dipped it into the old water and rubbed it down a bit (water got really brown afterwards). After everything was done, I plugged everything back in and the water coming out of the filter was cloudy brown. This has happened the past few water changes. Is there something wrong with the filter or is this usual since cleaning out the filter cartridge completely would kill all the beneficial bacteria?

When you rinse filter media you loosen the debris in the filter and while some of it is rinsed out, you can't ever really get it all out.  When you turn the filter back on, some of that stuff gets spit back into the tank for a brief period of time.

So to answer your question - this is normal, don't worry about it.  Though I'm not sure I would do a 90% followed by 2x immediate 20% changes just to make up for a skipped week.  Some aquaria can handle that sort of abuse, but some can't.

My filter spits out junk after I rinse it, the water usually clears up in a few hours. You probably shouldn't do that big of a water change and clean the filter at the same time, you will kill off too much of your beneficial bacteria and cause the tank to have to re cycle.

Most of my tanks get a 40-50% water change about every 5-7 days depending on stocking levels.  I run multiple filters on all tanks except my smallest so cleaning one of the filters at water change time is not a problem.  What can be a problem is if the filters have gone too long between cleanings.  My small HOB's are on a weekly to bi-weekly cleaning cycle while most of my canisters on a monthly cleaning cycle.

You can have an issue when you have gone too long between filter cleanings ... where when you clean the filter it causes a mini cycle to happen.  You can smell it ... the water will develop an odor within 1/2 day of that cleaning.  Keeping a biological filter supplement  like Nutrafin Cycle on hand for just such cases and doing a maintenance dose when you see that your filter is really dirty on the cleaning will help you head off that mini cycle before it happens.

 This is one reason to over filtrate. If the system is over filtrated and you clean up to half the filter media at a time I find no loss in the tanks bio health.

*A bit of clouding during filter maintenance is normal.


I always fear a hard parameter flux with large water changes & never do a water change more than 20% at a time unless I have to. Everyone does things different this is just from my experience.

Problems with large water changes occur when the replacement water is very different than the tank water. A $20 TDS meter will make things much easier in this respect. Like cichlid-gal I have at least two filters on all tanks which makes cleaning them, and the possibility of killing bio-filter bacteria, less of an issue. I also keep mesh bags of bio media in all filters to harbor bacteria, allowing me to clean the sponges/pads/inserts under the tap and get them muck free. The bags of bio media get a rinse in the bucket of tank water. I rarely have anything cloudy washed back into the tank after cleaning and I've never had a lapse in cycle. I clean my HOBs maybe every 2 or 3 months(only when flow is obviously restricted) and cannisters a little less often. I do use pre-filter sponges on most intakes that are rinsed with every water change.

I checked my ammonia this morning and it read 0, so luckily there was still enough beneficial bacteria. I have only 1 filter, which is an eclipse 3 hood :/