Hi,

First Instructable here so be patient and I'll be grateful for any feedback and advice :).

In this Instructrable I'm going to advise on how to fit an aquarium background suitable for tropical fish. The pictures throughout are of my own tank which I made 2 years ago and have kept fish (successfully - meaning alive) in for 2 years including 1 crayfish, 2 plecs, 3 red-finned sharks, guppies and tetras (to name a few), prior to moving house and hence tank.

Have fun :D

PS. sorry about vague costing, most of the materials were free since I work in construction.

Step 1: Inspiration

When I first started looking at backgrounds I did a lot of looking about at different styles and peoples methods as well as asking pet stores what they would advise or how they had made theirs. This gave me a much better idea on what to look for, how to design and the cost involved.

Most pet stores will sell ready made backgrounds made from moulds and already decorated. This might be a better option for a lot of people but I went ahead and made my own; i) because I like it, ii) because I could design it how I wanted and to the shape of my tank, iii) because I had access pretty much everything I needed for free.

Step 2: Preparing Your Tank

1) Buy or use an already owned fish tank, make sure (especially if your buying 2nd hand like me) that the tank is water tight and fully suitable otherwise you might end up wasting a lot of time to find a crack in the glass etc when you fill it up.

2) Once you have the tank measure its dimensions (taking into account any lips, eg. for lids to sit on).Then buy and cut a sheet of insulation board down to size.

I used 'kingspan' insulation board, stripped the shiny foil off it and thinned it out. This was due to accessibility, other foam boards which are cheaper can generally be used and it will eventually all be sealed anyway. Just a precaution though polystyrene is very hard to work with and can become very messy, a denser more workable foam board is advised.

3) Make sure the board fits fairly snug to the floor and sides (again depending on your design, mine is relatively plain compared to those shown earlier in the previous step. If you are going for a more complex design you still need the board but just cut the pieces individually and piece them together to create your design.

* Kingspan TW55 Thermawall Features:
Board size 1200mm x 2400mm x12mm = £12.60 from http://www.building-supplies-online.co.uk/kingspan...

* 2nd Hand fish tanks (depending on the contents) can vary widely in price but will be much cheaper than buying new and a lot less valuable if anything goes wrong with a background - mine for example was £10 from a neighbour however I did have to clean the existing contents out including a few dead fish :(

Just as a rough guide to cost.

Step 3: Design Time

This was by far the best (but messiest) stage in my books.

1) Once fitted, take you board out of the tank and in pen/pencil (depends how confident you are of your first design) draw onto the outer face of the foam marking out channels, rock faces etc. trying to keep the initial layout relatively simple as you can always add extra details later on.

2) Once fully happy with the overall layout begin carving out the foam. As you can see in the pictures the major areas were kept as rocks and all the in-between areas were the valleys/gaps. Whilst carving out your design you can also add extra detail/texture to your background. Again this depends on your design and the style you're looking for as slate rock would have smooth flat faces whereas a coral effect would be highly textured and lumpy. As always this goes back to your initial research and planning, expressing its importance before you start anything especially if you are buying the materials.

As you may have noticed, during the carving my board snapped. Luckily it wasn't too detrimental for me but it would have been worth cutting in myself to minimise damage. Therefore for easier carving and re-fitting later on, depending on the size of your tank/design it might be worth cutting the bard into more easily manageable sections.

4) As you continue carving out you can add more details into your design that you may have thought of before or as a spur of the moment creative aspect. I added a few little holes/caves into a few of the larger rocks for fishes to hide in or to allow for plants.

* This stage shouldn't cost anything (maybe the expense of a half-decent knife and a pen if you don't already have them), it just takes a while but is worth doing properly.

Step 4: Blow-torching?

1) Get yourself a blowtorch :D (a hot air gun should also work fine but nowhere near as fun)

2) Go over the carved face of the board relatively quickly - the aim is to get rid of loose material and generally smooth out/slightly seal the bard ready for the next step...not to turn what you've probably spend a couple of hours making into a small bubbling mound of nothing.

Make sue you are in a large spacious area (eg. your garden) where there is good ventilation so your not inhaling any gases given off

3) Once you've blow-torched the whole carved face, double check all the loose bits are gone with a soft brush and make sure any little caves etc. that you have incorporated into your design haven't been missed out.

4)Just as an extra in my design I places a few tubes out of the board and caved a line out to the side where I eventually created a boxing. These were initially designed in for filtration however didn't provide the filter with an adequate supply of water so were adapted with a air pump to create a hidden bubble supply :D

As mentioned planning is key but there will be things you think of as you progress, think them through and if they seem worthwhile and useful adapt away!

* A small blowtorch shouldn't cost more that £10 -http://www.gasproducts.co.uk/acatalog/GoSystem_GB2... I got mine for free luckily, but so far everything you will need should be sold at a DIY store and so far it should have cost less than £20 aside from your fish tank.

Step 5: Back to the Tank!

1) Make sure throughout that your board still fits the tank, especially at any breaks you have created, check that they fit together and that you design flows between them.

2) Use silicone to stick your board to the back and sides of your tank ensuring that it is watertight all the way around and especially between sections (if you have chosen to break the board up into manageable pieces). Don't skimp out at this stage, one tube of silicone should easily cover you and if in doubt put more in any gaps, the main aim being to keep the water in the visible part of your tank...not behind the background where it might go stale.

3) As shown keep the background pressed hard against the back of the tank (I used leftover pieces of board) and leave it to set for at least 24hours. Again don't skimp out, use the silicone thoroughly and everywhere in irregular patterns as shown just to ensure maximum coverage and adhesion for the background and make sure it is pressed back thoroughly (the silicone will squash as you can see)

Importantly, check regularly through this progress that no silicone has got on the rest of your tank as it can be awkward to remove and might leave a staining. If spotted soon enough it should just wipe off with a wet cloth.

Also you may have noticed in the pictures that the previously white board has been covered before sticking, this was just me experimenting and not being fully sure when I made it. It didn't help and made the board slightly less adhesive when installing, it also added more rigidity meaning it was harder to stick back into the tank. I would advise against it and wait for the next step :)

* Silicone is fairly cheap at £1-3 a tube and £1 for a cheap caulking gun (tool used to apply it) both of which again can be bought at most DIY or pound stores.

It is debated however whether or not to use proper aquarium silicon, I used bathroom grade and checked on the back whether it was harmful or not and I never had any problems or side effects with the fish. It's up to you if you would like to double check though so here is a useful link -http://www.thereeftank.com/forums/f45/100silicone-... It does come at a lot higher cost too but if you feel safer using it you can never be too careful when it comes to your fish :D

Step 6: Sealing the Background

I've used the same picture here as in the last step as you can see the right hand side has been more thoroughly covered/layered in it.

1) Mix cement and water together to make a runny paste (like thick gravy) it shouldn't be too watery and similarly not too thick but you should be able to brush it on so that it forms a coat on your background. Make sure again that you have covered the whole surface including any caves etc. including all of the silicon joints at the sides and in-between any pieces.

Cement can be coloured using different pigments (ensure they aren't toxic first though), this allows for greater adaptability in terms of design. Alternatively you can use pond sealant to cover any paints such as G4 Pond Paint, this is a slightly more expensive route but should take a lot less take and might be easier (I didn't so I can't vouch for it) again ask in decent non-chain pet stores especially larger ones with pond sections as the majority of them seem to have a good knowledge of the topic.

2) Coat and coat it. Allowing for at least 4 hours between each coat (depending on whether it is quick drying cement or not, mine wasn't so I allowed for 24hours), I used around 4 coats to ensure a proper coverage. Doing this also allows you to: i) put an initial base coat on, ii) Put another base coat on, iii) Start using pigments and adapt colouring such as darker areas in the channels/cracks of your design, iv) Finalise your colouring and provide it with a smooth final coat (slightly wetter). Also keep checking the coatings and if they seem to be drying out too quickly and cracking just keep the tank damp using a fine mist (use a cleaned out spray bottle)

This stage was the one where I did the most research as I was unsure about the effects of the cement on the fish, however I finally went ahead with it and with the next steps made sure it was fine before putting my fish anywhere near it. Once happy with it I introduces fish gradually and have had it running with no unexpected loss of fish or impure water quality for the last 2 years.

Again make sure between each coat that the concrete mix has not reached other areas of your tank, it can and will be messy so just ensure all of the glass not associated with your background is spec free from little or big splashes.

* Plain cement only costs around £4 / 10kg which should be more than enough - http://www.wickes.co.uk/Products/Building-Material... and a couple of cheap paint brushes shouldn't push this stage over £5 total (just make sure you don't have stray bristles in your background whilst covering it)

Step 7: Fill 'n' Empty

1) Once you have finished applying coats of cement paste and allowed them to dry give the background a thorough inspection making sure: i) All gaps around it are sealed, ii) All silicone is covered with cement paste, iii) there is no cracking and the background is smooth, iv) That the tank is clean and nicely presented around the edges of your background

2) Fill it up! (with water of course) check as your filling it that no waster is getting around to the sides/back of the background as this would be the best point to empty and re-seal and paint. If not then carry on right to the top. Allow the water to sit in the tank for 24 hours and then empty it out.

This stage again is best done somewhere nice and open on next to a grid where you can safely keep you tank whilst it's full.

3) Repeat stage 2 (I filled and emptied the tank a total of 10 times) this allows for the potentially harmful chemicals in the cement paint to seep out and be removed with the water changes. As I got to the end of this stage I began using test strips and taking water samples into local pet stores who provided free testing. The last refill was allowed to sit in the tank for a week before testing and it came out perfectly clear and suitable for aquatic life :D.

You may have noticed that I added a boxed off area to my background, this was a spur of the moment design change which a sincerely regret as it made everything more awkward and due to being a last minute change was not implemented properly. It was used for my filter/heater/air tubing connecting to the tubes I had installed in the background as mentioned earlier, however it didn't allow for thorough filtration of the bottom gravel which meant I had to to clean the tank more regularly. Next time I will probably do a similar sort of thing just better implement it and design it in rather than make do due a mistake.

Step 8: Voila!

Once you've made sure the water is clean and clear fill the tank back up and allow it to settle to an appropriate temperature. Whilst its settling add your gravel/substrate and any other ornaments/plants. You can the proceed to add your fish and enjoy a new cool looking tank!

As for me I'm back to the inspirational stage for my next tank hoping to make it more complex and better looking. Just for fun here also a picture of my crayfish 'Herbertos' enjoying the background which he loved to use as a climbing frame.

The total cost following each stage shouldn't be more than £30 depending on your material choices and design complexity

Have fun and I hope you find this guide useful :) Feedback will be highly appreciated on either the background and stages or just purely on how I've presented this Instructable, I'm just glad I've finally got around to making one.