DIY Guide to Aquatics

1.0 Introduction

For many individuals aquariums are much more than a hobby, they are a way of life. As such, through copious amounts of time and money, we strive for the optimum living conditions for our aquatic friends. However, money and time are two resources which seem to be dwindling in modern society. Chiefly among them, money is the hot commodity which limits the quality and growth of our way of life.

When given a choice, we invariably buy the best possible equipment within the constraint of our funds. Therefore, why not invest in the best possible aquatic environment while not committing vast amounts of capital? Thus the Do-It-Yourself guide to Aquatics.

This guide will give practical designs and implementations of wet/dry filter systems, protein skimmers, lighting hoods and stands. Through personal experience and information gathered from the net.gurus, all the elements for building and operating an advanced aquatic environment on a poor person’s budget will be given.

2.0 Wet/Dry Filters (W/D)

Although the importance of wet/dry filters in the advanced marine reef keeping arena has diminished considerably of the last few years, the benefits of using a wet/dry filter for basic marine environments and freshwater setups are still enormous.

2.1 How They Work

There are 3 main components of a W/D filter system: prefilter, bio-tower and sump. The prefilter siphons water from the tank into the bio-tower. The prefilter also filters (as the name implies) the water prior to coming in connect with the bio media. The bio-tower contains some diffusing mechanism (to be described later) and bio media, on which the bacteria colonize. The final component is the sump. The sump is nothing more than a small tank to hold water and other filter material (if you wish).

The basic operation is that water flows from the prefilter to the bio-tower. The bio-tower, using a drip plate or rotating spray arm, spreads the water over a large area of bio media, which after time, contain nitrifying bacteria. Dispersing the water acts to aerate the water and denitrify it through contact with the nitrifing bacteria. The water drips through the bio media and collects in the sump. Carbon and buffers may be placed in the sump to aid in chemical filtration and long term stability.

2.2 Prefilter

There are different configurations for prefilters, but the best external prefilter seems to be the dual overflow approach. The includes two overflow boxes, one inside the tank and the other outside. The inside box has a grate near the top which allows water to flow into the box and collect. The outside box has an outlet or bulkhead on the bottom to allow water to drain from the overflow to the bio-tower. Figure 2.2.0 illustrates the basic setup. A U-tube feeds water from the inside box to the outside box. Additionally, the bulkhead is usually covered by some filter media. This way the water is filtered prior to entering the bio media (hence the name prefilter).

Figure 220
Figure 2.2.0 – Overflow

The advantage of the dual overflow construction is the way water flows to and from the W/D. With the pump in the sump, water is forced into the tank from the sump, which in turn overflows into the inner overflow box. The U-tube feeds the water to the outside box and back to the sump. Should there be a power outage or a pump failure, the water will only drain from the tank until the level drops below the inner overflow inlet grate and then the siphon will be broken. Once the siphon is broken, no more water will flow to the sump. If the sump has enough volume to compensate for the extra water, then no water will be spilled. Moreover, the entire tank’s contents will not become part of the floor.

Construction of the overflow boxes require nothing more than a few pieces of acrylic and some acrylic bonding material. The general net.concensus is that actual acrylic welding materials are the best for this job, but any adhesive with says it bonds acrylic will work. The critical thing here is that the boxes do not leak. Waking to find a few inches of saltwater covering the floor and air-dried fishes is not a good thing. Appendix A contains exact plans for the construction of the overflow boxes.

It should be noted that the prefilter mechanism will be one of the few components that is visible. If you don’t feel confident that you can produce a visually pleasing piece of art for the prefilter, a commercial prefilter is an acceptable choice. Good prefilters can be had for about $50 mail order.

2.3 Sump and Bio-tower

Figure 2.3.0 shows the relation of the bio-tower to the sump space. The sump space and Bio-tower are contained in one functional unit. The bio media fills the bio-tower and water drips down over the bio media from above into the sump area.

There are various opinions about which method of dispersing the water is best, a drip plate or a rotating spray arm. A drip plate will clog with time, and a spray arm might stop rotating at times. A drip place can be cleaned and kept from clogging, so drip plates are used in these designs. They may very well be replaced with a rotating spray arm.

Sump/Bio-Tower Configuration
Figure 2.3.0 – Sump/Bio-Tower Configuration

2.3.1 Sump

Construction of the sump body can be as simple a buying a small tank, or as complex as building one from whatever material is handy. The preferred method is the former. Buying a small tank, or any container which holds water is by far the most simple and easiest route. However, if you have the desire, a sump can be constructed from acrylic plates in a relatively simple manner.

The size of the sump is system dependent, but it should be large enough to hold all the water that will drain back into it during a power outage. The greater the sump space, the less the chance it will overflow during a power outage or if the pump fails.

2.3.2 Bio-tower

The bio-tower holds some of the same interests as the sump. It can be bought or made, depending on the level of resources you are willing to put into the construction. The pre-made bio-towers of choice seem to be trash cans, or paint pales. Basically the only requirement for the tower is that is fits into the sump and has a flow through bottom.

As a general note, the bio-tower should sit a few inches above the water line, so the water can drip into the sump. Other filter material can be place under the bio-tower or in the direct flow path of the water as desired.

Next comes the bio-media. Once again there are two basic choices for media, DIY and commercial. Commercial bio-media costs about $10-$15 per gallon and looks like a spacecraft from a sci-fi movie. The DIY media can be just about anything you wish that has good surface area and won’t collect a lot of detritus. Popular bio media include shotgun wadding, cut straws, packing peanuts, and Easter basket grass. Shotgun wadding is the most similar to commercial media in terms of size and shape, but the bacteria are not picky and don’t care what esthetic value the media has.

Whatever bio media is settled upon, be sure that it will not leach toxins into the water. Most plastics are safe, but some concern has been raised against colored shotgun wadding in that may be manufactured using recycled plastics and therefore have the potential to leach nasty chemicals into the water.

2.4 Construction of a W/D filter

For the following design we are going to use a ten gallon fish tank as the sump and a 5 gallon trash can as the bio-tower (15 gallon tanks work better as they are longer, but 10 gallon tanks are usually more readily available and cheaper). Also, we are going to use a commercial prefilter for the best possible esthetic value ;).

For the bio-tower, cut the bottom out of the trash can, leaving a 1/4 to 1/2 inch lip around the edge. Fit some “egg crate” over the hole to hold up the bio media. Fill the tower with whatever bio media is available.

Construction of the drip plate is not so easy, but certainly no stretch for a novice home improvement type. The drip plate must fit inside the bio-tower and the top should be flush with the top of the bio tower. Depending on the configuration of the tower, either a round or square drip plate can be made. Assuming tower is square (which is easier to build to), cut a square piece of acrylic plate that fits into the tower, but doesn’t slide all the way down. If the piece slides, it will have to be supported with hooks, egg crate, or whatever is on hand (this is not critical). Take the plate and drill 1/16″ holes spaced about 3/4″ to 1″ apart. Leave about a 1/2″ border around the edge and about a 3″ space in the middle in where no holes are drilled. Next cut some acrylic plates about 1 1/2″ to 2″ in height and the length of the drip plate walls. Build a box using the walls as such:

Drip Plate Construction
Figure 2.4.0 – Drip Plate Construction

The box acts to collect water and allows it to evenly drip through all the holes in the drip plate. The area in the center is where the water will enter from the prefilter and splash down onto the drip plate. You don’t want the water to be forced through just the center, so there are no holes there to allow the water to collect and distribute. The drip plate should be constructed of at least 1/4″ acrylic so that it won’t sag in the middle and unevenly distribute the water. The thickness of the walls are not so important, but something too thin will cause problems when it comes time to glue it all together.

Next use another piece of acrylic plate to cover the drip plate (and the top of the bio-tower if desired). The plate should have a hole cut in the center where an elbow can be placed to connect the outlet hose from the prefilter, as shown in Figure 2.4.1. To plum the cover, use a PVC elbow and coupler which has a slip fitting on one end and a threaded fitting on the other (most commercial prefilters will come with an elbow and coupler). The coupler should screw into the elbow and fit tightly against the cover plate (use O-rings to ensure a good seal). Figure 2.4.2 shows the pluming.

Drip Plate Cover
Figure 2.4.1 – Drip Plate Cover
Drip Plate Pluming
Figure 2.4.2 – Drip Plate Pluming

The cover should have some sort of rests or blocks on it to keep it from sliding around. The blocks should fit just inside the drip plate box and make a snug fit to keep the cover from pulling out easily. Additionally,
the height of the drip plate box walls depend on the length of the coupler. You want at least an inch between the plate the coupler (you can cut the coupler if you want).

The final step is to put the cover on the drip plate and connect the hose from the prefilter to the drip plate cover. The size of the hose is not real critical, but it has to be larger than the return hose from the pump. 1 1/4″ piping can be readily had at any hardware/home improvement store. Fashion the hose to the bulkhead of the prefilter and to the elbow of the drip plate cover. Make sure that the hose fits well and will not leak (hose clamps might be needed for this). As note, if this filter is intended for saltwater applications, all of the parts must be non-metallic.

Once the system is set up, test the drip plate and adjust the size of the holes to allow about 1″ of water to collect. If the holes are too small the drip plate will overflow, if they are too large, it will run dry (running dry is better than constantly overflowing). Holes of about 5/16″e; to 7/16″e; will work nicely. Also, additional mechanical filter media can be placed over the drip plate for high quality filtration. 50 and 100 micron filter felt can be had from most mail order places.

2.5 The Cost

Total cost of the system will vary according to local prices, but a general guideline is as follows:

  • 10 gallon tank – 7.00
  • Acrylic Plates – 3.00
  • 5 Gallon Trash – Can 2.50
  • 10 ft. of 1 1/2 hose – 5.50
  • 5/8″ Return Hose (6 ft) – 4.00
  • 1 1/4″ elbow & coupler – 0.63 each
  • 1 1/4″ pipe (10 ft) – 1.20
  • Commercial Prefilter – 50.00
  • Shotgun Wadding – 15.00
  • Hose Clamps – ~1.00
  • Total – 89.46

The price of the whole system will be about $160 including a decent sized pump (something like an Eheim 1250). You could save some money by building the prefilter from scratch. All the components for a good prefilter should be no more than $20, so the whole system would be about $130. In the long run, you will save about $65 dollars over a commercial unit and (to coin a phrase) achieve some sense of pride.

3.0 Protein Skimmers

3.1 Protein Skimmers, How They Work

The idea behind a protein skimmer is to remove organic waste products before they have a chance to convert to nitrates. This is achieved by forcing small bubbles through a column of water. Best results are had when the water flow opposes the flow of the bubbles (i.e., bubbles flow upward as the water flows downward). This increases the contact time of the bubbles with the water and allows a greater probably that nasty organics will be pulled from the water.

All a skimmer consists of is a column of flowing water, some sort of bubble generation, and a collection cap to catch and hold the dissolved organic particles in the water. There are two type of skimmers, classified by their bubble generation method: air driven and venturi. Air driven models use an air pump and airstone to bubble air into the water. Venturi models use the Bernoulli effect to generate bubbles in the water. Air driven models are cheaper, but require more maintenance than their venture counterparts. Venturi models are more expensive to purchase and have a higher daily operating cost (they require powerful pumps for the best results), but are generally more efficient than air driven models (more bang for the buck as it were).

I have no direct experience in building venturi skimmers, so it will be left to the reader as exercise to investigate their construction. The following section will concentrate on counter current air driven protein skimmers. It should be noted, down draft skimmers are probably the best these days.

3.2 Counter Current, Air Driven

A Counter current air drive protein skimmer is nothing more than a long tube with water entering at the top and exiting at the bottom. Place an airstone in the middle of the tube and you have yourself a protein skimmer. There are things that can be done to improve on the design, but most of them are just convenience things that make our life easier and don’t necessarily improve the quality of the skimming process. Figure 3.1.0 shows the basic skimmer model. The skimmer has a reaction tube, collection cup and airstone. This particular model has been constructed with a removable collection cup to facilitate easy cleaning.

Counter Current Air Driven Protein Skimmer
Figure 3.2.0 – Counter Current Air Driven Protein Skimmer

The length of the reaction tube is some what arbitrary, but one too small or too long will not function properly. Sizes range from 20″ to about 48″. The reaction tube, collection cup and airstone cover are constructed from acrylic tube, and the rest is made of PVC and acrylic plating.

The disadvantage of using acrylic tubing is that it is considerably more expensive than PCV. Also, the largest extruded tube comes in 2 3/4 inch diameter, after that the prices goes way up. The whole design could be constructed from PVC, but then you couldn’t see into it and marvel over the amazing bubbles :-).

3.2.1 Construction

Construction should take about a half day (or faster if you’ve worked with acrylic before and feel confident with power tools). Appendix C contains very detailed dimensions for the design, so only an overview of the construction process will be given here. Start off by cutting the following parts:

  • 30″ x 2 3/4″ ID tube
  • 3″ x 2 3/4″ ID tube
  • 3″ x 1 1/4″ ID tube
  • 3″ x 1 1/2″ ID tube
  • 1 1/2″ x 1 1/2″ ID tube.
  • 3 – 4″ x 4″ plates of acrylic
  • 1 – 6″ x 6″ plate of acrylic
  • 2 – 1 1/2″ x 1/2″ PVC pipe

The acrylic tube should be 1/8″ thickness and the acrylic plates should be at least 1/8″ thickness. The 6″ x 6″ plate will be the base of the unit and the other plates will act as the separators.

You will need miscellaneous power/hand tools and some PVC/vinyl tubing. Specifically, you will need one PVC elbow, about six feet of 3/16″ vinyl tubing and about 6 feet of 7/8″ inner diameter vinyl tubing. The large vinyl tubing will fit over the PVC pipes and supply/return the water. The elbow will be connected to the outlet pipe (the one on the bottom) to feed the water upward. You could skip the elbow and use flexible tubing, but for $.34 it’s worth it. As another note, PVC and CPVC pipe, for a given inner diameter, have a different outer diameter. So if you use 1/2″ CPVC pipe, the same hose will not fit 1/2″ PVC piping.

Assuming that all the pieces have been cut, sand all of the edges so they are flat and smooth. It is critical that the edges are flat to make a good seal and so it won’t leak. After sanding the edges, start construction by drilling two holes in the 2 3/4″ tubing. The holes should be 7/8″ in diameter (1/2″ PVC will fit nicely into the 7/8″ holes). One hole should be about 1″ from one end, and the other should be about 2″ from the other end. Figure 3.2.0 shows this clearly. With the holes drilled, sand the holes to remove any large particles and insert one of the PVC pipes into the upper hole (the one 2″ away from one end). Glue the pipe in place with aquarium safe cement (GOOP brand name is good). Don’t use silicone sealant for this, the pipe has to be glued tightly to the tubing and sealant allows too much play in the joint. You can use sealant after the cement has dried to make the joint water tight if it makes you feel better.

While the cement is drying, take the last PVC pipe piece and glue it into the PVC elbow using PVC glue. Next, glue the elbow/pipe configuration to the lower PVC exit (the one 1″ from one end), as shown in Figure 3.2.0. Set the reaction tube aside and allow the PVC pipes to dry into place (you can hold them with tape so they would move while curing).

Next comes the collection cap and airstone holder. Start by drilling a 1 1/2″ hole into two of the 4″ x 4″ acrylic plates. The holes should be centered in the middle of the plates. One of the plates will serve as the bottom of the collection cap and the other will serve as the top of the reaction tube. Sand the holes to remove any large pieces of molten acrylic and any burrs.

Now take the 1 1/2″ x 1 1/2″ tube and the 3″ x 1 1/4″ tube and see if the smaller tube will fit inside the larger tube. Chances are that the smaller tube will have to be sanded down to fit into the large tube. If so, sand the smaller tube until it just fits inside the larger one. It should fit snugly, but not too tight as to make it difficult to pull out.

Top half of skimmer top
Top half of skimmer top
Bottom half of skimmer top
Bottom half of skimmer top
Adjust Bubbles
Adjust Bubbles

4.0 Hoods

Most beginning aquarists are content with using the everyday Perfecto hood or no hood at all. However, as interest grows and you want to keep live plants or invertebrates, the need for a high quality hood and lighting system is greatly accented.

Hood designs boil down to personal preference in many cases and most all designs are functional for their needs. The requirements for a hood are that it can house the lighting of choice, withstand the environment (e.g., water, salt), it can be cooled if required, and be moved/opened on a regular basis. Also. the construction must be sturdy because the hood will most likely be opened on a daily basis for tank maintenance. Because the design of a hood is so personal (different lighting systems, different requirements for space and size), a detailed design walk-through won’t be given here. Rather, various designs will be given and one detailed design will be presented. The detailed design is of a fluorescent hood with a flip top. The design can be altered to include metal halide lamps and fan cooling if desired.

Below is depicted various designs that I have seen and heard about from other aquarists. These are not the only designs and certainly should not be thought of as the only approach to a hood design.

Popular Hood Designs
Figure 4.0.0 – Popular Hood

Design A is the basic flip top model. It has a base unit and the lights are attached to the top which opens for maintenance. Model B is similar to A, except it is split in two vertically and half of the hood flips open. In this case, the front half may be opened and rested on the back half. This has great advantages over model A, which needs to be supported while it is open. Model C and D are variations on commercial hoods. Model C is simply a piece of glass with two strip lights resting on top. It is simple and cheap, but offers little aesthetic appeal and it makes it very difficult to do maintenance. Model D is an illustration of the basic plastic commercial hood. Model E is similar to A, except the front panel flips forward instead of the top. This has the distinct advantage that the lamps do not have to be moved for daily maintenance (Model D also has this advantage).

Appendix B gives detailed drawings for Model A, as well as mounting tips for the fluorescent lights. The design is for a 30 gallon tank which measures 36″ long and 12 1/2″ wide. The only parameters that need to varied in the design is the length and width of the shape. The height will accommodate most any lighting choices. Up to 4 fluorescent lamps will fit nicely into the design. More could be packed in, but it would be a tight fit.

5.0 Stands

Stands follow the same basic philosophy as hoods do: their designs are mostly personal preference. Regardless of the aesthetic appeal though, the stand must be capable of hold large amounts of weight, and therefore, must be very well build. Figure 5.0.0 shows some basic stand designs and a migration pattern. Model A is simple, basic and Spartan. Model B builds on A by adding a solid top and shelf. C adds doors and D is the complete enclosure. Various levels of ornateness can be had for the doors and moldings. Only your imagination limits you.

Stand Designs
Figure 5.0.0 – Stand Designs

The stand should be constructed of at least 2x4s. 2×4 side bars and 4×4 legs is good, but usually not needed for most applications. Also, screwing the wood together offers greater stability in the long run and allows the stand to be disassembled with little effort.

The most critical element in the stand construction is that it is sturdy and this cannot be stressed enough. However, the stand must be level as well. If the tank rests on an uneven surface, pressure points will build and a crack most likely will develop. Any solid top stand can be enhanced by placing cardboard or some moderately flexible material under the tank. This will allow the tank to `settle` into place once it is filled. If something is placed under the tank, it should be under the entire tank body not just one side or corner, thus reducing the stress on the tank.

Model A is regularly offered in pet shops for $50 or more when in actually it costs about $10 to build. One final note on the construction, the wood should be dried. If the wood is damp during construction, it will dry and warp leading to uneven surfaces.

6.0 Conclusion

The amount of money that can be saved by taking some initiative and a little time is tremendous. Moreover, there is a great deal of pride is saying that you created that hood, or you build the filter system from scratch. It’s a cheap ego boost that everyone could use now and then. Additionally, aside from getting a well-deserved pat on the back, you get something that you know you will like, because you built it to your standards. Don’t forget though, everything is learning process. You are bound to mess something up sooner or later, so don’t get discouraged. All things come to those who wait (so they tell me).

Comments & Questions

All comments and questions can be e-mailed to me.

I take full responsibility for content and blunders that may exist in the body of this text, but I do not take responsibility for the mistakes/blunders made on your part ;). Also, I apologize to the non-American readers, as all the measurements in the document are in inches. Remember, 1 inch = 2.54 cm.

“Documentation is like sex: when it is good, it is very, very good; and when it is bad, it is better than nothing.”

  • Dick Brandon

Appendix A – Sump and Overflow

Overflow Box
Overflow Box

Appendix B – Detailed Hood Drawing

Top View
Top View
Side View
Side View
Front View
Front View
Back View
Back View
Hood Lights
Hood Lights

Appendix C – Detailed Skimmer Drawing

Detailed Skimmer
Detailed Skimmer