Islandvic
- #1
This is a write-up on some methods and options for using DIY media in your HOB filter. My goal is to condense in one thread, easy and cheap methods of improving the filtration in your HOB filter while making it more cost effective. I enjoy the hobby and especially the DIY aspect of it.
Have you become frustrated with replacing HOB cartridges and crashing nitrogen cycles? Is your filter not keeping up with the bio-load of your fish stock? Do you want to hot rod the stock filter your tank came with? Are you on a budget? Do you like or want to attempt some easy DIY projects that offer great results with minimal effort? If you answered yes to any of those questions, then you should be interested in this thread.
The following lists some DIY media options for adding coarse/fine mechanical filtration and for adding extra biological media to your HOB filters. It will work for 10 gallon betta tanks, 75 gallon cichlid tanks and anything in between.
I will focus on mainly the Top Fin Silenstream series of HOBs and also give some examples using Aquaclear filters. The Top Fin Silenstream filters are included with the majority of Top Fin aquarium kits from Petsmart. They are prevalent in our hobby and very cheap to buy separately. Aquaclear filters are on the other side of the spectrum of HOB’s. Between these two models of filter, most people will probably be able to use this guide to get ideas for the brand of filter they own with some minor tweaking.
This is not an all-inclusive list, but a general guide to give you ideas for cost effective, readily available and easy to use media for your HOB filter.
I will include specific media I have used in my personal HOB’s. There are many brands and variations of media available at different price points, for certain applications and specialty use. I can not list every brand/model of HOB filter or media. Again, this is a general guide to point you in the right direction.
What I demonstrate in this thread may not be applicable to your situation and needs. Sometimes experimentation is required in the amount/placement/type combination of DIY media to balance the flow rate, effectiveness of filtration and adjust to the tank’s biological load. You may tailor the DIY media to fit your specific needs and application.
Before I begin, I must thank everyone here on the Fishlore forum. I have gained a lot of information from a lot of good people. Everyone here wants to advance the hobby and are always available to give some advice or share their experience in a positive. Therefore I want to contribute back and share what I have learned.
There are many more great aquarium hobby channels on YouTube, but I cannot list them all.
Basics of Filtration:
Throughout the guide, the flow of water follows the same basic pattern through the media. It can apply to whatever your filter and media you choose.
Water enters the filter and flows through the media in this order then back out into the tank:
1st: Coarse mechanical filtration
2nd: Fine mechanical filtration
3rd: Biological filtration.
Water enters the filter where larger suspended particles gets trapped by the coarse mechanical filtration and smaller particulates gets trapped by the fine mechanical filtration. Then the biological media (where the beneficial bacteria colonizes) will facilitate the nitrogen cycle.
In this guide I purposely did not give options for chemical filtration, though if you choose to use it, I recommend it being the last thing the water touches before it flows back into the tank. I did not want to get into debates of the validity or specific times of when/when not to use chemical filtration.
Top Fin Silenstream filters and other cartridge based HOB’s:
The first example of using DIY media in a HOB will be for the Top Fin Silenstream series of filters. The Silenstream shares many design characteristics with other brands of HOB’s, so the DIY media mods listed below are easily adapted for use in other brands of HOB’s.
It’s a basic HOB filter design using a plastic bio-grid and a replaceable cartridge. They have a telescopic intake tube with a very handy adjustable knob that lets you adjust the flow rate. The knob turns a restrictor in the intake tube limiting the water flow that feeds into the impeller housing.
Top Fin is Petsmart’s in-house brand and the Silenstream filter is included with most of their Top Fin aquarium kits ranging from 10g-55g. Although considered an entry level HOB filter, with the right mods it can be made into a very reliable and effective filter. The following lists the gph ratings of the models. Although not indicated in the literature or online, I assume the gph ratings is for flow at the impeller assembly without media installed. Your actual gph flow may vary, especially when using different combinations of media.
Top Fin Silenstream 10 85gph
Top Fin Silenstream 20 100gph
Top Fin Silenstream 30 150gph
Top Fin Silenstream 40 200gph
Top Fin Silenstream 75 400gph
Models 20, 30 and 40 share the same filter body, intake tube and reservoir. The only difference is the gph ratings due to differences in the impeller/pump. The model 10’s reservoir is not as wide but has the same design as the 20-40 models. The Silenstream 75 model basically has 2 reservoirs joined together side-by-side with a stronger impeller/pump assembly rated for higher flow. Sharing the same basic design elements, the DIY media mods featured here can be tweaked for use in the 75 model also.
I own the Silenstream 20 model and it’s used in the following pictures. Although originally included with my 20 gallon Top Fin aquarium kit, it was re-purposed for use on my 10 gallon and I find it to be a very effective filter in this application.







Have you become frustrated with replacing HOB cartridges and crashing nitrogen cycles? Is your filter not keeping up with the bio-load of your fish stock? Do you want to hot rod the stock filter your tank came with? Are you on a budget? Do you like or want to attempt some easy DIY projects that offer great results with minimal effort? If you answered yes to any of those questions, then you should be interested in this thread.
The following lists some DIY media options for adding coarse/fine mechanical filtration and for adding extra biological media to your HOB filters. It will work for 10 gallon betta tanks, 75 gallon cichlid tanks and anything in between.
I will focus on mainly the Top Fin Silenstream series of HOBs and also give some examples using Aquaclear filters. The Top Fin Silenstream filters are included with the majority of Top Fin aquarium kits from Petsmart. They are prevalent in our hobby and very cheap to buy separately. Aquaclear filters are on the other side of the spectrum of HOB’s. Between these two models of filter, most people will probably be able to use this guide to get ideas for the brand of filter they own with some minor tweaking.
This is not an all-inclusive list, but a general guide to give you ideas for cost effective, readily available and easy to use media for your HOB filter.
I will include specific media I have used in my personal HOB’s. There are many brands and variations of media available at different price points, for certain applications and specialty use. I can not list every brand/model of HOB filter or media. Again, this is a general guide to point you in the right direction.
What I demonstrate in this thread may not be applicable to your situation and needs. Sometimes experimentation is required in the amount/placement/type combination of DIY media to balance the flow rate, effectiveness of filtration and adjust to the tank’s biological load. You may tailor the DIY media to fit your specific needs and application.
Before I begin, I must thank everyone here on the Fishlore forum. I have gained a lot of information from a lot of good people. Everyone here wants to advance the hobby and are always available to give some advice or share their experience in a positive. Therefore I want to contribute back and share what I have learned.
There are many more great aquarium hobby channels on YouTube, but I cannot list them all.
Basics of Filtration:
Throughout the guide, the flow of water follows the same basic pattern through the media. It can apply to whatever your filter and media you choose.
Water enters the filter and flows through the media in this order then back out into the tank:
1st: Coarse mechanical filtration
2nd: Fine mechanical filtration
3rd: Biological filtration.
Water enters the filter where larger suspended particles gets trapped by the coarse mechanical filtration and smaller particulates gets trapped by the fine mechanical filtration. Then the biological media (where the beneficial bacteria colonizes) will facilitate the nitrogen cycle.
In this guide I purposely did not give options for chemical filtration, though if you choose to use it, I recommend it being the last thing the water touches before it flows back into the tank. I did not want to get into debates of the validity or specific times of when/when not to use chemical filtration.
Top Fin Silenstream filters and other cartridge based HOB’s:
The first example of using DIY media in a HOB will be for the Top Fin Silenstream series of filters. The Silenstream shares many design characteristics with other brands of HOB’s, so the DIY media mods listed below are easily adapted for use in other brands of HOB’s.
It’s a basic HOB filter design using a plastic bio-grid and a replaceable cartridge. They have a telescopic intake tube with a very handy adjustable knob that lets you adjust the flow rate. The knob turns a restrictor in the intake tube limiting the water flow that feeds into the impeller housing.
Top Fin is Petsmart’s in-house brand and the Silenstream filter is included with most of their Top Fin aquarium kits ranging from 10g-55g. Although considered an entry level HOB filter, with the right mods it can be made into a very reliable and effective filter. The following lists the gph ratings of the models. Although not indicated in the literature or online, I assume the gph ratings is for flow at the impeller assembly without media installed. Your actual gph flow may vary, especially when using different combinations of media.
Top Fin Silenstream 10 85gph
Top Fin Silenstream 20 100gph
Top Fin Silenstream 30 150gph
Top Fin Silenstream 40 200gph
Top Fin Silenstream 75 400gph
Models 20, 30 and 40 share the same filter body, intake tube and reservoir. The only difference is the gph ratings due to differences in the impeller/pump. The model 10’s reservoir is not as wide but has the same design as the 20-40 models. The Silenstream 75 model basically has 2 reservoirs joined together side-by-side with a stronger impeller/pump assembly rated for higher flow. Sharing the same basic design elements, the DIY media mods featured here can be tweaked for use in the 75 model also.
I own the Silenstream 20 model and it’s used in the following pictures. Although originally included with my 20 gallon Top Fin aquarium kit, it was re-purposed for use on my 10 gallon and I find it to be a very effective filter in this application.






