Anyone use fiberglass or resin faux landscaping rocks?

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Modest_Man

Polypterus
MFK Member
Jul 5, 2006
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I have a 400 gallon and want to put in some large rocks for scaping. Specifically, I want to cut a faux rock to fit around my center overflow to hide the overflow and returns. I have plenty of real, large rocks around but the weight of getting them into the tank is prohibitive.

I was wondering if anyone has use the moulded fake/faux landscaping rocks. Looks like they are mostly an inert resin or fiberglass and would look pretty good in the tank, especially after some time. I could also drill holes in the back of some medium sized ones for some caves/hideouts.

Similar to this - Fake Rocks

I know there are similar things out there specifically for aquariums, but they tend to be 4-5 times the cost and I don't want to shell out several hundred dollars for a fake rock.
 
I haven't. My plan is to zip tie to a section of egg crate and put a real rock on the crate. The crate will be buried in sand.
 
A note from a vintage Boston Whaler owner/forever-restorer:
Polyester resins are cheap & common, but not insoluble nor waterproof - they will degrade with submersion. Either use an epoxy resin, do the final layer of glass with an epoxy resin or apply a sealing coat to seal the Poly from the water. There are a few options for that sealing layer - epoxy is the usual, but it's costly & still takes a few coats to seal properly.

Sorry, I don't know/can't speak to the toxicity of the dissolved resin, but assume that your charcoal will remove it.

Note: my lily-flowerpots are fibre glass mat with cement as resin/matrix. Soak in a bucket for at least a month, or just leave it in the rain until moss starts growing- then you know it's Ok. It's nightmarishly itchy to work with and droops terribly, but the end-point can be very cool.
 
I don't think it's polyester. It needed to be weighted down. Polyester resin density is 1.09 g/cm3 ish and should sink. Im thinking it's probably polyethylene?
 
It does say plastic on the menards page so I would assume as long as the color is solid through then would be safe. I get worried about painted plastic because the paint flakes off
 
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