Please help me with bulkheads / tank connectors

[Flobajob]

Hi,

I ordered my tank to be drilled with 2 1.5" holes for the weir and 2 1" holes for the returns. Then I realised that for bulkheads the hole has to be a fair bit bigger than the pipe size.

But then I measured the holes and they are bigger than I asked for - the weir holes are 45mm and the return holes are 28mm. I have tried looking up the hole size required for 1.5" bulkheads, and although they do not all say the same size, all the figures I have been given are larger than my hole size by a few mm.

Unfortunately I have already bought the 1.5" plumbing supplies and so I was wondering if there was any way to reduce the bulkhead OD to make it fit through the holes, or whether I should use 1.25" bulkheads and reducer coupling, or whether I should just go for 1.25" piping throughout.

Please advise me as to what I should do (I don't want to drill the holes out further BTW).

Many thanks for your help,

Flobajob.

 

[george1098]

a standard 1" bulkhead uses a 45 mm hole, I'm not sure what size 28 mm is for, but it is probably for a 3/4" or 1/2" bulkhead.
I wouldn't recomend modifyting your bulkheads to fit in the hole because you really don't want them to leak down the road. Can you return the plumbing parts you bought if worst came to worst?

and, I don't think you should totally rule out the idea of widening your holes. It's really not that hard to do with i diamond coated bit on a dremel, I've done it a million times with no problems. Just make sure you do your research (ask me) on how to do it and what to use before you try.

 

[Flobajob]

According to this I should be able to use 1.25" bulkheads for the drains. Do you think that the drain size will be enough for 500gph? Assuming it will, should I use the 1.5" pipe with coupling, or should I use 1.25" pipe throughout?

 

[george1098]

How many drain lines will you have?
with 2 drain lines your are more than ok with 1.25" piping, but if you have 1 drain line I would go for the 1.5" diameter. I have 1.5" drains with about the same amount of flow running through mine and there have not been any problems.
How big is your tank?

 

[Flobajob]

I have two drain lines (as already stated). My tank is 90 gallons, with a 30 gallon sump. I plan on using Herbie's method though, so I will only have one drain operating during normal use. I did check the drain calculator and it said I can get well over 700gph with a single 1.25" drain.

 

[george1098]

ok yes, you should be fine. Make sure you put a good guard over you drain lines so nothing can block the flow. I've avtually had an anenome get stuck in the drain line, luckely I had two running at the time.