Mbuna Posted November 6, 2011 Share Posted November 6, 2011 Hi all, was looking for recommendations on where to drill a hole for my bulkhead on a 6x2x2 tank. I want to drill the side of the tank and dont know how far down from the top to go. I have done a fair bit of looking around on he net to no avail - all i could find was "about an inch below your waterline". But wouldnt the size of the return pump play a factor in this? The hole will be 50mm to accommodate a 40mm bulkhead and the return pump will be 4500lph so i cant see a 4500lph pump keeping the waterline an inch or so above a 40mm bulkhead?any thoughts?CheersHarry Link to comment Share on other sites More sharing options...
Brisbane Fish Junkie Posted November 6, 2011 Share Posted November 6, 2011 First I unscrew the bulkhead and use the rubber seal. I put it inside upto the rail as high as it will go mark it top and bottom then transferthe marks outside then using the rubber i mark the holeIf you want to mark the side like this and your tank has no side rails. I would use a scrap piece of glass or anything that fits that is straightremember to - 10mm or your rail size because you have marked from the top of the front and back railI also feel 4500 is a little overkill for one 6x2x2 tankBFJ Link to comment Share on other sites More sharing options...
joller Posted November 7, 2011 Share Posted November 7, 2011 i have a 3500L/h on a 4x2x2, i drilled my holes too high so i had to put a valve on the return to limit the speed, my 2 overflow bulkheads are 25mm thoughwhat you can do is...buy a $10 plastic tub from go-lodrill holes in the tub, one hole close to the top and drill one hole close to the bottomfit the bulkheads and hook it up to your pump so that the return is the higher oneput your tub somewhere so that the return is the same hight above the sump waterlevel that it would be when the setup is finishedput some water in and turn it onthen once you've done all that measure the water height above the bulkhead you'll have a good approximate Link to comment Share on other sites More sharing options...
shelly Posted November 7, 2011 Share Posted November 7, 2011 Mate if possible a hole in the base of your tank is a better option for your outtake and you can adjust the water level by reducing/increasing the pipe length. You get better flow and no airlocking doing it this way. If you have to use the side as you outtake you can still adjust the height with a bit of clever plumbing. If you cant work it out I can take a pic of mine to show you how it works as it is hard to explain. HTH Aaron Link to comment Share on other sites More sharing options...
Aquaholic Posted November 7, 2011 Share Posted November 7, 2011 You could use a smaller pump. I have 2 - 3x2x2 plumbed together with a sump pumping over 2 m high with a 3500 pump and I have to back it off a bit. Work out where you want your waterline to be and then work out where the strainer will sit and the centre of that is where you drill. Back drilled tanks work fine. Use a T fitting with a cap that you can drill a hole through or take off if you need more airflow. I use mine without caps. Link to comment Share on other sites More sharing options...
Mbuna Posted November 7, 2011 Author Share Posted November 7, 2011 thanks for the responses guys! had visitors this arvo so didnt get a chance to drill the tank...BFJ - i was using the same pump to run two 3x2x2's with 32mm bulkheads and it seemed to have a good turnover, i was actually using the 40mm bulkheads on this tank because i would like to get a larger output pump in the future i do like good turnover. I like the idea of using the rubber seal as a template, this tank does have siderails.Joller - what height did you have your overflows?Aaron - i have a funny feeling the bottom of the tank is tempered so dont really want to risk it, also i didnt really want a weir in the tank- i find them a little distracting. please post some pics though, id love to see your design works.cheersHarry Link to comment Share on other sites More sharing options...
Aquaholic Posted November 7, 2011 Share Posted November 7, 2011 Another option. Drill a hole in a thin piece of wood. Put the fitting on and hold it against the end of the tank, work out the height etc. Link to comment Share on other sites More sharing options...
Mbuna Posted November 7, 2011 Author Share Posted November 7, 2011 Aquaholic, what size bulkheads do you have? my 3x2's seemed to cope with the 4500lph pump with the same head height (approx. 2m). maybe they overestimated my pumps output? Link to comment Share on other sites More sharing options...
Aquaholic Posted November 7, 2011 Share Posted November 7, 2011 25mm (clear poly pipe) and mine's pumping around 2.5m. You could always use two drain holes. Link to comment Share on other sites More sharing options...
Mbuna Posted November 7, 2011 Author Share Posted November 7, 2011 You could always use two drain holesvery true Link to comment Share on other sites More sharing options...
Saroon Posted November 7, 2011 Share Posted November 7, 2011 My 4ft tank was already drilled when i bought it, two 1' 1/4' bulkheads to sump and one 3/4' bulkhead return. Still dont know what i am going to do with the plumbing just yet, still working it out Link to comment Share on other sites More sharing options...
Aquaholic Posted November 7, 2011 Share Posted November 7, 2011 My system was made by Absolute in Newcastle. They make nice tanks and its a great setup. Link to comment Share on other sites More sharing options...
joller Posted November 7, 2011 Share Posted November 7, 2011 Joller - what height did you have your overflows?i put them as high as they could possibly go Link to comment Share on other sites More sharing options...
Mbuna Posted November 8, 2011 Author Share Posted November 8, 2011 allrighty, hole drilled... no cracks...all good. ended up going 10mm down from the max height the bulkhead would allow. i was planning on placing another bulkhead 1/3 of the way down to accommodate a gate valve for quik waterchanges, would this weaken the glass to the point that it would crack?cheersHarry Link to comment Share on other sites More sharing options...
Brisbane Fish Junkie Posted November 8, 2011 Share Posted November 8, 2011 allrighty, hole drilled... no cracks...all good. ended up going 10mm down from the max height the bulkhead would allow. i was planning on placing another bulkhead 1/3 of the way down to accommodate a gate valve for quik waterchanges, would this weaken the glass to the point that it would crack?cheersHarryNot on 10mm hand tight is enough or if it's going to be hard to reachI add quarter turn with grips Had 6mm crack cause I over tightened a bulkhead glass got hot Few weeks after I'd done it didn't help it's painted black and near the Shed wall but that's the only one and I've fitted 100+BFJ Link to comment Share on other sites More sharing options...
CThompson Posted November 10, 2011 Share Posted November 10, 2011 I also like a lot of water flow, and so do the fish. The "depth" of the hole drilled into the side of the tank can be adjusted with an elbow fitted between the bulkhead and the strainer. Raise it or lower it, and you raise or drop the height of the water leaving the tank. Not a good idea to throttle the pumps return flow as I think somebody mentioned, if for no other reason than you are paying for that water no longer being pumped, and also you are making the pump work harder.Hole size I hope was at least equal to the pump's inlet/outlet. I like to drill the next size up in fact, fit it with the larger bulkhead but plumb it down on both sides to match the pumps return pipe size. That way if I ever upsize the pump and it has bigger plumbing requirements, the drilled hole will not act as a bottle neck when the plumbing through it is increased to match the bulkhead size.When you tighten the bulkhead; I put a bit of silicone between the rubber gaskets, and tighten by hand then with multigrips just "nip it" up a touch more. Link to comment Share on other sites More sharing options...
Mbuna Posted November 13, 2011 Author Share Posted November 13, 2011 got the tank up and running today with alot of fine tuning with the overflow, mainly trying to silence it using some tubing on the external overflow t-peice. was getting alot of back pressure but have got around that-for now. ill try to get some pics up soon. Link to comment Share on other sites More sharing options...
joller Posted November 13, 2011 Share Posted November 13, 2011 the pump doesnt work harder its always running as hard as its made to run, but yes it is a waste of the potential Link to comment Share on other sites More sharing options...
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