CREATION Of TOO FULL WITHOUT BORING the AQUARIUM.

Version 1.1 of the 30/03/98

By David Excoffier

 

Updates in Blue

 

The data correspond to a vat of 200L 100*l40*H50

This system functions since the 05/10/97 without problem.

It ensures a flow of 500L/H between the aquarium and the decantation (uneven: 1,25 m)

 

The main issue which one encounters at the time of the purchase of an aquarium is that very often it is not bored to allow the installation of a lower vat of decantation. Admittedly there exists in the trade of the effective systems (at TUNZE in particular) but their prices appear rather prohibitory, the economies that you will be able to make on this kind of apparatus could be invested in more critical equipment (Scummer, alive stones, etc).

 

Material:

- Tube 12/16, tube with air.

- Plexiglass 3mm or more (50*50) 60 FF.

- Food Tube PVC Internal diameter 32 mm, personally I used flexible tube of garden (can be not food!).

- small plastic vat (L23*l14*H14) 30 FF, to choose it highest possible.

- 1 tube of adhesive silicone.

 

Installation:

The system is very simple.

1- To cut out a Plexiglass band (l14 * H45), the height of this band corresponds to the water level which you want to have in the aquarium, to think of the thickness of the ground ice during your calculations, bevel the angles of the plates which must press on the bottom of the aquarium so as to marry the already existing joints. This band will be stuck in a tight way (silicone) in one of the corners of the aquarium (That makes a triangle seen of top).

CAUTION: check the sealing of the assembly well because if water can return elsewhere than by the top, it is draining assured the aquarium on the ground.

To cut out the Plexiglass, mark it with a cutter (several times) then break it, I use a mini drilling machine of model maker with a mini circular saw to mark the Plexiglass.

When the level of the vat will go up above the plexi, water will flow over.

To put a grid on the high part (fish).

 

2- To bore the bottom of the mini vat of a diameter equivalent to the tube of descent (40 mm external), to bore a circle I used a compass, then I made several holes with a mini drilling machine. To sandpaper the hollowed out part, as well as the face of the small vat intended has to be stuck on the rear window of the aquarium.

Note: sandpapering must be coarse for a good adherence of the adhesive, to clean the parts sandpapered with water (dust), the plastic of the small vats splits very quickly, put silicone on the possible cracks.

 

3- To stick the mini vat on the face postpones (or with dimensions) aquarium close to the angle stopped by the Plexiglass.

I recommend to you to put much silicone and to let dry the time necessary (at least 24:00)

The top of the small vat must be with the same height as the higher edge of the aquarium (it is not the case at home, it is 2cm in lower part because the mini vat is not very high).

 

Diagram 1

 

4- To place the large discharge pipe in the hole of the small vat so that it exceeds at least 2cm has interior this one, to make an enormous joint of silicone inside and by safety outside (to maintain the pipe in place during joining I used rings of electrician: ZIP).

Caution: not too much not to make exceed the pipe, because it is the difference between the top of this pipe and the top of the Plexiglass plate which will make it possible to have a flow.

In light plus the difference will be large, plus the flow will be high.

5- To cut out 2 pieces of pipe 12/16 a sufficient length so that they penetrate deeply in the overflow of the aquarium (approximately 10cm of the bottom) and that their other end is able in the mini vat, in lower part top of the tube of too full and with 1cm of the bottom of the mini vat (to envisage 2 suction cups to hold them in place). The two pipes are exactly the same ones and it is for a question of flow/safety that I put two of them.

 

6- To fill the aquarium, the too full one and the mini vat (to the large pipe), to start the 2 pipes.

With this intention I use a pump placed in the aquarium, I connect the end of the pipe which must go in the mini vat to the pump. Once the full pipe, I stop it with the inch and I position it in the mini vat on his suction cup. The end of the pipe must be always in water if not there is a risk of draining.

 

7- To fill the vat under the aquarium and to start the pump of increase.

 

The system acts like a siphon while trying to maintain constant the too full level of the part and the top of the discharge pipe thus more the top of this pipe is low more you have flow.

 

Diagram 2

 

This system keeps the advantages of a bored vat (air/water contact).

I tested another system with only one pipe of large diameter (cf aquamag I believe) but the permanent noise of water hunting rejected me.

 

Reduction of noise pollutions:

The initial version described above presents the sound disadvantages of a too full standard of bored vat.

Thanks to some councils which follow you will be able to reduce these harmful effects completely, only the noise of the pump of increase is audible in my current assembly.

 

To make penetrate the tube of descent entirely in the small vat, this removes a large part of the noises on the level of the lower vat, but moves the harmful effects at the entry of the tube of descent in the mini vat.

To place glass (standard glass has whisky) turned over in the mini vat above the entry of the water descent.

This glass is supported by Plexiglass holds so as not to touch the bottom and to thus allow a flow of water.

 

Caution: It is imperatively necessary to connect the interior part of glass, with the surrounding air to avoid the phenomena of pumping, to stick for this purpose a pipe to air connecting the interior of glass outside (cf Schéma 3). For the larger installations it will certainly be necessary to increase the number of pipes.

 

Diagram 3

 

SAFETY:

- the floating pump must be placed in manner that it pumps air (enough high) before making overflow the aquarium if the system breaks down.

- the pipe of return in the aquarium must be above water surface, not to trap the vat in the decantation if the pump of increase breaks down.

- At the time of the setting in water of many bubbles of air will invade the vat, to check for this period that there is not in tubes 12/16.

- The length of pipes 12/16 can be reduced so as to trap only one certain height of water to the case or the Plexiglass would break, attention all the same because the water which flows in the too full one creates many bubbles which it is not to better aspire with the 12/16 (long-term draining).

- The higher edge of the mini vat must be with the same height or higher than the top of the aquarium, if the large pipe stops the heights of the aquarium and of the mini vat equalize themselves without overflow.

 

IMPROVEMENTS:

There - To envisage too full the largest so as to be able to place a pump of starting, and also to easily recover the fish which could jump inside (to envisage a grid).

- To perhaps try to put a mini interior vat at the place of the Plexiglass, in my opinion that goes as well and it is less risky.

- For the larger installations (higher flow), to multiply the number of tubes 12/16 and to try to have the greatest difference in possible height between the level of the aquarium and the top of the tube of descent.

 

THEORETICAL AIR FLOW OF the SYSTEM:

A little physics to calculate theoretical output of the assembly, we do will see then that the real flow is much less low.

Thank you which have me, on fr.sci.divers, pointed out those that Bernouilli had in its time already reflected has this problem.

 

Thus let us pose some variables:

 

That is to say:

H: the difference between the two heights of water.

mv: density in kg/m3 (There is no difference between 1000 and 1035 for our calculation).

D: the diameter in meters of the pipe.

U: The speed of water in m/s.

S: the section of our tube (S = PI*d2/4), we can round pi with 3,1416.

DP: difference in pressure (DP = mv*g*h) with g=9,81 (revolved terrestrial)

D: Flow sought in m3/s

 

To facilitate the work of Fabrice, we will say that Sqrt term indicates the square root

 

- Calculation of U:

U = Sqrt (2*DP/mv)

- Calculation of D:

D = U*s

 

One thus obtains

D = Sqrt (2*mv*g*h/mv) * S

D = Sqrt (2*mv*g*h/mv) * PI*d2/4

The value G being telling:

D = Sqrt (2*g) * Sqrt (H) * PI/4 * d2

Of or:

D = 3,478 * d2 * Sqrt (H)

 

And finally here thus the formula in Liters per hour with D in mm and H in cm (Ouf E):

 

D=1,2524 * d2 * Sqrt (H)

 

This formula thus gives 570 L/H for a tube of 12mm and a height of 10cm.

This flow is THEORETICAL, it takes into account the fluidity of the liquid neither the brake which the elbow of the tube represents, nor even of other factors that I am unaware of (resistance of the walls of the tube, E).

My assembly with 2 tubes gives an theoretical output of 2281L/H. It appears within sight of the tests which I could carry out that it is necessary to divide the theoretical value by 4 to have an actual value, think there absolutely.

If I still add a tube, I pass to 1283 L/H (5132/4), that seems to me still beaucoupÉ

Also let us note that the flow increases more quickly with a total diameter higher than with a larger height (D is squared):

Made tests with two basins, a pump and tubes to see which is the number of tubes necessary and add in one or two per security measure.

Lastly, better is worth to use several small tubes than only one of large diameter (starting, sécuritéÉ).

 

 

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