SamH Posted October 18, 2009 Author Report Share Posted October 18, 2009 Could you pop up here and drill my tank please Suphew? :lol: I've been advised against getting it drilled, it was my first choice but now is not a likely option. I've watch several vids on YouTube of guys doing it without failure but I guess they're hardly going to post the video of them stuffing up and cracking the tank though. :-? Quote Link to comment Share on other sites More sharing options...
SamH Posted October 18, 2009 Author Report Share Posted October 18, 2009 Not sure if you drawing is to scale, but it looks like 3/4 of you tank is going to drain if the power goes off? The level of water in the tank will only drop to below the top of the pipe where the water goes in, won't it? :-? Quote Link to comment Share on other sites More sharing options...
Dimsum Posted October 18, 2009 Report Share Posted October 18, 2009 The level of water in the tank will only drop to below the top of the pipe where the water goes in, won't it? :-? SamH is right, only drops to the inlet, which is right up the top of the tank. It's the water in the overflow drops down to the 1/4 mark, but when the return restarts again it fills up and its all go. Quote Link to comment Share on other sites More sharing options...
Cricketman Posted October 18, 2009 Report Share Posted October 18, 2009 Cricketman: Would the pump not work against the flow of the water if it was on continuously? pump working in the same direction as waterflow ie, siphon running through the pump.... if you got 2 pumps actually running wth the same L/h then you wouldnt need the syphon or priming etc?? one pumping in (pulling from teh tank) and one pumping back up. or man up and drill it! Quote Link to comment Share on other sites More sharing options...
SamH Posted October 18, 2009 Author Report Share Posted October 18, 2009 or man up and drill it! If I drill it, will you replace the tank with a tank of equal or great volume/value? Quote Link to comment Share on other sites More sharing options...
Ira Posted October 18, 2009 Report Share Posted October 18, 2009 pump working in the same direction as waterflow ie, siphon running through the pump.... if you got 2 pumps actually running wth the same L/h then you wouldnt need the syphon or priming etc?? one pumping in (pulling from teh tank) and one pumping back up. Yes, if you magically manage to get a smaller pump working at a negative head pulling water from the tank into the sump perfectly matched with another larger pump working at a positive head pumping into the tank then they'll become the unmatched by about the 20th rotation of their impellers... It IS possible though to set up the sump so that it cannot overflow the main tank. Just put the pump in a seperate chamber that the water overflows into and have it sized(Or only fill it up to a given amount) so that it runs out of water before overflowing the main tank. Not ideal but most pumps aren't going to immediately burst into flame the instant they run dry. Easiest way to do it(And the way I did mine) plug the overflow and fill the main tank almost to overflowing. Then unplug the overflow. Wait until the water levels stabilize and mark the pump chamber. BTW, be ready to stop the water flowing into the sump if it's going to overflow it> Quote Link to comment Share on other sites More sharing options...
suphew Posted October 18, 2009 Report Share Posted October 18, 2009 The level of water in the tank will only drop to below the top of the pipe where the water goes in, won't it? :-? Yep, my mistake, thought the blue line through the pipe was the end of it. Quote Link to comment Share on other sites More sharing options...
suphew Posted October 18, 2009 Report Share Posted October 18, 2009 Could you pop up here and drill my tank please Suphew? :lol: I've been advised against getting it drilled, it was my first choice but now is not a likely option. I've watch several vids on YouTube of guys doing it without failure but I guess they're hardly going to post the video of them stuffing up and cracking the tank though. :-? I don't travel up your way as much as I used to otherwise I'd have a go at it. You might be able to convince me to lend you a drill bit though. How thick is the glass? Did they give you a reason for advising against drilling? I've drilled maybe 8-10 holes in tanks, and never had one break. Although they have always been thicker glass. Quote Link to comment Share on other sites More sharing options...
SamH Posted October 18, 2009 Author Report Share Posted October 18, 2009 It looks like 10mm to me. I wouldn't drill it, I don't trust my own drill let alone my skills. :oops: Quote Link to comment Share on other sites More sharing options...
SamH Posted October 19, 2009 Author Report Share Posted October 19, 2009 Is there a formula for working out the flow rate of the 20mm pipes? I'm looking at pumps, 600LPH is too small right? Quote Link to comment Share on other sites More sharing options...
Ira Posted October 19, 2009 Report Share Posted October 19, 2009 Is there a formula for working out the flow rate of the 20mm pipes? I'm looking at pumps, 600LPH is too small right? Yeah, that's probably way too small. A small return pump doesn't matter on an overflow setup. You don't get any more overflowing back to the sump than you're pumping up to begin with. But it's small because you'll be barely getting a trickle back into the main tank with a pump that small. Go for something more like 2000LPH. Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted October 19, 2009 Report Share Posted October 19, 2009 In a gravity system, if you double the diameter of the pipe you will get four times the flow. Quote Link to comment Share on other sites More sharing options...
suphew Posted October 21, 2009 Report Share Posted October 21, 2009 A 20mm pipe will flow about 1300lph. here is a site that has some useful information about this sort of stuff. http://dursostandpipes.com/ When you are looking at pumps you need to work out the approximate dynamic head height, personally to do this take the rough distance from the water line of the sump to the water line of the display, then add half again to allow for pipe work, taps, bends etc. Any good pump will have a 'flow curve', you look on the curve for the head height you have and it will tell you how much flow you'll get. Quote Link to comment Share on other sites More sharing options...
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