Overflow

[fishkeeprian]

Hi How do I work out the overflow to return capacity?

[bnumair]

Overflow in my opinion should be able to handle 1.5 times the return pumps capacity after head loss.

So for example if your return pump can deliver 3000gph then your overflow drains should be able to handle atleast 4000 to 4500 gph.
Different pvc pipe sizes handle different amount of flow. 1" drain can do max 960gph gravity fed.

[fishkeeprian]

Originally Posted by bnumair

Overflow in my opinion should be able to handle 1.5 times the return pumps capacity after head loss.

So for example if your return pump can deliver 3000gph then your overflow drains should be able to handle atleast 4000 to 4500 gph.
Different pvc pipe sizes handle different amount of flow. 1" drain can do max 960gph gravity fed.

Does my weir box control how many gallons an hour is pulled from my tank into the sump, or is this down to the size of drain hole? And the weir box is purley for pulling the water from the top? And is drain hole size based around your return pump and its rating?
My return pump is rated at 1000 litres per hour so I would do 1000 x 1.5 =1,500 L/H so I would require a drain sized of 25mm to achieve enough drainage so I anm geeting a constant stream of water around the tank, without the pump drying out???
The tank is 135L plus 65L SUMP so a total of 200litres total water volume I have not taken into account rock sand etc, is a 1000 L/H pump enough?

Thanks Ian

[fishkeeprian]

Originally Posted by fishkeeprian

Does my weir box control how many gallons an hour is pulled from my tank into the sump, or is this down to the size of drain hole? And the weir box is purley for pulling the water from the top? And is drain hole size based around your return pump and its rating?
My return pump is rated at 1000lph.

Thanks Ian

[fishkeeprian]

come on all those people who have built tanks can't help?

[bnumair]

Box itself should also be rated for specific amount of water for it to let through. If the teeth are close to each other or spaces are wide between the teeth matters in how much flow it will allow.
You do have to keep that in consideration as for example if the box itself only allows 500 gph and u have a drain and pump setup for 1000gph. Your pump is pushing twice as much water up into tank. You will over the tank unless dial pump down halfway. It wouldn't matter if drain is capable of handling 1000gph.

From your info so far I see your pump is pushing 265 gal per hour (1000l/h) so you need a drain that can handle 400 gph.
1/2" pvc drains 420 gph (1/2" = 13mm)
3/4" drains 660 gph (3/4" = 20mm)

Find out the flow rate of you box? But honestly unless it's a very small box with very fine teeth with very little space between, you should be fine.

[Kevin Guthrie]

If the drain isn't big enough to handle the volume from the pump, your tank probably overflows before the pump runs dry. And before it overflows your weir gets overtopped and become superfluous. The weir pulls surface water as you say (assuming the surface currents are not fighting it) and the teeth keep large objects from going in and jamming the return piping.

25mm inside diameter pipe should work. Note a 25mm hole is not big enough for a 25 mm ID pipe.

[fishkeeprian]

Originally Posted by bnumair

Box itself should also be rated for specific amount of water for it to let through. If the teeth are close to each other or spaces are wide between the teeth matters in how much flow it will allow.
You do have to keep that in consideration as for example if the box itself only allows 500 gph and u have a drain and pump setup for 1000gph. Your pump is pushing twice as much water up into tank. You will over the tank unless dial pump down halfway. It wouldn't matter if drain is capable of handling 1000gph.

From your info so far I see your pump is pushing 265 gal per hour (1000l/h) so you need a drain that can handle 400 gph.
1/2" pvc drains 420 gph (1/2" = 13mm)
3/4" drains 660 gph (3/4" = 20mm)

Find out the flow rate of you box? But honestly unless it's a very small box with very fine teeth with very little space between, you should be fine.

Hi I am thinking of doing 10 x the volume of water in my tank, which when readind to seems to be the norm regarding pumps and wave makers. So If I do 10 x 200 = 2000LPH return pump (This calculation doesnt not take into account loss of volume through rock, sandbed and equipment). What size pipe work is required?

[bnumair]

2000 lph = 528 gph.
So if you want to push 528 gph from your return then u need to have followings:

1. Return pump that can deliver 528 gph after however many feet above its delivering. (Head loss)
1/2" (13mm) pvc with a pump can push 840 gph.(3175l)
3/4" (20mm) can push 1410 gph.(5300l)

2. Now that you are pushing say 550 gph you need a box that can handle about 800 gph (3000l).

3. Drain pipe needs to be 1"(25mm) which is capable of draining 960 gph (3600l)

4. Hole for a 1" bulkhead will be slightly bigger than 1" a and is dependent of what make/brand bulkhead you get.

[bnumair]

What size tank do u have?

[fishkeeprian]

Originally Posted by bnumair

What size tank do u have?

Hi thanks for all your info the tank size 90 x 42 x40cm. How do i know if my over flow can handle that volume?

Thanks

[bnumair]

6 3/8" L x 2 3/8" W x 3 5/8" H (Nano tank) 250gph
5 1/4" L x 3 5/8" W x 5 1/4"H (Up to 60 gallon tank) 500gph
7 1/4" L x 4" W x 5 1/4" H (Up to 120 gallon tank) 900gph
12 1/2" L x 4" W x 5 1/4" H (Up to 200 gallon tank) 1200gph
18 5/8" x 4" W x 5 1/4" H (Up to 300 gallon tank) 1600gph

[fishkeeprian]

Originally Posted by bnumair

6 3/8" L x 2 3/8" W x 3 5/8" H (Nano tank) 250gph
5 1/4" L x 3 5/8" W x 5 1/4"H (Up to 60 gallon tank) 500gph
7 1/4" L x 4" W x 5 1/4" H (Up to 120 gallon tank) 900gph
12 1/2" L x 4" W x 5 1/4" H (Up to 200 gallon tank) 1200gph
18 5/8" x 4" W x 5 1/4" H (Up to 300 gallon tank) 1600gph

Hi bnumair,

So what are these dims for?

[bnumair]

Those are dimensions of the overflow box. Compare that to the closest size that you have and you will know how much it will drain.

[fishkeeprian]

Originally Posted by bnumair

Those are dimensions of the overflow box. Compare that to the closest size that you have and you will know how much it will drain.

Thanks are the numbers at the side amount of teeth on the overflow?

[fishkeeprian]

My over flow is L= 23cm x W=10cm x H=36.5cm. It is a corner unit, the side has 7 slotted teeth which are L= 0.5 x H= 3.5cm with a gap of 0.5cm between each tooth. The front panel has 8 teeth and has same dims as side panel. How many litres LPH would this make my overflow?

[bnumair]

from your description its rated anywhere from 900gph to 1200gph. (3400l to 4500l)

[fishkeeprian]

so if i want to do a turn over of 2000LPH this would be ok? or is this not enough because of the size of overflow?

So I can get cracking can you help me out with the following;

Size of drain hole required (what i need to drill)?

Size of Bulk head required?

Size of pipe to suit Bulk Head?

Size of return hole?

Thanks Ian

[bnumair]

Originally Posted by fishkeeprian

so if i want to do a turn over of 2000LPH this would be ok? or is this not enough because of the size of overflow?
its fine you can do that
So I can get cracking can you help me out with the following;

Size of drain hole required (what i need to drill)?
hole size is dependent on what brand of bulkhead u buy, check the hole size from manufacturer

Size of Bulk head required?
for drain you need 1"(25mm) bulkhead

Size of pipe to suit Bulk Head?
1" bulkhead will take 1" pvc (25mm) pipe for drain.

Size of return hole?
i would do a 3/4" return bulkhead with 3/4" pipe(20mm)
Thanks Ian

[fishkeeprian]

Thanks. The tank already has a bottom bulk head fitted 1" . The inside diameter is 25mm. Its fitted in the bottom so i am going to do the dorso drain setup. the nut that goes over the end is approx 30mm so will i get a 25mm pipe to screw on?

Also the other end of the bulk head has a female out put so it will only except a 15mm scew in piece to get my water into sump?

Thanks