Acrylic/Glass thickness calculator

[rclippi]

The good news is technology has come a long way in recent years so you are spoilt for choice. The bad news is there is a lot to choose from. Suggest you look at swim pool companies and information as most pools have viewing panels now.

I built a large concrete tank (circa 100,000L) with steel and glass viewing panes (2m water depth). Choose the right recipe of concrete. Very dense mix (42Mpa+) which is waterproof, with crystalline additive (waterproof) and painted membrane (waterproof). The tank design becomes more important once you have decided how to build. Formwork type is another huge discussion area. On your desired depth, I would use bottom drains, self cleaning circulation, rounded corners, a back or side drop internal filter so you can use airlifts. (Pump driven water will emulsify soft solids making water clarity harder and operating costs higher). Look towards koi pond concepts for tank design.

If you use a steel frame to hold your glass/acrylic panes you will strengthen the build, reduce the pane thickness, reduce the overlap required and minimise concrete edge chips. As well as reducing blind spots around the viewing panes that fish will gravitate towards. If you do use a steel frame, make that part of the concrete pour so you don't need to fasten and waterproof the steel to concrete. If your fussy, you can design a frame that sits flush with the inside concrete wall so fish don't scrape and injure themselves.

I would not recommend acrylic but it's a personal choice. Acrylic is more flexible so you need thicker to stop bowing. Or smaller size panels which is your personal choice. Glass technology is constantly improving. Tempered glass, with hydroscopic laminates was my choice. You can have triple or quadruple laminate on thinner glass to achieve overall thickness if cost is a concern. Some laminates (interlayers) are better suited than others but easy to waterproof the edges if using a steel frame.

Since we are discussing structural considerations, don't underestimate the compression pressure wave a large fish can generate in a bigger tank. A large pacu zooming up to glass then rapidly turning can easily create pressure much higher than 2m water depth.

If this is your dream tank, don't let costs ruin the overall effect and lifetime of pleasure you seek. Similarly, have another look at your dimensions to decide if it's really big enough.

YouTube has some nice concrete aquarium builds.

Do you have images of your amazing build?

 

[fishdance]

I've replied to your PM.
Happy to provide build advice and photos of my tanks by email if you don't share publicly.

 

[Zazikato]

I've replied to your PM.
Happy to provide build advice and photos of my tanks by email if you don't share publicly.

Hi there, I am very interested in your build and it seem so hard to find info on the internet regarding cement aquarium build and laminated glass panel do you mind showing me your build or giving out more info please? I am looking to build 600x200x200cm tank around the room which will be 3 viewing glass window

 

[fishdance]

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Hi there, I am very interested in your build and it seem so hard to find info on the internet regarding cement aquarium build and laminated glass panel do you mind showing me your build or giving out more info please? I am looking to build 600x200x200cm tank around the room which will be 3 viewing glass window

Hello Zazikato,

Glass is sold by it's area so the price of a 10m x 2m sheet is the same price as 4 pieces of 2.5m x 2m sheets. However for a first time DIY built tank, having several smaller sheets allows more flex along the tank length and is simpler - cheaper logistics for transport and installation. Allowing for more flex means you can use thinner and less precise constructed steel frames, less accurate in placement and construction techniques. This was my first large DIY built tank (10m x 4m x 2m deep) but now I have the experience and confidence to build with much larger panels and I am tempted to recommend you use a single panel of 6m x 2m if that appeals to you? It comes down to your comfort level. There are a lot of details but essentially this is a big simple water proof box with some clear panels on one side.

A couple of tips:

Plan your tank backwards.

* So think about how you would install the glass in terms of access, method, materials etc. In my case I bought a vertical lift grabber and used a franna crane so I designed my tank structurally to have clear access from above and planned a staged construction in sequence - installing the roof and insulation last. The minor difficulty is that the steel frame and glass sheets needed to be crane lifted into place blind as the crane driver couldn't see through the back wall but a good operator is used to that.

* The filtration needs to be considered before the tank, especially if built in. Bottom drainage, water jets in walls, aeration etc.

* The cure time on adhesive for viewing panels should be considered for larger areas. A neutral cure silicone allows several days, PU adhesives can adhere to itself after cure, etc. If cure time is a factor, start at the top of a panel where the cold join seam has the lowest water pressure, use a powered applicator (or several). Don't push the glass in too hard as it will spring back sucking in air. In fact, you will need a higher density seat arrangement so the glass can't ever touch the steel.

* There is far too much to cover for a concrete built tank, wall thickness, concrete recipe, admixes, steel, density. Your foundation including soil type (and tests) will dictate your minimum requirements.

* Water proofing the steel frame is relatively easy but very important. I installed magnesium sacrificial anodes additionally.

* Glass laminates generally don't like water and can de-laminate unless you water proof the glass edge - which should be protected against physical knocks anyway. SGP by dupont interlayer is the strongest and most high moisture resistant at this point in time but there is quite a bit in glass technology with constant improvements. My panels are 2.5m long x 2m high x 60mm thick and weight approx 500 kg each (from memory). However a single person can slide them sideways on a lubricated rubber seat for fine positioning.

A couple of photos below but I have deliberately not shared many. Unfortunately this forum is no longer the place for big fish and big tanks. There isn't even a large tank sub-section and the large tank owners with their invaluable information and experience all drift away as this is simply another general aquarium forum. Some of the hard core pond and koi forums will be useful. Installing viewing panels into ponds and swim pools is normal now.


You can private message me with your email address if you need extra help or photos as I don't visit here much.

Best of luck.










And of course, expect that things will never go to plan.

The steel frame was massively over engineered but despite this only weighted a couple of tonne.

When the steel frame was getting installed, the flat bed truck crane got bogged so a 15T crane was called to rescue however this got stuck too so a 25T crane arrived which also got stuck. Having three bogged cranes in my backyard was not fun. Heavy vehicle haulage rescure was required.