Useful Tips and Conversion Tables
Here we have assembled some tips of wisdom on sizing your piping and
fittings. You will find conversion tables, dimension tables
and friction loss tables. We are always looking for useful
information to help others with their plumbing needs, so e-mail us
any tips or tricks
you have. Good luck with your aquarium and we hope this page helps
you.
Tip #1:
When sizing your plumbing, consider the friction loss in pipe table
listed below. You want to ensure that you don't buy fittings,
valves and piping larger than you need because that will cost you
money
you don't need to spend. On the other hand, if you size them
too small, you will have so much friction in the plumbing that you
will
not get even close to the rated flow from your pump! The pump
loss curve is an inverse square, so a little bit of friction drops
your
pumps flow by the square of the amount of friction you added.
Tip #2:
When you get a pump, look at the inlet and outlet connection sizes.
Generally, most pumps have an outlet connection smaller than its
inlet
connection. This is so the pump can use velocity pressure relationships
to its advantage.
If you are going to pipe the water more than 2-3 feet from the pump
back into the tank, it is advised that you step up the piping to the
same size as the inlet, or one size larger. Consider the friction
loss in pipe table. So, within the first 9" or so after you
come out of the pump, you will want to transition up to that larger
pipe size. This tip will get you the best possible flow from any
given pump. It should save you from buying a larger pump because
of bad plumbing :)
Always keep the inlet piping to the pump equal to or greater than
the inlet size of the pump. If you use smaller piping coming into the
pump than the pumps inlet then you will significantly shorten the life
of your pump!
Tip #3:
When using a gate valve to throttle flow locate a utility ball valve
after the gate valve. This will allow you to quickly turn off
the flow through the gate valve without changing its setting.
This can save you many hours when you have pains-takingly balanced two
opposing gate valves for your skimmer and tank return off the same pump!
Tip #4:
Place unions and utility ball valves on both sides of your pump.
(Or, use true union ball valves on each side.) This way you can
turn off the pump, shut the ball valves, and then remove the pump from
your system for its monthly impeller cleaning. The advantage of
the true union ball valves is that they take up less space than the
other combination and they are usually about the same price as buying
a separate union and valve.
Tip #5:
Don't use tools with serated jaws to tighten threaded plastic joints.
The serated edge of the tools jaws creates indentations with sharp edges.
These indentations cause stress cracks that lead to leaks and plastic
plumbing ruptures. Try using a strap wrench, or placing a piece of leather
or thick rubber between the tool and the plastic fitting/pipe. I can't
count how many times I have seen wet floors because someone did not
know this tip. Please let us know if you have any questions or need
some suggestions.
Tip #6:
When choosing a check valve remember that check valves are designed
to prevent flow reversal. Not to guarentee that there will be no reverse
fluid flow at all. There are special check valve assemblies that do
guarentee that there will be no reverse fluid flow, but they are very
expensive and are usually used in drinking water systems to prevent
contamination. In an aquarium environment, the need is to prevent reverse
fluid flow during maintenance and power outages. For this purpose the
best check valves are diaphragm or piston check type valves. These valves
will provide the best possible revese fluid flow protection available
in a reasonable price range. Keep in mind that there most likely will
be a very small amount of leakage past a check valve in an aquarium
application. This leakage will be on the order of a few drops per minute
or even none when a good quality check valve is used.
Tip #7:
If you use a fluidized bed filter on your aquarium, you can run into
trouble if a power outage occurs. During a power outage the fluidized
bed filter will be starved of oxygen and will start to produce acid.
If your power outage was more than a few minutes, it is advised, that
you flush the filter before using it on your tank. One way to flush
the filter is to fill a buck with aquarium water and have the filter
pull water from the bucket and return to the bucket for a while. This
will flush the acid from the filter and reoxygenate the filter. It works
best if you go through at least two buckets of water before reusing
the filter.
Tip #8:
This one a fellow I used to work with taught me. If you ever need to
bend PVC piping try this. Almost fill the piece to be bent with ordaniry
sand. Leave about two inches of unfilled length; more if it is going
to be a very tight bend. Plug both ends with wooden stoppers that are
lightly seated with a hammer. Pre-heat your oven to 200 degrees F. (Note:
During pre-heating the oven temperature can exceed 500 degrees F depending
on your oven so you must pre-heat the oven before using it.) Lay the
pipe on a piece of foil or a metal sheet and put it in the oven. Heat
it until the pipe starts to soften. Carefully remove the pipe with hot
pads or heavy leather gloves as it will burn you. Then slowly bend the
pipe around a wooden mold to the desired shape. Clamp or block in place
and allow to cool slowly. You can then empty the sand, trim up the piece
and wash it. The sand keeps the pipe from collapsing during the operation,
but you will probably still seem some reduction in cross sectional area
when you bend the pipe. Now you know how the pros shape piping.
Tip #9:
Always use a screen on the inlet piping to your pump. Chunks going
through your pump will damage the impeller and shorten the pumps
life. If you are using a bulkhead fitting to pull water from your
tank or sump then get one with a screen on it.
Plastic PVC Pipe Dimensions
|
Nominal
Size Inches |
Actual
O.D. Inches |
Schedule
40
|
Schedule
80
|
Wall
Thickness Inches |
Weight
Lbs/Foot |
Wall
Thickness Inches |
Weight
Lbs/Foot |
1/4" |
0.540 |
---
|
--- |
0.119 |
0.10 |
1/2" |
0.840 |
0.109 |
0.16 |
0.147 |
0.21 |
3/4" |
1.050 |
0.113 |
0.22 |
0.154 |
0.28 |
1" |
1.315 |
0.133 |
0.32 |
0.179 |
0.40 |
1
1/4" |
1.660 |
0.140 |
0.43 |
0.191 |
0.57 |
1
1/2" |
1.990 |
0.145 |
0.52 |
0.200 |
0.69 |
2" |
2.375 |
0.154 |
0.70 |
0.218 |
0.95 |
Friction Loss in PVC Pipe
|
Flow
GPM
|
Feet
of Head Loss per 100 Feet @ Diameter (Inches)
|
1/2" |
3/4" |
1" |
1
1/4" |
1
1/2" |
2" |
0.5 |
0.3 |
--- |
--- |
--- |
--- |
--- |
1 |
1.1 |
--- |
--- |
--- |
--- |
--- |
2 |
4.1 |
1.0 |
0.3 |
--- |
--- |
--- |
3 |
8.6 |
2.2 |
0.7 |
--- |
--- |
--- |
4 |
14.8 |
3.7 |
1.1 |
0.3 |
--- |
--- |
5 |
22.2 |
5.7 |
1.7 |
0.5 |
--- |
--- |
10 |
80.5 |
20.4 |
6.3 |
1.7 |
0.8 |
0.2 |
15 |
--- |
43.3 |
13.4 |
3.5 |
1.6 |
0.5 |
20 |
--- |
73.5 |
22.8 |
6.0 |
2.8 |
0.8 |
30 |
--- |
--- |
48.1 |
12.7 |
6.0 |
1.8 |
40 |
--- |
--- |
82.0 |
21.6 |
10.2 |
3.0 |
50 |
--- |
--- |
--- |
32.6 |
15.4 |
4.6 |
60 |
--- |
--- |
--- |
45.6 |
21.6 |
6.4 |
70 |
--- |
--- |
--- |
--- |
28.7 |
8.5 |
80 |
--- |
--- |
--- |
--- |
36.8 |
10.9 |
90 |
--- |
--- |
--- |
--- |
45.7 |
13.6 |
100 |
--- |
--- |
--- |
--- |
56.6 |
16.5 |
Example:
30 feet of 1" diameter PVC pipe carrying 20 gpm will produce:
(30 x 22.8)/100=6.84 feet of head loss due to just the total length
of pipe used in this system. Then you must still add in the
elevation change, and the loss due to all the fittings and valves. |
PVC Fitting Friction Loss in Equivalent
Feet of Pipe
|
Fitting
Size |
90°
Elbow |
90°
Street
Elbow |
45°
Elbow |
45°
Street
Elbow |
Out
side
of Tee |
Straight
thru Tee |
1/2" |
1.6 |
2.5 |
0.8 |
1.3 |
3.0 |
1.0 |
3/4" |
2.0 |
3.2 |
0.9 |
1.6 |
4.0 |
1.4 |
1" |
2.6 |
4.1 |
1.3 |
2.1 |
5.0 |
1.7 |
1-1/2" |
4.0 |
6.3 |
2.1 |
3.4 |
8.0 |
2.6 |
2" |
5.0 |
8.2 |
2.6 |
4.5 |
10.0 |
3.3 |
Example:
If you have three 1" - 90° elbows in your piping system, you
are introducing: (3 elbows x 2.6 feet) = 7.8 feet of equivelant
pipe. Add this length to the total length of your system,
and use the previous table to figure out the amount of head loss
introduced by the new total system length. |
Conversion Factors for Units of Pressure
and Head
|
(Multiply
unit on left by factor in column.)
|
Pounds
per square inch |
Pounds
per square foot |
Feet
in height of fresh water |
Feet
in height of salt water |
Pounds
per square inch |
1.000 |
144.000 |
2.3067 |
2.2504 |
Pounds
per square foot |
0.006945 |
1.000 |
0.01563 |
0.01563 |
Feet
in height of fresh water |
0.4335 |
62.428 |
1.000 |
0.9756 |
Feet
in height of salt water |
0.4443 |
63.9887 |
1.0250 |
1.000 |
Example:
To convert from 10 feet in height of salt water to pounds per square
inch use the cross table above as: 10 ft x 0.4443 psi = 4.443
pounds per square inch. |
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