Filters

[Townie]

Hi,

We have a relatively new aquarium and after ~8 weeks, finally have it cycled (probably not stable yet but fish have stopped dying). However, we sort of undersized our over-the-side filter unless we only want to lightly stock the tank (according to 2 aquaculture scientists I know and the fish health specialist at the better of the local shops). My engineer’s brain thought a 50 gal Aqua Clear would be 20% over capacity for a 40 gal tank.

So this week we added a sponge filter to increase capacity and split the load. We can’t really add any old media to the new filter to speed it along so how long should we reasonably expect before the new filter is also cycled? Will adding nitrifying bacteria help.

Thanks!

[Andy Sager]

Hi and welcome to the club.
To start, a cycled tank is one that has completely developed a bacteria bed of nitrifying bacteria that keeps ammonia and nitrites at 0. A " stable" tank is a cycled tank that doesn't have any issues with the bacteria bed. This happens with time. The bacteria bed grows and shrinks to the level of ammonia production in the tank. A newly cycled tank means there are enough bacteria present to handle the ammonia load at the time. This can easily be stressed by adding too many new fish too soon. Some call this a "re-cycling" of the tank as you will see a rise in ammonia if this happens. The good news is that the bacteria reproduce quickly so the "re-cycling"
process is very short. Because with time there are more things in the aquarium creating ammonia, in a stable tank, you probably wouldn't see any results of an ammonia test after adding new life to the tank. So they are close to similar but just not exactly the same.

To help with the other questions, you'll need to give us some more info regarding tank size, dimensions if it's not a " standard" tank, your water's chemistry and what kind(s) of fish you are interested in.

[Aiken Drum]

A good rule of thumb is to half the capacity a filter is rated for. So a filter rated 50 gallons is good for a 25g tank. There are other metrics such a flow rate and media capacity but it usually comes out around half a filters rated capacity.

As to how long it will take to cycle additional filter, this is a misunderstanding of what it means to be cycled. The microbes that consume the ammonia and turn it into nitrate will grow to the amount of ammonia available to it. Adding another filter will just give your filtration more capacity to grow, but with no additional ammonia the amount of microbes wont increase. What is likely to happen over a month or 2 is that microbes in your established filter will die off as new microbes colonise your new filter. The total amount will stay about the same and the ability of your filtration to remove ammonia will stay about the same. You would need to add more bioload for your cycle to establish further than it already is. Assuming you are cycled enough to consume all the ammonia your tank currently produces.

If your plan is to add more fish then do so gradually. This will ensure you dont massively increase the bioload in one go and overload your filtration too quickly. This gives your cycle chance to catch up, increasing the amount of microbes, before you again add a few more fish. Etc etc. If you are able to test your water, your target should be ammonia + nitrite no higher than 0.5ppm combined. If water parameters exceed this combined target, change some water to bring it down.

Are you able to test your water? Do you know what your water parameters are at currently? Preferably taken before a water change.

[Townie]

Originally Posted by Aiken Drum

A good rule of thumb is to half the capacity a filter is rated for. So a filter rated 50 gallons is good for a 25g tank. There are other metrics such a flow rate and media capacity but it usually comes out around half a filters rated capacity.

As to how long it will take to cycle additional filter, this is a misunderstanding of what it means to be cycled. The microbes that consume the ammonia and turn it into nitrate will grow to the amount of ammonia available to it. Adding another filter will just give your filtration more capacity to grow, but with no additional ammonia the amount of microbes wont increase. What is likely to happen over a month or 2 is that microbes in your established filter will die off as new microbes colonise your new filter. The total amount will stay about the same and the ability of your filtration to remove ammonia will stay about the same. You would need to add more bioload for your cycle to establish further than it already is. Assuming you are cycled enough to consume all the ammonia your tank currently produces.

If your plan is to add more fish then do so gradually. This will ensure you dont massively increase the bioload in one go and overload your filtration too quickly. This gives your cycle chance to catch up, increasing the amount of microbes, before you again add a few more fish. Etc etc. If you are able to test your water, your target should be ammonia + nitrite no higher than 0.5ppm combined. If water parameters exceed this combined target, change some water to bring it down.

Are you able to test your water? Do you know what your water parameters are at currently? Preferably taken before a water change.

Oh yes, we test it weekly using an API kit. As of Saturday, pH=7.2, ammonia=0, nitrite=0 and nitrate was between 0 and 0.25 ppm.

Thanks for the filter sizing information and on how cycling works.

[Aiken Drum]

Based on the ammonia and nitrite being zero you are cycled sufficient for your current bioload. If your plan is to add more fish then do so gradually and continue to monitor water quality as you do.

Your nitrate test result doesnt really make much sense. API test kits has zero as the lowest test result and the next result up is 5ppm. So im not really sure how you can tell its between 0 and 0.25ppm, its simply not that accurate. Also nitrate is the end product of the nitrogen cycle, so if you are cycled you should see nitrate. A few reasons why you might notbsee any.

- You arent doing the test correctly. Double check you are following your test kits instructions correctly. Really shake up bottle #2. Like bang it on the counter. If that doesnt get you any nitrate then get a 2nd opinion. Either try a different test kit or take a sample of water to a fish store and ask them to test numbers. If you go to the store make sure they give you numbers and write them down.
- You might be doing your test after a big water change, which would dilute things down. If so, do your test before your water change.
- Maybe you have a large tank and not many fish which wont produce much waste. How big is your tank? What fish do you have?
- Plants will consume ammonia and nitrate. Most plants in aquarium wont do this to any noticable degree, but if you have floating plants, terrestrial plants emersed in the water, or just a ton of plants filling the aquarium they could easily be taking up all the nitrogen going into the water. Do you have a planted tank? If so, what plants?

[Townie]

Originally Posted by Andy Sager

Hi and welcome to the club.
To start, a cycled tank is one that has completely developed a bacteria bed of nitrifying bacteria that keeps ammonia and nitrites at 0. A " stable" tank is a cycled tank that doesn't have any issues with the bacteria bed. This happens with time. The bacteria bed grows and shrinks to the level of ammonia production in the tank. A newly cycled tank means there are enough bacteria present to handle the ammonia load at the time. This can easily be stressed by adding too many new fish too soon. Some call this a "re-cycling" of the tank as you will see a rise in ammonia if this happens. The good news is that the bacteria reproduce quickly so the "re-cycling"
process is very short. Because with time there are more things in the aquarium creating ammonia, in a stable tank, you probably wouldn't see any results of an ammonia test after adding new life to the tank. So they are close to similar but just not exactly the same.

To help with the other questions, you'll need to give us some more info regarding tank size, dimensions if it's not a " standard" tank, your water's chemistry and what kind(s) of fish you are interested in.

Thanks for the info!

Our tank is just under 40 gal. It’s a narrower, taller design with a bow front. Bought it at a chain pet store so didn’t get good advice and undersized the filter. Also received bad advice regarding adding fish initially so we added fish too fast and had a lot of deaths.

By the time things cycled we were back down to 4 fish, 2 guppies and 2 platties that survived the whole cycling ordeal. We now have 6 guppies, 6 diamond tetras, 5 danios, 3 red miner tetras, 3 panda catfish, two platties and a pleco. In addition to the 50 gal aqua clear filter (I know, undersized) we’ve just added a sponge filter.

We test our water regularly and ammonia, nitrate and nitrite are close to zero now so the tank has been keeping up with the bio load. But a few people (2 aquaculture scientists I know and a fish health specialist at a smaller, local store) suggested the additional filter.

[Aiken Drum]

Just tidying this up a little as OP has 2 threads with commonalities, so i moved a few posts from the members intro into here to put it all together in 1 place.

Just to add, with that number of fish in that size a tank, you should be seeing nitrate so something is amiss.

[Townie]

Originally Posted by Aiken Drum

Based on the ammonia and nitrite being zero you are cycled sufficient for your current bioload. If your plan is to add more fish then do so gradually and continue to monitor water quality as you do.

Your nitrate test result doesnt really make much sense. API test kits has zero as the lowest test result and the next result up is 5ppm. So im not really sure how you can tell its between 0 and 0.25ppm, its simply not that accurate. Also nitrate is the end product of the nitrogen cycle, so if you are cycled you should see nitrate. A few reasons why you might notbsee any.

- You arent doing the test correctly. Double check you are following your test kits instructions correctly. Really shake up bottle #2. Like bang it on the counter. If that doesnt get you any nitrate then get a 2nd opinion. Either try a different test kit or take a sample of water to a fish store and ask them to test numbers. If you go to the store make sure they give you numbers and write them down.
- You might be doing your test after a big water change, which would dilute things down. If so, do your test before your water change.
- Maybe you have a large tank and not many fish which wont produce much waste. How big is your tank? What fish do you have?
- Plants will consume ammonia and nitrate. Most plants in aquarium wont do this to any noticable degree, but if you have floating plants, terrestrial plants emersed in the water, or just a ton of plants filling the aquarium they could easily be taking up all the nitrogen going into the water. Do you have a planted tank? If so, what plants?

Oops, always get those two reversed. Nitrate is between 0 and 5. 37 gal tank has 26 fish (6 guppies, 6 diamond tetras, 5 danios, 3 red miner tetras, 3 panda catfish, 2 platties and a pleco), taller tank. We also added a small live plant about 4 weeks ago that helps keep NHx down some.

We were down to 4 fish by the time we cycled the tank and have built it back up over the last 6 weeks. We just added a 40 gal sponge filter to supplement the 50 gal Aqua Clear (with 2 bags of bio max).

That’s where we are.

[Aiken Drum]

A small live plant with that many fish in a 40g tank isnt going to make any difference to nitrate. I would look to the other suggestions as to why your nitrate isnt as high as you would expect, with #1 likelihood there is something wrong with the test. Like said, really shake the heck out of bottle #2, bang it on the countertop, twist the bottle out of shape to dislodge the reagent from the side of the bottle. There should be a white residue visible in the drops.

[Andy Sager]

Here's a little secret with the API nitrate kit, you really have to shake the crap out of the nitrate reagents before testing. Historically, they seem to go bad before the expiration date and the chemicals go out of solution so you really need to shake them well to get them all dissolved again. If you still get the same results after doing that, take a sample of your water to your local shop to get it tested to see if your results are correct.

With the fish load you posted, you should be having a higher nitrate level.

[Townie]

Originally Posted by Andy Sager

Here's a little secret with the API nitrate kit, you really have to shake the crap out of the nitrate reagents before testing. Historically, they seem to go bad before the expiration date and the chemicals go out of solution so you really need to shake them well to get them all dissolved again. If you still get the same results after doing that, take a sample of your water to your local shop to get it tested to see if your results are correct.

With the fish load you posted, you should be having a higher nitrate level.

Just retested (actually, my wife did, not something for a colour-challenged person). Ammonia = 0, Nitrite = 0, and Nitrate = 5-10.

[Aiken Drum]

That makes a little more sense. Whats a normal water change schedule? How much? How often?

[Andy Sager]

Originally Posted by Townie

Just retested (actually, my wife did, not something for a colour-challenged person). Ammonia = 0, Nitrite = 0, and Nitrate = 5-10.

Yeah, unfortunately, anything color related is often a challenge for those with color blindness. Digital tests are just soo expensive for most of them. ) At least we have a more" normal" result.

[Aiken Drum]

Originally Posted by Andy Sager

Yeah, unfortunately, anything color related is often a challenge for those with color blindness. Digital tests are just soo expensive for most of them. ) At least we have a more" normal" result.

Has anyone ever tried the tetra test with the phone app which allows you to point the camera at the test vial and the app gives you the result?

[Townie]

Weekly, usually around 15%.

[Townie]

Thanks Andy! Everything seems to be settling in.