Thanks for all the replies!.
So understand correctly, I should calculate how much water there must be in the SC to allow the volume of water to be emptied in 5 minutes or more, therefore the water will be resting in the SC for 5 minutes.
Filtration retention time = Filtration volume/Discharge rate into pond
That is for individual chamber or total filtration volume.
Therefore for a 1000l SC and water to rest for 5 minutes the pump must not empty the SC in less than 5 minutes, with some math this is a 12000 l/h pump rate will empty the chamber in 5 minutes, therefore I should look into a pump of sy 10,000 l/h with a pond volume of approx 20,000 l this means the pump will then cycle the water in the pond around once every 2 hours.
So for a pump that has capacity of 12000 l/h deduct friction losses, let's say U remain with 11000l/h
5m= V filtration/ 11000l/h
Vf=( 5 * 11000)/60= 55000/60= 9100liters....approximate that to 1000 liters
That U have to have if U don't use any settling additions.
For the medicating bypass I am not sure what to bypass? Could you please clarify.
There are some medicines that harm your bio filter, like PP, and some other...that kill your bacteria. So U need to bypass only your bio filter.
For head losses the pipes will be 400mm below the surface, therefore the level of water should drop radically before the pump will run dry.
I am also going to build a pond soon. So I decided to put my pipes in the filter in such a way, that I can avoid that from happening, by using the endless river principle of the erick filter...
The flow in the filter becomes horizontal and not diagonal, like in up and down filter.
The overflow into the SC is an excellent suggestion - I will add one definatly.
U need to calculate the flow of your weir...and remember in this case U will need to add automatic top up in the pond...something in the principle of toilet cistern...but for water tanks.
Water level in the pond is known to drop....so this way U can maintain your weir functioning all the time.
you can calculate the discharge or the height of the water spilling over a given weir length with many formulas.
A popular formula is Francis formula for the discharge of a sharp-crested rectangular weir having a length b greater than 3h is
Q= discharge over weir, ft3/s (m3/s)
b= length of weir, ft (m)
h= vertical distance from level of crest of weir to water surface at point unaffected by weir drawdown (head on weir), ft (m)
n= number of end contractions (0, 1, or 2)
h0= head of velocity of approach
If the sides of the weir are coincident with the sides of the approach channel, the weir is considered to be suppressed, and n=0. If both sides of the weir are far enough removed from the sides of the approach channel to permit free lateral approach of water, the weir is considered to be contracted, and n= 2. If one side is suppressed and one is contracted, n=1.
Or use the easy one….Horizontal, sharp edged weirs (Bazins formula)
Q = 0.66 x cB x (2g)0.66 x H1.5
Q = water flow rate, m3/sec
B = width of the weir, metres*
c = discharge coefficient, average 0.62
g = gravitational constant, 9.81
H = Height of the water over the weir, measured behind the weir edge, m
Here you can do the calculations [You must be registered and logged in to see this link.]
your discharge in the weir will depend on: Size of your pond (the difference in head between KP pond free surface water level and the drop of the weir crest free fall surface water level),area of weir discharge(L.H),and the discharge of your pumps.
On the returns, I actually thought of that yesterday All there will be in the corner next to the last chamber on top of each other.
I have never heard of Sound Pipes? could you please tell me more?
Sorry about sound pipes...it is stand pipes.
Airlift pump, I actually have a good industrial strength blower. I will research a bit and see if I can build a test airlift to lift water from my swimming pool hehe, If that works - you propably just saved me allot of money in buying a pump! Will let you guys also know how the expiriment is going hehe.
Blowers don't have the pressure needed for operating in depth, U are better off with a air pump...since if your filter is 1m deep, U will need to make the chamber for the airlift much deeper.
U will never regret going with the airlift option...it will save U more than R1000 a month in electricity. So make provision for both when building your pond, pump and air lift....and research the subject well.
Now most people are going with that option, if they want to economize...
I really appreciate all these suggestions, I will only get to build this pond once so if I can get it right first time that will make me plenty happy!
U need to have a look at a pipe settler...fantastic for a settlement chamber. Last year I saw some panels at the show, used for cooling towers, like a block looks like bee hive....I saw someone in Jbg using it as bio, but the real function for it is...settling chamber.
What happens is as the particles travel they conglomerate, and drop down the slop do the pipe. It allows U to reduce the size of your SC.
Another thing I would advise U to do is automate your pond...it will not cost much, but U will appreciate it in the long run....and easy way to do that is use air lifts on a timer...good for U but even better for your fish
Have an excellent day!
U are welcome. Glad to be of some help.