# Calling All Experienced Background Builders



## BayerFoot (Mar 18, 2019)

I have scoured the forums and the search tab trying to gain as much information as I possibly can for building a background [for a paludarium] and I have some questions I just cannot seem to get the answers I need.

1.) is it better to build the background out of the tank or build it in the tank?

2.) The design I am going for will include a small stream to waterfall down into a pool that will gently overflow into water. I've read on other threads there are folks out there who are going to tell me "DON'T DO IT!" however, can I make a "skeleton" of egg crate for structural integrity and cover with GS pond foam? Plumbing will be built in and waterways "coated" with silicon. 

3.) Can this foam be "manipulated" (smoothed out or shaped) before it completely sets? I'm not intending on sculpting the next David by any means, just curious if I can help mold it. 

4.) Can substrates be applied to the foam as its curing (while still wet) and will it stay? Say, either a dampened sand and/or peat mix as I understand water helps cure the GS. I did see a thread where a person added sand (dry I believe) to it while it was just sprayed out, and it does expand while curing I know and so the protruding new foam did not have a sandy coating, person added grout which leads to next question-

5.) For a hopeful planted background is it better to have a more aggregate type coating (sand/mortar/grout) for the GS foam-or-peat mix and silicon (which I read doesn't always "stay")? 

6.) Has Anyone ever successfully incorporated either mediums (sand and peat mix)?

7.) Lastly, for a hopeful planted background, did you supply the "pots" or crevices with drains or layer with drain stones on bottom?

Thank you for "Bayering" with me.


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## Tanks (Jan 14, 2019)

Hello 🙂

1) Gs foam sometimes peels off the glass, especially the pond and stone foam. The foam also shrinks a little while curing. I build mine in separate pieces, both in and out of the tank, and then silicone it all into place after I’m sure about fitting and placement. Cleaning the glass with rubbing alcohol will help everything stick better. 

2) yes, that’s kinda how I built my last waterfall/stream. I foamed the pieces out of the tank, carved them out, and fit them into place.

3) no..once the foam is spayed on, anything that comes in contact with it while still wet will become covered in sticky goo that’s impossible to remove..knives, blades, fingers, fabric. I would suggest using a little extra foam, letting it set over night, and then carve away what you don’t need. And wear gloves lol

4) yes, but you said it..the expanded foam won’t have medium in it and you’ll probably still have to cover it with more substrate 

5) natural fibers retain moisture better but eventually break down...though if it’s covered in plants then I guess it doesn’t matter? Tree fern fiber seems to be the best fiber background for moisture retention and getting plants to grab a hold better, imo. I’ve never tried clay but I hear it works great.

6) my latest tank is a mix of coir, tree fern, eco-complete, and sand. Some parts are just coir and sand for a dryer area, some parts are all tree fern for a more moist area. The eco complete was added just for aesthetics. After drying, I pinned down dried Lfs with toothpicks to get vines to root on the back wall. 

7) yes, all the wall pots have good drainage..holes in the bottom and a layer of lava rock. With high humidity, the roots may rot if they’re not allowed to breath or dry out.


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## Dane (Aug 19, 2004)

BayerFoot said:


> 1.) is it better to build the background out of the tank or build it in the tank?
> 
> 2.) The design I am going for will include a small stream to waterfall down into a pool that will gently overflow into water. I've read on other threads there are folks out there who are going to tell me "DON'T DO IT!" however, can I make a "skeleton" of egg crate for structural integrity and cover with GS pond foam? Plumbing will be built in and waterways "coated" with silicon.
> 
> ...


1. Depends on the complexity of the design, and whether there is the potential need to remove background and substrate to sterilize the tank for re-use with different occupants down the road.

2. Don't do it...unless you are determined to make the same mistake that every other newbie has despite overwhelming advice to the contrary. Successful ponds and water features require a lot of expertise in methods and materials, as well as animal husbandry and plant selection.

3. Yes. Once GS has skinned over, it can be compressed and lightly shaped. The workable window will be short, and it takes some trial and error to figure out the limitations of this method. Attached is a photo of a few GS backgrounds I have made WITHOUT any carving involved, just careful application and manipulation of the foam as it cures.

4. Yes, you could apply your texture layer directly to the foam while it is wet, but the end result will require lots of touching up, and won't yield as appealing a finished product as the tried and true silicone smear.

5. Once some humus has developed on your coco fiber layer, most trailing/vining plants will have no problems crawling up your background. Getting that picture-perfect moss wall however, will probably require carefully planned lighting, misting, and air movement schedules.

6. I regularly use sand and peat in my background coatings.

7. When I foam in pots as planting points, I leave the bottom of the pot open and clear of foam, so that drainage isn't an issue.


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## Leeb10 (Mar 24, 2019)

Is a background beneficial to frogs? I'm new to frog keeping.


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## Dane (Aug 19, 2004)

Leeb10 said:


> Is a background beneficial to frogs? I'm new to frog keeping.


They improve the usable space for the frogs themselves. Bare glass does little to encourage plant growth, or increase biomass. 
If you are dealing with a strictly terrestrial species, then it's more for aesthetics.


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## jgragg (Nov 23, 2009)

> Don't do it...unless you are determined to make the same mistake that every other newbie has despite overwhelming advice to the contrary. Successful ponds and water features require a lot of expertise in methods and materials


Hilarious. There seems to be something in human nature that recoils at the prospect of learning from others. Learning to the point of modifying our actions in advance, I mean.

Anyway, that said - how's a guy supposed to get expertise in materials and methods? There's truly _no substitute for experience_.

OP - best advice I can give, is play around some first without your tank. Like, spray your first couple cans onto cardboard boxes and pieces of scrap glass and eggcrate. Learn how the materials behave, and what you can - and can't - make them do. Once you've got a little bit of experience - which is the mother's milk of _warranted_ confidence - then get your tank out and give it a whirl.

I can't help adding - you don't _need_ to use spray foam, or any foam. And, a drip wall is way more forgiving than a stream and pond, for a first adventure into in-tank plumbing. Finally - drain it out a bulkhead. Just do it.

Good luck!


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## Squibles (Mar 7, 2019)

Dane said:


> 1. Depends on the complexity of the design, and whether there is the potential need to remove background and substrate to sterilize the tank for re-use with different occupants down the road.
> 
> 2. Don't do it...unless you are determined to make the same mistake that every other newbie has despite overwhelming advice to the contrary. Successful ponds and water features require a lot of expertise in methods and materials, as well as animal husbandry and plant selection.
> 
> ...


Thanks for sharing this information. I am working on a custom background myself and this is very helpful.


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## BayerFoot (Mar 18, 2019)

Thank you all for your varying tid bits of information and experiences. Sorry for my late reply, it's going to happen this time of year (rancher and this is calving season). I've used spray foam before, but never in a tank (we use it to seal grain bins and I converted an old dead fridge into grain storage in the barn). Loved the suggestion to practice on scraps. 

I'm not a complete stranger to the whole tank/terrarium thing. I've had many critters in the decade of working at one of the largest fish stores in the upper Midwest. past life hahaha. So, being that there was a foot in the puddle once, it's appealing to try something I always wanted to before "life" happened and courses changed in 2010 (paludarium). Inhabitants are undecided; creating environment first. 

I can say this, a lot of the "gadgets" have changed over the years ESPECIALLY in lighting- WOW! 

all of you, thanks again for your inputs!


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## Dr. Manhattan (Oct 28, 2016)

I made the backgrounds in these 2 tanks out of rigid foam and Loctite spray foam. For the "rocky" look I made a mix/slurry of peat moss, coconut coir, Titebond 3, Drylok latex masonry waterproofer, Quikrete concrete dye, and some different shades of acrylic craft paint. I built both tanks my self out if plywood. The one on the right ultimately failed due to me not being able to solve the liquid rubber waterproofing material/glass interface. The tank on the left I turned into a jungle vivarium for my geckos, no water features. The backgrounds in both.......indestructible. I say that with no hyperbole. I can't remember what the exact ratios of my mixes were but I knew I could put it on with a brush. Like jgragg says trial and error (as long as nothing is harmed) is great for experience. There's a guy on here called the Deeb, he's been my go to guy for any advice or inspiration when it comes to paludarium backgrounds.


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## davecalk (Dec 17, 2008)

I have used foam for years in this kind of application. Works well.

Using colored foam for backgrounds & tank construction.

I describe the process and how to shape and mold the foam back in 2009. 

I would never go back.


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## davecalk (Dec 17, 2008)

Tanks said:


> Hello 🙂
> 
> 1) Gs foam sometimes peels off the glass, especially the pond and stone foam. The foam also shrinks a little while curing. I build mine in separate pieces, both in and out of the tank, and then silicone it all into place after I’m sure about fitting and placement. Cleaning the glass with rubbing alcohol will help everything stick better.


Good point about cleaning the glass. 

There are a couple of helpful tips to ensure there is proper bonding.

On the base level where it attaches / bonds to the glass you can use a polyurethane glue like, gorilla glue as a base. Mixing color into the glue is a good idea if you want the exterior side of the tank to be nice looking. Think side walls of the tank or back of the tank that is exposed. You can do this with powdered tempura paints, black, brown, what ever. (Powdered colors will not speed the cure time.) You can also use acrylic, water base paint. Mixing a little water base paint into the polyurethane glue will cause the glue to cure much faster as PU glues require moisture to cure. (They normally get the moisture from the humidity in the air.) Spreading the glue over the face of the well cleaned glass will form a very good bonding surface for the foam to adhere to. (Personally I have not found the need for this, but it does work well.


There is one other reason that GS sometimes peels away from the wall. If it is sprayed on too thick, as it hardens, the outer shell of foam hardens first forming a barrier to the moisture that the foam needs to cure. That leaves uncured pockets of foam which do not harden and bond to the surface underneath. 

The simplest solution is to very lightly mist with water the base layer that the foam is being applied to, and then lightly mist the top of foam. This injection moisture quickens the curing time from days to hours, give the maximum expansion to the foam and strengthens the foam. 

Use water sparingly as it only takes 1 ounce of water to cure an entire can. Puddles of water will interfere with bonding to the surface. 



> 2) yes, that’s kinda how I built my last waterfall/stream. I foamed the pieces out of the tank, carved them out, and fit them into place.
> 
> 3) no..once the foam is spayed on, anything that comes in contact with it while still wet will become covered in sticky goo that’s impossible to remove..knives, blades, fingers, fabric. I would suggest using a little extra foam, letting it set over night, and then carve away what you don’t need. And wear gloves lol


Acetone will help clean up the sticky goo while it is still soft and gooy. Of note, I have read that acetone actually reacts with the carrier in the expanding foam, not the actual polyurethane itself, but it does help clean surfaces while the foam is soft. Note: The carrier / polyurethane elements of the foam will settle out and are why you have to shake the can periodically to ensure a good application. 


Once the foam cures nothing will take it off but time. (If the foam gets on clothing don't try and rub it off. Let if set up and then break it off. That way you aren't pushing the mixture into the fibers of the material.)

Also with PU foam it is a good idea to check the expiration date on the can as old cans can actually begin curing in the can. I have read studies on this and they found that storing cans upside down can slow this. 




> 4) yes, but you said it..the expanded foam won’t have medium in it and you’ll probably still have to cover it with more substrate
> 
> 5) natural fibers retain moisture better but eventually break down...though if it’s covered in plants then I guess it doesn’t matter? Tree fern fiber seems to be the best fiber background for moisture retention and getting plants to grab a hold better, imo. I’ve never tried clay but I hear it works great.


Good point.

Yes, you can bed all kinds of things into the foam, stone, sand, etc. 

Note: You can also use plastic grocery bags to mold and give texture to the foam, to give it a more rock like surface. Lightly mist the GS foam before covering with the grocery bags to speed setting. I talk about the process a lot in the article. 

By the way, I personally use a different kind of foam, a two part cartelized foam that does not use water to cure the reaction, but the principles are the same. I use the two part because I like to color my foam so as to create more natural colored rock without having to paint it.



> 6) my latest tank is a mix of coir, tree fern, eco-complete, and sand. Some parts are just coir and sand for a dryer area, some parts are all tree fern for a more moist area. The eco complete was added just for aesthetics. After drying, I pinned down dried Lfs with toothpicks to get vines to root on the back wall.
> 
> 7) yes, all the wall pots have good drainage..holes in the bottom and a layer of lava rock. With high humidity, the roots may rot if they’re not allowed to breath or dry out.


Excellent advice.

Personally, if I were using spay foam, I would only use the colored foam. Black is common. It is used for ponds and waterfall features.

I have seen one site that offered a brown.


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## HawpScotch (Oct 4, 2018)

Molding foam is a sticky mess. I spray foam, make it a little bigger than I want, let it cure and THEN take a blade to it cutting the shape I want little piece by little piece. Then apply a layer of silicone mixed with various things depending on where in the tank it is. For in tank streams I like using tiny river pebbles. Some fall off overtime but not enough to ruin the look.

I always build in tank. I imagine building outside the tank and then putting in just wouldn't give the same fit or seal. But I have no science behind that thought just intuition. 

Definitely want holes in your wall pots. Though each time I build a tank I seem to go less wall cups, more orchids/epiphytes.

One thing I strongly recommend. Get the pump outside the tank. A bucket beneath will suffice, a refugium is better if you plan to have aquatic creatures. It allows you to prevent and troubleshoot a number of problems associated with water features MUCH easier. Here's a photo I took today of a 'berried' cherry shrimp in the pond in my paludarium. Expecting babies anyday


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## thenerdwithin (Mar 10, 2019)

I'll add a background coating method that I haven't seen mentioned on this thread yet (you might find it elsewhere on the forum if you search). You can mix coconut coir with Titebond III wood glue and glop it directly onto your foam or other background material. Much easier than spreading silicone and applying a substrate of some kind on top, IMO, and it looks great!

Others might be better able to comment on its long-term durability but I've had it in a viv for 15 months now and haven't noticed any deterioration The glue is waterproof but not meant for use below the waterline. I included a small water feature but used silicone instead for those sections.

You may need to play with it a bit to get the right ratio of glue to coconut coir. In my experience you're going for a relatively stiff consistency without too much moisture. If that ratio is off you can get a bit of glue runoff as it dries. This happened to me and caused a pretty big mess in my false bottom that was difficult to clean up, but shouldn't be an issue if you're doing your background outside of the tank, or just put newspaper or something underneath it to catch any runoff. Just another option to consider!


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