What are you referring to when you say downdraft protein skimmer?

I consider a downdraft protein skimmer one that is fed at the top, water flows downward and the output (for figurative reasons) is at the bottom.
Ok my understanding is 3 kinds of skimmers

1. A counter current uses small pump and airstones 
2. A Venturi that uses larger pump and a Venturi valve restrictor and small air intake 
3. A downdraft or ETS environmental tower scrubber. 

This has a TALL like 5 ft x 2" "tower" filled with bioballs, the water gets pumped into the top of this column under relatively high pressure through a fairly small 5/16 or 3/8 piece of plumbing fitting kind of like a tapered fire hose nozzle. At the top of this 2in x 5ft tower there is a hole about 3/8in that allows air to be "down drafted" into this bioball column The turbulated, air induced, foamed water then crashes into a small rectangular box about 8x8x12 inches the foam then drifts over to a LARGE like 8in acrylic reaction foam collection, accumulation riser, much like a regular protein skimmer. Bubbles burst foam rises, and overflows into a collection area like a regular skimmer.

 This works very well as there is virtually no restriction to a very high flow rate. Mine processes 1200gph for the skimmer and another main pump 1200 gph for the main

Simplified Reefkeeping

What is a protein Skimmer, and how does it work?

The heart of the modern reef external filter system is the protein skimmer. Make sure it is large enough to do the job. You cannot have too much skimming! Buy or make the largest one you can afford. Keep in mind: the larger your skimmer, the larger the skimmer pump will have to be. It should, however, be no larger than the main pump of the system.

I always cut the factory rating in half when planning for my skimmer. A protein skimmer is a clear plastic cylinder, usually 4-6” in diameter and 24-38” tall. Water is directed into the column by a water pump. Inside the column fine air bubbles are introduced and mixed with the water. This is usually done with wooden air blocks placed at the bottom inside the column, and fed with a strong air pump. This type of skimmer is called “counter-current” or “air-driven,” meaning that the water is pumped in at the top of the cylinder, and is directed downward at approximately a 45° angle. This makes the water swirl in the plastic column, while the fine air bubbles from the wooden air blocks rise to the top.

The bubbles drag water with them, rise to the top, and burst. Because there are dissolved proteins and wastes in the water, these too cling to the extremely small air bubbles, which rise and burst in the upper neck of the plastic column. A foam builds up in the upper neck of the plastic column, and overflows into a collection cup to be removed. This is also known as “foam fractioning,” and has been used in water treatment facilities. See Chapter 12 on the design of a protein skimmer.

A Venturi type of skimmer uses a Venturi air valve that is in line with the water being pumped into the skimmer. A Venturi eliminates the need for air pumps and blocks. It runs with a higher flow rate than counter-current systems, and therefore will need a stronger pump: one that is designed to operate under pressure, a “pressure pump.” This type of pump is designed to force water through the Venturi valve (see pump description). The Venturi is considered to be more efficient and overall less expensive to operate than air-driven counter-current skimmers.

The tower type:(Downdraft) There has been a revolutionary new design of skimmer on the market, which is neither Venturi nor counter-current. This new design is called E.T.S., for “Environmental Tower Scrubber.” Water is pumped through a tall, narrow “tower” (approximately 2” wide), filled with plastic media balls. The water is under considerable pressure, and it gets forced down the small neck through the plastic media, with air pulled in from the top of the skimmer creating fine air bubbles. Proteins and waste products cling to the fine air bubbles accumulating in a collection neck, rise, and overflow. This new dimension of skimming is extremely efficient and well worth considering, as the skimmer for your reef.

All skimmers operate on water being pumped in at the top and draining out by gravity at the bottom. The bottom of the skimmer should be above the top of the sump, thereby using gravity to full advantage. Most should have control valves in line before and after the skimmer to insure proper water control and fine tuning of the skimmer.

Also, you will hear talk of “efficient” skimming. This means that the skimmer is adjusted so that the accumulating foam has a relatively stiff consistency. If the bubbles are too close to the top of the neck, they will burst there (at the top), and you will not get the desired thick foam that accumulates until it reaches the top and overflows into the collection cup.

When the tank is first set up, a considerable amount of foam (waste) will be removed. Initially this is from die-off on the rock. The first couple of months are the most crucial from a monitoring standpoint. As time goes on and things balance out, the skimmer will be more predictable. This is good: when the skimmer is properly adjusted to produce a thick foam regularly, this indicates that the waste is being removed and the skimmer is operating correctly. The protein skimmer is the most important external filtering device of the enclosed reef, and will need sufficient monitoring for it to function properly, especially when it is first set up.

SKIMMER PUMPS

Here are some ideas on pumps.

1. Main pump, flow type:

You want to have a turnover of water at least six times the volume of the tank per hour with the main pump. For example, in a 55-gallon tank the turnover should be 55 x 6 = 330 GPH. This would require a main pump in the range of 330 GPH. Also, remember to take the vertical pumping action (head) into account when selecting the main pump. As a general rule, I would also add 20% to the figure as compensation for the head pressure. In this case, 20% of 330 = 66. Adding that to the original 330, we get 396, or about 400 GPH. By adding this 20%, I am assured of the pump’s capability. The main pump should be a flow pump, meaning it is designed to flow the water instead of having to force the water through something like a pressure pump. Also, I am not fond of submersible pumps, unless they are absolutely necessary in a particular situation. So, for a 55-gallon tank, we would use a 400 GPH main pump.

2. Skimmer pump:

For a Venturi skimmer, you will want a pressure pump. This is needed to force the water through the Venturi valve. For a counter-current skimmer, you will want a flow pump, because pressure is not necessary in this design. You will have to be very careful when selecting a pump for a factory-built skimmer. Closely follow the manufacturer’s recommendation of pump size! Skimmers are designed in such a way that the drain fitting is a certain size, and will only drain the water out so fast. I have found that valves are always needed on both sides of the skimmer. This gives you the advantage of being able to fine tune the skimmer, which is definitely necessary. If you make your own skimmer, the drain fitting can be larger than would be found on a factory-built skimmer. By having a large drain fitting controlled by a valve, you can increase the amount of water for the skimmer to process. Of course, this doesn’t mean you can have a small skimmer with a large drain hole and expect to remove waste properly. However, having a sizable drain fitting will give you more control over the rates of drainage and water flow.

Keeping records or maintenance and tasks on the reef aquarium,

It is a good idea to keep a notebook in which you record what you did and when you did it. Do not rely on your memory! Once some time has passed, your memory can fail as to when the reef was set up, when the rock was added, how long the tank took to cycle, when the inverts were added, how many of them there were, when the fish were added, how many of them went in, what kinds they were, what the results of your water tests have been, and so on.

Unless you are an analytical type, keeping a notebook and writing down all the things you initially do to the reef will seem like a waste of time. However, as time goes on (as it has a way of doing), you will begin to see the importance and benefits of keeping the notebook. If you do this from the start, there will be a minimum of guesswork regarding water changes, water quality, how long the reef has been set up, and the monetary value of the reef.

Here is a list of maintenance procedures,

Daily:

1. Check general appearance of reef.
2. Adjust protein skimmer.
3. Adjust water level (compensating for evaporation).
4. Feed livestock.

As needed:

1. Remove unwanted algae (on glass and overflow pipes).
2. Clean protein skimmer; change airstones; adjust Venturi valve.

Weekly:

1. Change prefilter pads.

Biweekly (alternately):

1. Change water.
2. Add trace elements.

Monthly:

1. Test water.
2. Clean the tank cover.
3. Wipe the light bulbs.

Every 3 months:

1. Clean the cooling fan(s).
2. Inspect and clean the water pumps.

Every 6 months:

1. Take down and completely clean the sump.
2. Take down and service the pump.
3. Replace light bulbs.

Once a year:

1. Completely take down, clean, and rebuild the reef.
2. 
   

Simplified Reefkeeping

Cloudy water problem in my reef tank

History:  62 gal. plexi that has been up and running for a year and a half.  Conditions have been real good until about a month or so ago.  Brownish/clouded water has been plaguing it.  I have a Fluval 303 canister filter and a CPR Backpack protein skimmer.  2 powerheads and a good heater.  I do 30% water changes every month along with changing the carbon in the Fluval. The tank used to stay crystal clear but not any more!  So far I have done extra water changes, bought two new bulbs (daylight and actinic) because the daylight was a year and a half old and the actinic 9 mos. old.  There has not been much in the way of algae on the surfaces (no more than usual towards the end of
  the cycle) but there has been a lot of tiny bubbles in the water and many have been accumulating on the Plexiglas.  I do NOT have an air stone and the protein skimmer does not seem to be putting many bubbles into the water. When I took a water sample out to show the local fish store, it was brownish/cloudy at first but then cleared up with just “dark brown cob web looking things floating around”.  All my water tests (ph, kWh, nitrate, nitrite, ammonia) have been great forever.  I tried covering the tank with blankets for a three day period to keep all light out in the hopes of killing a strange algae strain, but it didn’t do much.  My last water change was 50% about a week ago.  I’m almost ready to take my fish into a store and drain my tank and start all over.  Please help.  Any suggestions or question that I may answer would be greatly appreciated.–

  Humm.. this is a stumper
  Do you use reverse osmosis or deionized water? If so when was the last time you replaced the resin? The resin has a certain life span depending on the impurities of your
  water.  I would look into that.  Your maintenance sounds very good so I leads me to the source water.  Another thing is that canister filters are not generally used on modern reef tanks. I would seriously consider getting rid of it or if you must use it for a pump then remove the internal media. The internal media becomes a nitrate factory.. something you *Don’t* want or need.  do you have a sump? or area where you could put a fairly large amount of carbon where the water doesn’t have to flow *through* but around. Using sizable amounts of carbon this way will generally strip most any questionable material from the tank. I would go to a paint store and ask for nylon pain strainer bags about .50 ea. and use them to hold the carbon. In a 60 gallon tank I would use approx 3 to 4 oz of carbon at a time (in the bag) for about 3 to 4 days then replace and continue for 2 or 3 applications. If you see an improvement continue, if for some strange reason your corals react badly… discontinue use. They shouldn’t but one never knows.  Also, the small bubbles may be being created by not having enough skimming. It could be small particulate matter coming from the fluval.  I know a
  backpack is rated for a 60 but that’s probably pushing it. You may want to thorough clean the skimmer and possibly consider upgrading to a larger
  model.

What do I need for a Successful Reef Tank?

ITEM w/APPROX. COST

All the items here are needed for a successful reef tank

Note: these are approx retail prices,your cost may vary.

1. Deionizer or reverse osmosis water purifier $ 270
2. Resin for above, to replace every 6 months: 1 gal. $ 60
3. Bulbs: 48″ actinic blue & actinic white, 4 @ $25 $100
4. 30″ protein skimmer (Venturi)* $300
5. Pressure pump for skimmer, 500 to 600 GPH $90
6. Carbon pre filters for tap water: 1 @ $60, 1 @ $25 $85
7. Cartridges for above: 2 @ $12, 1 @ $5 $29
8. Sump box (for prefilter)* $150
9. Material, 6 packages floss prefilter $50
10. Main pump 500 to 600 GPH $90
11. Tank: 55 gallons* $70
12. Tank stand* $75
13. Light canopy to house four 48″ bulbs (with VHO ballast)* $300
14. Salt mix: 1 for setup for 55 gallon tank $18
15. Salt mix for water changes $18
16. Phosphate test kit $20
17. Test kit for ammonia, pH, nitrite, nitrate $45
18. Test kit for K.H. $12, calcium $12 $24
19. Specific gravity meter $12
20. Misc. (books, power strips, Kalkwasser, trace elements, etc.) $100

TOTAL: $1,906

* These items can easily be made by the hobbyists to save money, my book shows you how! Plus! other items not on the list. . .

What else do I need?

There are a couple of items I left out, such as a wave maker or surge buckets, timers for the lights, electronic pH testers, a generator in the event of a power outage, etc. I omitted these from the startup figure because they are not absolutely essential at the very beginning. They are important, beneficial components, but they can be added to the system later on if you prefer.

Simplified Reefkeeping

Planning the Reef Aquarium

The most important thing to do is to plan. The reason this is so important, in my opinion, is that so many people would like to get into this hobby, but they don’t plan. They walk into a pet store, see some nice live rock and coral and invertebrate, and they want to start a tank with that. After their purchase, they find their light is not strong enough, their water isn’t pure enough, they don’t have test kits or the right size protein skimmer. Their tank has not been properly conditioned, so the livestock they bought dies. At this point, they are shocked at what it will cost to get the proper items, and many just give up. Some others try to go on with half of the items they really need, still with bad results. Do not take this approach!

Summary: Understand what is involved

• Can you afford a reef tank?
• Write a plan
• List actual costs of items in your area
• Get an idea of a tank size

1. What size tank?

Its location, preferably near a sink (for water supply and drain). Will the floor carry the weight of the tank? Preferably away from direct sunlight. How much floor space will all the equipment take? Is there enough power supply to run all the equipment? Will there be enough room to service behind the tank? (See Chapter 12, on large tank location.)

2. Your budget.

Can you afford it? List and plan (very important). You may not be able to have everything up and running right away. But if you are patient and plan ahead, buying what you need as you can afford it, you will end up with the largest, most pleasing setup you can have. Put a lot of effort into the functioning of the system first, before adding live creatures to it. Plan for the ease of water changes and waste water drainage, the location of your tap water purification system, a large protein skimmer, and high-power lights with the proper bulbs. Once you have these in place (proceeding to each item as you can afford it), you won’t have to worry about jeopardizing the livestock you will buy. This is definitely the best approach. The next pages will give a recommended sequence for purchases.

In this hobby only bad things happen fast, due to lack of time spent on planning

3. Your time.

Remember: only bad things happen fast in this hobby, usually due to lack of time spent. Patience is invaluable. Keeping a reef will take a considerable amount of time, especially if you fabricate the components yourself. However, the rewards are exceptional! You will get tremendous satisfaction from knowing that you built components that are practical to maintain, and far exceed factory-built standards. But all this takes time,a lot of time. Are you willing to do water changes every two to three weeks? Are you ready to change your prefilter every week? Make limewater as needed for evaporation? Remove algae as needed? These are all responsibilities you have to take into consideration. (See Chapter 9, "Maintenance.")

What type of Filtration is reqiured for a Reef Aquarium?

The standard method of “purifying” the water for most reef aquariums has been to use a filter that is separate from the tank. This device, with which I’m sure you are familiar, is a container holding material that (1) traps particles from the water, and (2) has a sufficient surface area for nitrifying bacteria to colonize. This has usually been an enclosed type or “canister” filter.

A more advanced design was the “trickle filter.” This is an open style, relatively large, Plexiglas box containing a drip plate, prefilter, and spherical-type plastic medium. The drip plate would evenly disperse the water onto the prefilter material to trap particles. This in turn would trickle through the plastic medium, where the nitrifying bacteria would colonize and purify by nitrification. With all this “trickling” taking place, oxygen will get pulled into the water, ensuring that the aerobic bacteria remain aerobic.

The trickle filter is an excellent filtering system for fish-only tanks, where you need a large external area for the bacteria to colonize. Also, the open design of the trickle filter allows easy access to the prefilter material. These filters have been used on reef tanks, but most reef hobbyists realize that the bacteria will colonize any porous substrate (the live rock), and that oxygen is provided by protein skimming. The primary concern of reef keepers using trickle filters is that particles and debris get trapped and accumulate in the plastic medium. This accumulated, nutrient-rich debris then provides a food source for micro-algae.

Plastic media can trap waste, causing high nutrient levels—a food source for micro-algae A trickle filter on a reef system would inhibit bacteria from colonizing on the live rock, by maintaining a high flow rate of water through the media and providing oxygen to that immediate area. This would encourage the bacteria to colonize on the plastic media instead of on the rock.

If the plastic media were ever cleaned, the bacteria would die, sending the reef into an ammonia/nitrite cycle. This may cause death of the more fragile species of the reef, and at worst could cause a domino effect that would involve all but the most hardy specimens.

Faced with these two outcomes of employing plastic media, and realizing that live rock is an optimum substrate for aerobic and anaerobic bacteria, many advanced reef hobbyists simply did away with the plastic media. Those who had trickle filters with plastic media in operation would remove small amounts at a time (approximately 10% at every prefilter change once a week), ensuring that an ammonia/nitrite cycle would not occur, and thereby naturally relocating the bacteria to the live rock.

When I started in the hobby, it was recommended to have a trickle filter as described above. As time went on, even though I had live rock and sand and purified tap water, algae eventually became a problem. When I described this phenomenon to a friend, he shared his knowledge of plastic media and recommended the gradual removal of the plastic media. Slowly, the algae problem diminished in my tank. I will admit I was skeptical at first, but he was correct. This has become standard practice with almost all advanced reef keepers.

USING A TRICKLE FILTER AS A SUMP BOX

In perspective, the recommended filtration is still basically a trickle filter, without the media. We can use the box for a sump (to hold and control the water), and the drip plate and prefilter to provide their benefits. The concept is to change the prefilter once a week, to keep it from going “biological” (which could possibly lead to a small cycle), and to confine and remove the nutrient particles.

If you are currently using a trickle filter, you may be able to use it as a sump. It would have to be large enough to accommodate all the water needed for this type of method. Also, plumbing inlets and outlets may have to be added for feeds and drains to and from the protein skimmers, and possibly a main drain for the system. See Diagram 6 for the concept of a sump box with a prefilter and the location of the skimmers in relation to the sump box, as well as the relation of the sump box to the tank.

The following is an overview of the components for a modern reef filter.

1. Live rock, 1.5 to no more than 1.75 pounds per gallon.
2. Large protein skimmer capable of turning over water in the tank 6 times per hour.
3. Easily removable drip plate and prefilter material to clean or change once a week.
4. Large main pump capable of turning over water in the tank 6 times an hour.
5. Large sump box providing considerable turbulence, and capable of holding all the overflow of water from the tank, including the “working water.”
6. Denitrification areas .
7. Proper lighting.
8. Photosynthetic livestock.