# Expanded clay - awesome / cheap biofilter media



## DogFish (Jul 16, 2011)

I think you may find Hydroton or the knock-offs not only are very dirty, they will break up fairly quickly in the higher flow found in most filters.

That's part of why I chose Growstones vs. Hydroton.

Unfortunately they are too pricey unless you have a monster sump to feed.
A good inexpensive Home Depot alternative is lava rock gravel.


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## AVN (Oct 3, 2012)

I love lava rock, I have maybe close to a ton of it.


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## RobMc (Oct 16, 2012)

Thanks for the tip dogfish, I'll definitely check out the lava-rock. Sounds like a good substrate too, for larger applications.

Would it help to have a decelerant in the filter (like loose sponge) before the hydroton? Was it broken up by the water rushing directly from a small inlet?


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## TexasCichlid (Jul 12, 2011)

Lava rock is a relatively poor choice in terms of surface area and it plugs up easily. For bio media it is difficult to beat plastic pot scrubbies and or scour pads.


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## AVN (Oct 3, 2012)

Didn't say I used it as filter media in a HOB or canister! It's good substrate and great for inexpensive wet/dry.


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## RobMc (Oct 16, 2012)

Scour pads! Brilliant!


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## AVN (Oct 3, 2012)

Don't use steel scouring pads. In fact, you can get scrubbing nylon loofahs for $1 at most places and they have more surface area than most filter media per sq. inch.


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## Seattle_Aquarist (Jun 15, 2008)

RobMc said:


> Hey guys, was perusing Home Depot and stumbled upon some expanded clay - a media usually used to grow hydroponic plants. Sometimes called Hydroton (the kleenex of expanded clay).
> 
> It costs <$10 for ~10lbs of the industrial biofiltration media of choice
> (as in this study on denitrifying processes of wastewater treatment http://www.ncbi.nlm.nih.gov/pubmed/22277236)
> ...


Hi RobMc,

FYI, Hydroton has been discontinued by the manufacturer.


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## TexasCichlid (Jul 12, 2011)

Here is a nice thread comparing filter media.

http://www.monsterfishkeepers.com/forums/showthread.php?88677-Beginners-Guide-to-Filter-Media


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## steak (Sep 3, 2007)

Just want to reinforce lava rock defense. I have been using it for 3 years now. Does the job fine. I have never had to wash it.

Gravel of any sort in women's pantyhose worked for me as well. 

Ceramic cylinders that came with one of my filters worked too.


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## DogFish (Jul 16, 2011)

The Bio-Media concept is based on using some sort of mechanical pre filter so it does not load up with degree. 

You not going to beat Lava rock for CHEAP, and that is the topic. Yes, plastic srubbies work, but 20" Green or Black Floor Scrubber pads food commercial
floor scrubbers will work even better. They a regularly used in DIY pond filters.


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