External tank design 8x4x4 feet

 Before moving into our new house last year, I had approximately a year to design and plan while waiting for the developer to finish their works. And part of my delirium, I've always wanted a nicely setup external pond, a sorta haven away from the noise and bustle, and craziness of life, a place of meditation, of the sounds of water gurgling away....but alas! Time and money did not allow, ah well! So, here were my designs that were drawn up using Google's Sketchup. A readily powerful tool, that any avid noob can easily pick up to draw their glorious dreams of grandiose. 

This fits my small lil' 8 by 4 feet piece of grass turf in my yard. It's to be at least 4 feet in depth, with an extra 2 feet for the filtration system. The idea for the filtration comes from our normal, aquarium tank overflow where filtration works because of the equilibrium in water pressure. Basic cement doesn't really work well in this setup as cement is only semi-waterproof. Mixing cement with waterproofing compounds will prevent it from being porous but not prevent it from cracking, which is always the fear in building cement ponds. The other suggestion is to look for sheets of rubber pond liner that you can lay into the tank. Pets Wonderland in Ikano sells them, but their biggest pieces were only 6 by 6 feet costing below RM100 though! Or maybe to paint over with a latex paint. The most durable and what most people do for koi pond is to fiberglass it in the end! Obviously this ends up doubling the price of your tank :( But it becomes more of a permanet setup then!

From the top view of the tank, you can see three sections, with 3 access pipes (for cleaning purposes). The last portion is suppose to be for filtered water, that is to be pumped back into the tank. And as you empty the last tank, water pressure will force whatever debrie from the tank, into the first section and thus the filtration works. 

The tank is actually sloping downwards towards the filter. This will allow whatever debris/dirt to collect at the bottom which will work something like a sump pit. This is then connected to the first of the filter section via an unground pipe. 

As you can see, the filter is left open as I was planning to make this sections out of glass. 2 big pieces and a whole lot of silicone to glue it to the cement works. I was told this works in construction, yet to try :)

The external pipe above is actual a water outlet pipe from the roof gutter! Originally, this ran underground and I thought this wouldn't be so fun as to have it burst under my tank setup! It'd be a major problem repairing it then. As such, i was planning to extend it above. This could be hid with plant growth or maybe some amount of woodworks. All access water will overflow out, through the main sewage line. Having the extra 3 access points allows for easier cleaning as all you'd have to do is to open the outlets, while stopping the water-flow from the main tank. Scrub clean washed throughly with an external access pipe makes life easier. But there's always the worry of th outlets leaking or bursting as this may actually drain your entire tank! Hence, the reason to have the outlet allevated at least 6 inches above with extra piping which you can then remove when you're cleaning!

One other thing to plan is to install and automatic refill system that will top up the tank whenever the water level drops below a certain level! Which sorta works like your normal flush toilets! At least that'd remove the hassle of topping up the tank ever so often! 

As you can see, this is just an experiment that never went into an actual development stage. It is also a work in progress. Lots of external stuffs are left off, like the filter pumps, the reverse waterline going back into the tank. The wooden cover which I did plan to get as having kids with these things in mind isn't practical if you can keep it covered at all times!

 As such, most of what I have here is base on best practises and what I've gotten from other people's pond design. So saying, do work with practicality and common sense yah if you were to use this! This sketchup can be downloaded from here! do let me know if you've actually made your pond, would love to see the end-result! Oh and yeah... anyone out there wanna sponsor my tank? :P