what do I need once I get the holes drilled in my tank?
- Thread starter tim000
- Start date
Depends on your setup, sit down and lay everything out so you can *see* what is going to happen...i.e. the sump is connected to your pump to you your tank return..etc.
Then think about what gpm you are returning to the tank from your sump, my guess is you'll probably have a 1/2" return line and 3/4" drain or smaller.
Most bulkhead fittings are 1-3/4" outside diameter with a variable inside diameter, to fit whatever siphon diameter you need 1/2, 3/4, 1, etc. Usually your LFS will have bulkheads in supply, if not try a specialty plumbing store, I haven't had much luck with your average Home Depot carrying them.
Most of all take the time to *see* what you are doing before you start drilling. I made the mistake of drilling a 2" hole and I had to specialty order a 2" O.D. bulkhead with a 1" I.D. fitting, which wasted time and money. But you need to understand how the bends are going to effect the head loss on the pump and how that corresponds to your total system circulation.
Then think about what gpm you are returning to the tank from your sump, my guess is you'll probably have a 1/2" return line and 3/4" drain or smaller.
Most bulkhead fittings are 1-3/4" outside diameter with a variable inside diameter, to fit whatever siphon diameter you need 1/2, 3/4, 1, etc. Usually your LFS will have bulkheads in supply, if not try a specialty plumbing store, I haven't had much luck with your average Home Depot carrying them.
Most of all take the time to *see* what you are doing before you start drilling. I made the mistake of drilling a 2" hole and I had to specialty order a 2" O.D. bulkhead with a 1" I.D. fitting, which wasted time and money. But you need to understand how the bends are going to effect the head loss on the pump and how that corresponds to your total system circulation.
If you drill the bottom of your tank (1) make sure the bottom isn't tempered glass (cannot drill tempered glass) (2) how are you going keep your level in your tank and not flood sump (overflow box, riser pipe. PS stay away from check valves they always fail! I think the easiest is to drill is the back of the tank as high up as you can on each side. Have say a 3/4" pump return and 1" or 1 1/2" overflow bulkheads.
so what your saying is to have to holes up top? so then I wouldnt need to have a piece of plexiglass in the corner would I?
and I am having a glass shop drill them for me, they would know if it was tempered right?
and do u know of any sites that have a drawing of this method?
thanks alot!
[ October 31, 2001: Message edited by: tim000 ]</p>
and I am having a glass shop drill them for me, they would know if it was tempered right?
and do u know of any sites that have a drawing of this method?
thanks alot!
[ October 31, 2001: Message edited by: tim000 ]</p>
Lower price tanks use tempered glass on the bottom because they can use thinner glass and is cheaper to make. The backs aren't useally tempered. At least I haven't seen any and I'm a old fart, hehe. Yes you don't have to have a box at all. The only draw back is the tank will have to be about 4" to 6" from the wall so you can 90 down. This way you will have more room inside you tank for stuff. Most newer tanks will be marked tempered do not drill but is not always the case. Its hard to tell if glass is tempered or not, But the back on a 30g I'm 99% sure it isn't tempered.
DO NOT drill the holes near the top!
The problem with holes at the top is that it severly limits the rate the tank will drain at. The reason for this is that you need a little bit of head pressure to get the flow going.
The water needs to cascade over the edge of the overflow to ensure the surface water (the best bit to skim) does in fact leave the tank. For this the drain holes need to be lower than the level of the water could be with no overflow.
In terms of the overflow I prefer to just glue a piece of glass in the corner between the hole and the rest of the tank. The actual water level will be a little bit higher than the height of the overflow - the extent to which depends on how quickly the water is returning to the tank from the sump.
Another appraoch is to have a stand pipe. This might be better on a small tank as it uses the least space.
A good way to check that you overflow does not leak is to fill the tank to the top of the overflow and then leave it - if you have water in the overflow after - a few minutes, or a few hours then you are leaking....
You want to make sure the tank can drain as fast as you are filling - no matter how strong your return pump is. You can always add a second drain hole, but it's so much easier to get a bigger hole in the first place. I advocate using a hole that is clearly bigger than you possibly need.
I prefer a hole at about half height - that way if the overflow fails (which will never happen - but just in case) the tank will not completely drain onto the floor - the fish are going to survive.
The advantage of a bulkhead fitting is that it's very secure. The disadvantage is that the inside diameter though the hole is smaller than the inside diameter of a pipe that will just fit in the hole, so using a bulkhead reduces the maximum flow. You can use silicone to glue the pipe in place although this isn't ideal if you plan to move the tank anytime soon. If you're going to use a standpipe then a bulkhead is a must (for mechanical strength).
The problem with holes at the top is that it severly limits the rate the tank will drain at. The reason for this is that you need a little bit of head pressure to get the flow going.
The water needs to cascade over the edge of the overflow to ensure the surface water (the best bit to skim) does in fact leave the tank. For this the drain holes need to be lower than the level of the water could be with no overflow.
In terms of the overflow I prefer to just glue a piece of glass in the corner between the hole and the rest of the tank. The actual water level will be a little bit higher than the height of the overflow - the extent to which depends on how quickly the water is returning to the tank from the sump.
Another appraoch is to have a stand pipe. This might be better on a small tank as it uses the least space.
A good way to check that you overflow does not leak is to fill the tank to the top of the overflow and then leave it - if you have water in the overflow after - a few minutes, or a few hours then you are leaking....
You want to make sure the tank can drain as fast as you are filling - no matter how strong your return pump is. You can always add a second drain hole, but it's so much easier to get a bigger hole in the first place. I advocate using a hole that is clearly bigger than you possibly need.
I prefer a hole at about half height - that way if the overflow fails (which will never happen - but just in case) the tank will not completely drain onto the floor - the fish are going to survive.
The advantage of a bulkhead fitting is that it's very secure. The disadvantage is that the inside diameter though the hole is smaller than the inside diameter of a pipe that will just fit in the hole, so using a bulkhead reduces the maximum flow. You can use silicone to glue the pipe in place although this isn't ideal if you plan to move the tank anytime soon. If you're going to use a standpipe then a bulkhead is a must (for mechanical strength).
A couple more thoughts:
Buy your bulkheads first so you can get the holes drilled the correct size. I like 3/4" pump return but 1/2" is good on small tanks and get a larger for the return to sump so you know you have enough to keep from overflowing say 1 or 1 1/2"
On the pump return on the inside of tank you can use modular pipe classie looking or a regular pvc 90 tip...use Rit black dye to dye pvc black looks nice specially if you spray paint the tank back flat black.
Buy your bulkheads first so you can get the holes drilled the correct size. I like 3/4" pump return but 1/2" is good on small tanks and get a larger for the return to sump so you know you have enough to keep from overflowing say 1 or 1 1/2"
On the pump return on the inside of tank you can use modular pipe classie looking or a regular pvc 90 tip...use Rit black dye to dye pvc black looks nice specially if you spray paint the tank back flat black.
man this is so confusing.
I just dont know what to do for my 35g. I like the idea so far about drilling 2 holes on the back of the tank below the water line, would this is the best thing for me or should I stick with the corner over system (which I know nothing about).
if anybody has any pics of eith of these please send them my way!
thanks alot for helping me so far, im still confused though
if anybody has any pics of eith of these please send them my way!
thanks alot for helping me so far, im still confused though
What you do is on the inside you put a 90 up and a strainner on top . This way you have the advantage of adjusting the water level where you need it. The strainers can be bought at www.aquaticeco.com....Done it this way many times. Get your plumbing first so you know where to drill the return to the sump and have enough room for the 90 inside the tank.
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