Browse Forums Eco Living Re: Buying a tank 2Nov 27, 2015 2:24 am 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Buying a tank 4Nov 29, 2015 1:59 pm oneJohn I could have separate detention and retention tanks. In that case do you just fill the retention tank, and the overflow from the retention tank goes into to the detention tank? Yes. oneJohn It would still have the same head issues, so I assume the benefit is just that the tanks are not as tall? The smaller tank's height will depend on the tank's diameter of course. The smaller tanks will be more manageable when locating and installing as well as providing more head if they are lower. oneJohn I prefer the idea of having leaf diverters at the downpipes, but if it's going to end up too problematic or costly, then we'll just go with a simple wet system with riser. The problem with standard wet systems is the amount of sediment that builds up in the below ground horizontal pipes due to the amount of dirt that collects on a house roof. This can lead to anaerobic conditions and blockages. You can overcome this by fitting a DIY sediment trap to a non turbulent section of horizontal pipe to trap and then flush bed load. This simple trap that I came up with a few years ago uses off the shelf parts and is easy to install. The trap is reduced in size and an inline tap is fitted to the end of the smaller pipe/hose and the trap flushed every few weeks or so. It is very effective. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ oneJohn In terms of the head with just the single tank, I may have been a little pessimistic. With a 2450mm diameter tank, if it only needs to fill to 9000L, that will rise to about 1900mm. That's 600mm below the eaves if the tank is on natural ground level, with maybe another 100mm if I alter the levels a bit. The Supadiverta's maximum head height is taken from the top of the internal reservoir wall that also doubles as the filter's support. The usual head loss between the gutter's sole and the top of the reservoir wall when the downpipe is first diverted under an eave is about 500mm as a minimum but a 550mm head loss is more usual. Some of this head loss is made up by the additional distance (head) between the tank's water level when full and the height of the water at the top of a vertical riser used in a common wet system. It must also be remembered that leaf diverters also reduce the amount of available hydraulic head but the Supadiverta is also fitted with a superior 750 micron internal filter. The difference in effective head loss between most commonly available leaf diverters and the Supadiverta is minimally in favour of the leaf diverter after the height difference between the top of the vertical riser and the height below the tank's overflow outlet is factored. Given that you need high volume inflow capacity to the detention tank during heavy rain, I think that your best choice would be to have a standard wet system and not the Supadiverta's syphonic variable flow system that is designed to harvest numerous downpipes but to also reduce the flow rate when the tank becomes full to prevent water tank overflow problems. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Buying a tank 5Dec 01, 2015 8:36 am I heard back from council, and they don't have any particular site discharge requirements. They don't even check it, although say it should be constructed according to the builder's plan's that went through council. That's just a standard wet system, so it favours going that way. Thanks for the extra detail. It sounds like I might just make it on head height with the supadiverta to fill the tank, but the inflow would be more limited as the tank level rises, meaning it doesn't work as well in its detention capacity. It's all compromises. I liked the idea with the supadiverta that any losses at the leaf diverter would go down the stormwater pipe, rather than spilling near the house footings - as we are on reactive soil. Thanks for letting us know. The programmer will have a look at this later today. 2 6692 DIY, Home Maintenance & Repair But if it is a ground level open pit, then it is not a charged system. No surprises there. The pipes have obviously been altered and there would be a reason for this.… 3 31284 If you can calculate the reasonable charged head from let's say 100mm below the gutter to the top of where the vertical riser's horizontal discharge pipe will be, that… 11 17539 |