How often to replace certain elements (e.g. Filter media)

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Aquarium Advice Regular
Sep 27, 2022
I'm relatively new to fishkeeping, and after a very rocky start, now have a stable tank. However I've found out some advice I was given, and even instruction on packaging has been 'wrong'/not necessarily what's best for the tank. So I'm just looking for some advice on the below:

1) How often to change filter media?
1a) - I currently have 2 pumps in my 60l tank (was advised to help with a crashed cycle), and Aqua flow 300, and an Aqua flow 200. The packaging says to replace the internal media once a month, which I had since been advised was far to frequent, and was one of the causses of my rocky start.

2) How often to change phosphate remover?
2a) To try and combat some algae growth, it was found my phosphate levels were a tad high, so I now add phosphate remover in to my filter media in a small mesh bag. How often is it worth replacing this? (I use roughly 1/2 or 1/3 of a full bag advertised)

3) how often to change carbon?
3a) similar to the above, how often should the carbon inside the filter media be replaced?

4)How often and amount for water changes
4a) have had some mixed responses of water changing percentages and frequency, but what seems to be the norm? at the moment I do about 20% weekly, and about 30/40% once a month as a bit of a deep clean of the tank.
Is this your filter?

I would ditch however you set it up and set it up as the video. Just substitute biohome for any biological media. Richard has a financial interest in biohome, although i do like it as a filter media. Maybe do one filter, leave it for a couple of months then do the other so it minimises the effect on your cycle. Set up as per the video you wont need to change the filter media for years, maybe decades.

To answer your question though.

Mechanical media, so sponge, should only be replaced when its falling apart, and this should be years down the line. Apart from that it needs a periodic rinsing in dechlorinated water to prevent it clogging up and preventing water flow. I typically do this every 4 to 6 weeks.

Biological media, so thats the ceramic rings and biohome in the video, again should only be replaced if its falling apart. And this should be decades. Again a periodic rinse with dechlorinated water when you rinse your sponge to clear of detritus.

Chemical media, so this is the carbon and phosphate remover. These have a shelf life before they need replacing.

Activated carbon typically lasts 2 to 4 weeks. Phosphate remover impossible to say. Monitor phosphate, when it starts rising replace or rejuvenate. Most people change it monthly, some people manage 6 months.

Big "but" coming. Just get rid of the chemical media, its probably not doing anything useful. Just set it up as richards video.

Activated carbon removes organic compounds and some metals from the water. These organic compounds can be tannins from driftwood which cause tea like colour in the water, so carbon is often used in new tanks to get the water clear until the tannins have leached out. Organic compounds can cause odours so carbon is used to remove these odours. After a course of medication you want to remove the medication from the tank and carbon will do this. If you arent dealing with any issues then carbon isnt doing anything. Tannins eventually leech out, tanks dont smell if you keep up with maintenance, medication should only be used to treat a known disease and then discontinued. Use carbon for a specific short term issue, once its resolved stop using it. It needs replacing regularly, its expensive, and most of the time of no benefit.

Phosphates are blamed for causing algae growth and this just isnt true. If you have an algae problem, high phosphate can make it worse, but on its own it doesnt cause algae. You are far better dealing with algae by dealing with the cause, which is usually excessive light and nutrients. If you have plants in the tank they need the phosphate anyway.

Water changes. Do your normal water change and test for nitrate a week later. If nitrate is above 40ppm thats OK. If its below 20ppm even better. You can stick to that weekly water change routine. If nitrate is above 40ppm, increase the amount of water changed. If a 50% weekly water change isnt keeping nitrate below 40ppm you are overstocked. Remove fish or get a bigger tank.
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And just to add. Those 2 filters together are massive for a 60 litre tank.

The 200 is rated for 100 to 200 litres. The 300 is rated for 150 to 300 litres. Together you have filters rated for upto 500 litres. Even by my metric of halving the rated filtration you have sufficient for 250 litres of water, so 5x the amount your tank holds.

I really dont see the benefit to over filtering to that degree, and unless you can turn the flow rate down to a significant degree the flow of water must be tremendous. Its not like if 1 filter can cycle the tank, having 2 filters will cycle it more. Your filtration will hold as much beneficial bacteria as needed to remove the waste your fish produce. Adding a 2nd filter will only help if the 1 filter isnt enough.
The reason behind 2 filters was that i essentially had a smaller 200 version, and had a cycle crashed, so the 300 version was reccomended due to the ceramic rings, and was advised to leave both in their for the best chance of at least one developign bacteria. Since i have left both in, one pointing upwards to the surface, and one pointing towards the gravel (to help a previous issue of algae development). i also then use one to house the phosphate remover, and one to hold the carbon. I was advised theres no harm in leaving the both in, but again, am never sure on if the things that get mentioned are true or not.
If your fish are comfortable with all the water flow, there's no harm in keeping them both. Its just unnecessary.

Your cycle didn't crash because your filter was too small. It could have been set up better as per the video so changing filter media didnt cause a crash. An earlier thread of yours suggested it was caused by replacing the substrate.

Was the recommendation to add a 2nd, bigger, filter made by someone trying to sell you a 2nd, bigger filter?
Yea thats right, it was deffinitely the substrate change that caused the major crash, so the fish store suggested addign the second filter with the ceramic rings as an extra media to try and encourage bacteria development. The only other reason i ve left both in was out of fear of causing another crash by removign one media (espeically if there was an instance where only one had actually developed basteria at the early stages and thats the one i removed)
Important lesson learnt. People in stores often know no more than you do about keeping fish. If they do know, they are instructed on what advice they can give which is driven towards selling you stuff you dont need. One of the girls in our local pets at home is a hobbyist, and her job is under threat every time she gives honest, good advice, that might discourage a sale. She will still sell you a goldfish for a 40 litre tank if you insist on it though.

If you want to remove a filter, just gradually remove filter media from the filter you want to omit over a period of a couple of months. That way the microbes can slowly catch up in the media left in the system until one is empty and can be removed.
That makes sense, if i was going to remove one, my plan was to turn the filter off, remove the media, but place it by the remaining filter for a few weeks to ensure their was still 'flow through the bacteria".
In your opinion, am i better off leaving both filters in, or should i remove one? im assuming there is no right/wrong answer here as the tank is doign fine, but am just wondering if having the 2 is overkill (again, the store told me somting along the lines of " you can have as many filters as you want, theres never too much"
You can take the media out of the filter and put it somewhere that has good flow if you like. But at some point you will be removing it. Now or later, doesnt really matter. At some point you will be removing the filter media and the microbes that live on it. Either way just dont remove it all at once.

Do you need to remove a filter? Ill go back to my post #5. If the fish are happy with the level of flow its fine. Those 2 filters combined are rated for almost 1000 litres/ hour. These flow rates are calculated for optimum conditions, so empty of media, minimal head difference etc. But even if we half the flow rate for real, in use circumstances those 2 filters can turn over 500 litres/ hour or the entire volume of water in your tank around 10x per hour. Thats a lot and too much for some fish. Im not sure if you can adjust the flowrate down on those filters. If your fish seem comfortable in the flow then its fine.

Personally, i wouldnt over filter to that degree as its of no benefit. The amount of microbes in the system will grow to the amount of ammonia, it doesnt grow to the size of the filtration. The 200 is more than sufficient for a 60 litre tank if set up properly. If nothing else the additional power cost of the extra filter would be a consideration.

Or, might be a good excuse to get a bigger or 2nd tank as you already have a filter available.
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