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Important Media Considerations:
The following qualities are important considerations when buying internal plastic biological filtration materials (usually Polyethylene, or plastic, as it is generally referred to) :
the material should not trap dirt and debris. This includes pieces of food, algae, and any other free floating particulate matter.the material should allow good gaseous exchange by braking up the water in really fine streams and drops.
the material should have a relatively large surface area. You will need somewhere between 2 and 2.5 square feet of biological filtration area per gallon of water in the tank. The exact amount, whether the lower number or not, depends on the load in the tank. If the distribution of the water over the medium is really maximized, you can go as low as 1.25 square feet of surface area per gallon of water.
the material should be totally inert. No leachings whatsoever are allowed.
the material should maximize the utilization of the biological chamber. This means that there should not be large gaps between the individual media pieces.
the material should be permanent, meaning that it does not deteriorate, and thus never needs replacing.
the material should be unbreakable, so that no rods, or pieces, break off and ruin the pump impellers and volute, and possibly the inside of a chiller, if you were to use one (not part of a basic system of course).
it should not be too rough as that would result in dead bacteria being overgrown by live colonies, which is not desirable as it will lead to very small amounts of anaerobic activity underneath the live active layer, possibly killing some of the live layer of bacteria off, or reducing its potency due to anaerobic activity by-products (Thiel, 1988).
The controversy surrounding this topic has been going on for quite some time now. Very simply, it is my educated opinion, based on extensive testing, that drip plates perform better in trickle filters than spray bars do, because:
We, therefore, now recommend drip plates in trickle filters, and have, after trying many variations, arrived at the drip plate that we feel performs best:
You can modify an existing drip plate by plugging holes that are too close to the sides with aquarium silicone, and add holes if necessary. If the plate can be removed you can do so rather easily, if not, you must drill the plexiglass plate while leaving it where it is. Use only acrylic drill bits! They will prevent cracking of the acrylic when you drill through it. They are not expensive, and are sold at most stores that sell acrylic in custom cut sizes.
To position the holes correctly, draw lines with an acrylic scratching tool, 3/4" apart length wise, and 3/4" apart cross wise. Then drill holes where the lines cross (see drawing below).
To obtain tapered holes, use a small countersink drill bit after you have drilled the holes. This gives the tapered effect which will improve the flow of the water downwards into the biological chamber, and over distribute it better over the medium you are using.
Although the drip plate may not appear to you as a significant part of the trickle filter, it is a very important one. Indeed, by selecting the correct one, or modifying it as we suggested, you can ensure a much more even dispersion of the water coming down from the tank, over the medium that you are using.
That in itself assures a more efficient biological filtration and, ultimately, a greatly improved water quality, the purpose of using a trickle filter to begin with.
Retrofitting for a slanted bottom:
Most units on the market have a "flat" trickle filter bottom. As we have seen, this does not promote the forward moving of detritus and debris. Retrofitting an existing filter is not complicated at all:
Measure the inside dimensions of the sump very carefully. The match of the plate you will be adding, with the inside of the sump must be exact. Measure from the back of the filter, coming towards the front, up to where the biological chamber ends. The plate only needs to be long enough to fit underneath the biological chamber.Acquire the piece of acrylic from a plastic dealer in your area.
Place the plate in the sump in such a way that it slants forward at an angle of a few degrees only.
Dry the sides where you will need to glue properly. This is really important because glue does not stick if the sides are still moist. Go over the sides of the filter with paper towels several times.
Use aquarium silicone to glue the plate in place. Glue with care because you need a very good seal. No water can be allowed to get underneath the plate. It would stagnate and create anaerobic conditions.
Let dry for at least 75 minutes, preferably somewhat longer. Since not a great deal of pressure will be exerted on the seams you glued, you will not need a 24 hours curing period.
The force of the current over the slanted plate will now move the debris and detritus forward, and you will be able to syphon it out very easily. In the process you will prevent it from decaying in the system and reduce your dissolved oxygen levels.
Adding Compartments to the Sump:
Rather than buying canister filters to add certain water filtering products to your tank, you may wish to add compartments to hold these same compounds.
Included in this list of compounds are, for instance, X-nitrate, Poly Filters, molecular absorption discs, resins for chemical filtrations, and others.
Type 1:
Place the unit off the bottom of the filter by resting it on a ledge made of small blocks on all corners. For most efficient set up glue the corners onto the compartment. Use acrylic cement, or aquarium silicone. Place floss or screening on the bottom to prevent the material from getting through.
Type 2
No base (bottom).
The compartment rests on the bottom of the sump. Drill holes all around the base to let the water get out easily. Quarter inch holes usually will do. Remark : Clean the material regularly to prevent it from clogging and restricting the water flow.
Remember to change the material that you are using in these compartments on a regular basis. Most exhaust themselves as they do what they are meant to do. Follow the manufacturer's instructions in this respect.
If you do not attach (glue) the compartments permanently to the base of the sump, you will be able to remove them, and replace them with a larger (or smaller) one, should the need for that arise. Not attaching them will also simplify cleaning them, as all you will have to do is remove it (them). Always remove them very slowly, to prevent detritus trapped inside from getting into the sump of the trickle filter, and being sucked in by the pump(s).
Fittings on the trickle filter:
A good trickle filter should come equipped with all fittings needed to hook it up.
This includes a fitting a the top, a hook-up for airline tubing, and one where the pump needs to be attached.
It does not include ball valves and check valves, neither does it include float switches and the like, except perhaps in the top-of-the-line units.
If the filter has a skimmer built-in, a hook-up for that should be provided as well. Again, make sure that the skimmer can be used with ozone if you are planning to do so, and that it is placed in such a way, that flowing the outcoming water over carbon is easy.
It should also not allow air-ozone from getting into the back compartment where your biological medium is, as ozone will destroy the bacteria in the biological filter.
To save on the total height, look for a filter that has a 90 degree angled fitting for the water inlet at the top.
There are many uses in the Hobby for float switches. Level control is an important feature of a modern aquarium, and you should certainly consider adding it to your tank, especially since inexpensive models have now become available.
Keep in mind that water levels can be controlled in various ways
Float switches that control the "low" do two main things for your system's stability and protection:
They prevent the pump from running dry when the water level in the sump gets reduced because of evaporation, or when you remove water yourself, for whatever purpose you may do so (for example when changing water).They even out (balance out) the amount of water going up to the tank, and the amount coming down to the filter as, if the level in the sump drops too much (you regulate the height at which the float switch triggers) because more is going up than coming down, the float goes down, and stops the pump for a short period, until the level in the sump goes back up.
Float switches that control the "high" serve the following purposes:
add from a reserve vat. When the level in the sump reaches the desired level (which you decide on) the float shuts the pump that is adding water down, remotely. Indeed, the pump is in the reserve vat, the float switch is in the sump, and senses the level as it goes up.shut down a solenoid valve that controls water coming a large skimmer to the sump, for instance. You are unlikely to use this feature in a basic system, however, because of the high cost of setting this up. A large and reliable solenoid (e.g. 1 inch in and outlet) costs close to $ 450.00.
When in the market for a float switch, shop around! You should consider the following types that are commonly available:
All have advantages and disadvantages:
The key when using float switches, is to make them trigger at the correct level. With mercury and infra-red switches this is real easy, with reed switches it is a little more complicated and time consuming.
The trigger point should always be at least 1.5 inches above the top of the intake hole of the pump. This to prevent air from being sucked into the pump because of a vortex that will form around the intake area, if the level in the sump is too low.
Air in the pump volute and impeller area, makes the pump run much hotter, and heats up the water too. Additionally the air may be broken up by the impeller, and extremely small bubbles may form. These are pushed into the tank, making it look real unsightly. Such small bubbles can also cause nitrogen gas bubble disease.
Small, reliable, float switches can often be obtained from Marine Supply companies and shops. They are usually operated in conjunction with bilge pumps on boats. Make sure that they have no metal parts that can come in contact with the water in your sump, except if the metal is 316 SS. Additionally, they must be made to run on 110 volts, not 12 or 24 volts.
[Albert J. Thiel requests that you make a $5.00 donation to the New Mexico School for the Visually Handicapped Children, 1900 North White Sands, Alamagordo, New Mexico 88310 (or other charitable group) if you download the entire book. This would be in lieu of the standard purchase price for this publication.]
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