# Under substrate question



## tgsplano (Mar 20, 2018)

This is freshwater idea for goldfish but I don’t know if it’d work. Has anyone tried to raise their gravel bed above the aquarium floor just high enough to put in the ends of a few tubes to overflow out of the aquarium into a refugium? I was thinking some plastic canvas sheeting used for embroidery would hold the gravel up and allow waste to suction through. My thoughts is I keep the substrate a little larger than sand and not too thick. My hopes is to reduce how often I need to vacuum. Hopefully as waste and food breaks down, it’d catch in a filter in the capture tank below. Thoughts?


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## e.shell (Apr 14, 2021)

I just used some of that material to make incubation boxes for my monitor lizard eggs. Got it at "Michael's", a local craft shop chain.










It isn't very rigid and will not hold a lot of weight without having some sort of support under it. I'm sure it will sag under the weight of the gravel if not supported at least every 1-1/2" x 1-1/2", and might even require closer spaced support than that. You might be able to use it over a fluorescent light grid, sitting up on some sort of spacer.

Otherwise, the idea seems good and I know goldfish generate a LOT of waste, although they do shuffle through the bottom substrate and stir it up quite a bit.


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## JimE (Mar 21, 2021)

tgsplano said:


> This is freshwater idea for goldfish but I don’t know if it’d work. Has anyone tried to raise their gravel bed above the aquarium floor just high enough to put in the ends of a few tubes to overflow out of the aquarium into a refugium? I was thinking some plastic canvas sheeting used for embroidery would hold the gravel up and allow waste to suction through. My thoughts is I keep the substrate a little larger than sand and not too thick. My hopes is to reduce how often I need to vacuum. Hopefully as waste and food breaks down, it’d catch in a filter in the capture tank below. Thoughts?
> 
> 
> Sent from my iPhone using Tapatalk


i have a 75 gallon freshwater community tank;
Against multiple advice 


tgsplano said:


> This is freshwater idea for goldfish but I don’t know if it’d work. Has anyone tried to raise their gravel bed above the aquarium floor just high enough to put in the ends of a few tubes to overflow out of the aquarium into a refugium? I was thinking some plastic canvas sheeting used for embroidery would hold the gravel up and allow waste to suction through. My thoughts is I keep the substrate a little larger than sand and not too thick. My hopes is to reduce how often I need to vacuum. Hopefully as waste and food breaks down, it’d catch in a filter in the capture tank below. Thoughts?
> 
> 
> Sent from my iPhone using Tapatalk


I have a 75 gallon freshwater community planted tank. Against advice from several experienced fish keepers I use an under gravel filter in harmony with a canister. 
So far, so good. 
only a few months in, but so far, it seems to be a good combination. I don’t vacuum my substrate and do water changes only because I am being cautious. The water remains very clear, plants healthy, and nitrates, nitrites, etc. are all fine…
No algae, seems I could go without water changes, but not going to push my luck I do about 15-20 gallons every month, or so. Canister is clean, plants seem to be doing fine… fish are happy.


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## fishmanbob3 (Apr 18, 2019)

tgsplano said:


> This is freshwater idea for goldfish but I don’t know if it’d work. Has anyone tried to raise their gravel bed above the aquarium floor just high enough to put in the ends of a few tubes to overflow out of the aquarium into a refugium? I was thinking some plastic canvas sheeting used for embroidery would hold the gravel up and allow waste to suction through. My thoughts is I keep the substrate a little larger than sand and not too thick. My hopes is to reduce how often I need to vacuum. Hopefully as waste and food breaks down, it’d catch in a filter in the capture tank below. Thoughts?
> 
> 
> Sent from my iPhone using Tapatalk


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## fishmanbob3 (Apr 18, 2019)

Sounds like a great idea, what exactly is a refugium? A diagram would be extremely helpful.
Regards. 
Bob E.


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## e.shell (Apr 14, 2021)

fishmanbob3 said:


> ...what exactly is a refugium?...


I didn't know either:
Refugiums


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