rosco Posted January 20, 2005 Share Posted January 20, 2005 Hi all, As some of you are aware I have recently setup a fish room and to reduce my maintenance. I plan to get existing 3 2x18x18 tanks drilled and added to my system. Now canberra being the back water that it is, I have only managed to find one mob willing to drill these tanks (the other guy priced himself out of the market 2 and half times more than these guys). But the problem is that he only has 2 drill bits a 25mm and a 50mm bit. The existing tanks (2 6 footers) have an what I think is a an odd size hole already drilled (when I measured it 45MM diameter ) which reduced the pipe size to 32mm I think. So should I go for the smaller hole (which will reduce the pipe to 19mm, this maybe a bit small from previous threads) or go for a bigger hole 50mm (which I suspect will reduce the pipe down to 40mm) but that could be too big. I am a very new at this kind of filtration as I have only used cannister and air driven filters before so I really don't know what I am talking about so any help will be greatly appreciated. cheers Rosco Link to comment Share on other sites More sharing options...
WAZ Posted January 20, 2005 Share Posted January 20, 2005 Hi Rosco Get the tanks drilled with the 50mm holes (due to price) Then fit 40mm bulkhead fittings to the tanks - flanges on the bulkheads will take up the space. Inside the bulkhead fitting (on the outside of the tank) simply use a 40mm x 32 mm PVC reducer and glue in the 32mm PVC pipe. HTH. WAZ. Link to comment Share on other sites More sharing options...
rosco Posted January 20, 2005 Author Share Posted January 20, 2005 Done and Done thanks Waz. It is good know plumbing type people Link to comment Share on other sites More sharing options...
discusdude Posted January 20, 2005 Share Posted January 20, 2005 I would go for 25mm. I have a 25mm drilled in my 6*2*2 ft tank. The sump pump i have is rated at 4000 LPH. I have no problems, 25mm is heaps. 50mm is a pretty massive hole, 25mm bulkheads and PVC pipe is cheaper. Link to comment Share on other sites More sharing options...
trofius Posted January 20, 2005 Share Posted January 20, 2005 remeber it is easy to slow the amount of water leaving a tank but difficult to speed up! Link to comment Share on other sites More sharing options...
CThompson Posted January 20, 2005 Share Posted January 20, 2005 Your hole size should be dictated by your pump size (matching that is). However, if you drill a bigger sized hole, there is no issue in plumbing it down, as Wazz suggested. In fact it is an advantage to do so as if you ever upgrade you pump it will be much easier to put a bigger tank outlet/bulk head fitting than have the tank redrilled. Purchase your plumbing fitting from an irrigation outlet, up here I use Brooks Irrigation, but you must have other irrigation outlets down there. The size you want is the size of your pumps outlet pipe. Craig Link to comment Share on other sites More sharing options...
rosco Posted January 20, 2005 Author Share Posted January 20, 2005 thanks for the replies I have a reasonable sized pump (6000lph at ground level) so I might bigger hole and plumb it down. I have found an irrigation place that sells bluckheads for around $10-12 each for 40mm as opposed to $9 for the 25mm so I will go for that option. And I will be putting some form of flow regulator on the inlets. cheers Rosco Link to comment Share on other sites More sharing options...
discusdude Posted January 21, 2005 Share Posted January 21, 2005 Hey, In regards to the above posts, the tanks are 2x18x18. Realistically is there ever going to be a need for 50mm holes? Unless you are planning on having more than 5000lph pumping through the tanks? Link to comment Share on other sites More sharing options...
rosco Posted January 21, 2005 Author Share Posted January 21, 2005 Unless you are planning on having more than 5000lph pumping through the tanks? Discusdude and all, There will be 5 tanks on the system 2 x 6x2x18 and 3 2x18x18 the 6 foot tanks are already drilled and have 32mm outlet pipes If I go for the 25 mm holes won't I will have 19mm pipes coming out and joining the 32mm system. I am actually trying to get the system reasonable uniform in that I wanted to 32mm outlet pvc pipes, with plastic tubing for the input. My preference is to get the holes drilled at 40mm with 32 mm outets but what can you do? Also I assume that you mean 5000lph through the system. I expect that my 6000lph pump will be close to delivering that king of output even though it has to rise a metre and half (probably reduces to 4500lph it does not say on the pump). So what kind of problems will occur if I have smaller outlets in a high output system. It was my understanding that the amount of water leaving the system is directly proportional to the amount of water input. And I was going to have valve controls on the input tubing to regulate the flow. Is this correct? Sorry for all the questions but I have gotten all confused again so could someone enlighten me some of the finer points of system building cheers Rosco Link to comment Share on other sites More sharing options...
CThompson Posted January 21, 2005 Share Posted January 21, 2005 What you want to avoid is having a smaller diameter pipe than what is on the outlet side of your pump (you also want to match the inlet side of the pump as well). The reason for this is that it has been designed to pump at its maximum output with that size outlet. If you put a smaller pipe size to that, it will still try and pump its maximum amount out, but already it will have its job cut out for it due to it not being able to get the volume through a smaller pipe because of added friction. When it empties into the various different tanks, you don’t want the full volume of water from the pump going into the first tank, and I think you suggested, you were intending to put taps before each tank opening, which is the correct way to go. In effect, this means the actual plumbing feeding off the main line to each individual tank does not need to have a diameter to match the pump’s outlet. But how do you work out the exact size required? There will be too many variable to take into account. So, for my way of thinking it is simpler to just stay with the same size pipe diameter as what the pump’s outlet dictates, and put a tap on each one to regulate the water’s entry into each individual tank. You still don’t want back pressure on the pump, so one of these taps (the last one in line probably) should be let full open, then closed down according the volume being pumped out in the other tanks. That probably didn’t make much sense, but it will be easy to understand once your fiddling around with it. If you have a 6000lph pump, you’ll probably find its output at various different heads (height from the pump) written on the box, or other paperwork that came with the pump, so you will able to work out the amount of water it will pump dictated by the highest point. You will also loose water pressure with every bend in the pipe, and every tap due to turbulence, and the longer the pipe is, the less water will be pumped, there is nothing you can do about this other than try and limit the length and the amount of bends you need in your plumbing by efficient planning. The amount of water leaving the system is directly proportional to the water output, to the very drop, however that doesn’t mean the total amount of water the pump can move but the total amount of water the pump can move minus pressure loss from pipe friction, head, bends, taps and anything else that can slow you water’s passage to the tanks. I had someone suggest to me the idea of pumping water straight to a larger enclosed pipe above the height of all the tanks, with all the plumbing fittings coming out the bottom of this larger pipe. That way the pump had to have enough head to make that first height (which it has to do anyway), then all the water going to the tanks from this larger pipe, would be gravity assisted. This idea would work I think, but I don’t know if at the end of the day more water would get to back to the sump this way or through just plumbing the tanks straight from the pump. I think what you need to keep in mind Rosco, is to make sure all your plumbing fittings are not smaller than the outlet of the pump, and that they match the outlet pumps size (that is not bigger). That will keep things nice and simple, and won’t be wrong to the extent you will not loose water pressure due to poor planing In regards to the holes you drill to your tank, make sure once again that they are not smaller than the pumps outlet (you’ll be putting tapes on each one to regulate the flow) as this keeps the whole thing simpler as well. If you want to have the holes drilled at a larger size than the pump’s outlet, and plumb it down, that I think is a better idea, as it will allow for easier expansion at a later date, even 15 years down the track when you have dismantled your current set up, and are putting tanks into a different rack, with a possible larger volume pump, and you want to reuse you “old” tanks. Make sure your sump is larger enough to take all the runoff water when the system is turned off, such as during a black-out, or maintenance. You do this by calculating where you have had the tanks plumbed and where the lowest point is (inlet or outlet) as this is the height the water will drain to. You then add the water from each tank to get a total. So if you have a tank that is a meter by a meter by a meter, and the lowest point of plumbing is say 5cm. 100 by 100 by 5 divided by 1000 will give you 50 litres of runoff for each tank. If you have four tanks, then you will need to have a sump size that can take an extra 200 litres of water in addition to what it carries when being run. I hope I haven’t confused you more, but the sump size is very relevant, though a separate decision from the plumbing, but both are connected in the finished job, and both need to be taken into consideration in the planning stages. Craig Link to comment Share on other sites More sharing options...
rosco Posted January 21, 2005 Author Share Posted January 21, 2005 Thanks Craig for that great answer that has cleared up things up alot I had picked up bits and pieces along the way but that brought it all together. I will have to and check what fittings came with the pump and I will make plans from there. I think the sump will be big enough it is 3x18x17 that I Laurie and Shell help build for me. I think it will be fine . cheers and thanks Rosco. Edited to change from Chris to Craig I am really good with name aren't I who am I again Link to comment Share on other sites More sharing options...
BaZ Posted January 21, 2005 Share Posted January 21, 2005 Thanks Chris for that great answer Who's Chris? Link to comment Share on other sites More sharing options...
rosco Posted January 21, 2005 Author Share Posted January 21, 2005 Thanks for that Baz, DUHH sorry Craig ( Chris is my brother) cheers Rosco Link to comment Share on other sites More sharing options...
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