Skimmer selection

[bamboozler]

Hi Roger,

I am considering the 3115/2 or 3130/2 skimmer for my 75G reef tank. The skimmer would sit in the settling chamber of my 30G sump/refugium, in 10 1/2" of water. Water level is steady, as the return pump is in a baffled chamber and cannot draw down the level in the settling chamber. However, there is some turbulence in the settling chamber due to the falling water from the tank above. Also, when I vacation I like to raise the water level 1" to allow for a weeks worth of evaporation. Over the next 4-5 days the level returns to the minimum 10 1/2", after which only the return chamber level continues to drop. Would any of these factors present a problem?

The return pump is rated at 500GPH, so the flow is rather gentle. Tank has 10 mixed corals, 5" regal & 5" yellow tangs plus 5 assorted fish under 2", plus the usual invertebrates, fed sparingly. Current skimmer is AS Seaclone, which is only producing about 4-6 oz dark skimmate per week, frequently less, and I have algae in the tank despite having very good water parameters. Would you be willing to venture a guess as to how much skimmate the Tunze would produce weekly?

Lastly, which Tunze product would best serve my system, and how would it compare to the AquaC EV-120 which I am also considering?

Thanks,

Scott

 

[rvitko]

I have used all three of these skimmers and it is difficult to clearly state that one is superior to the other. I like Tunze and I always have, personnally I will never use anything else. What is lost on most people is that the Tunze skimmers are part of a method not unlike Berlin being a method of keeping an aquarium, the skimmer is only a part of this method. I will first outline the pros and cons of the 3130/2 and the EV-120 and then discuss the more specific questions you asked.

3130/2

Pros

Extremely Quiet
Energy Efficient pump included- 21w- almost no heat production
Skimming stops when cup is full- no chance of overflow
Plankton Safe
Easy to set up, little need for constant adjustment

Cons

Closed loop design of plankton safe is not good at particulate removal
Water level and quality-i.e. specific gravity, must be constant to ensure good performance

EV-120

Pros

Powerful Skimmer, good at particulate removal
Tolerant of variations in installation

Cons

Depends on pump, energy eficiency and heat production are an issue as all possibilities use between 60-100w
Optional Collection reservoir with shut off required to prevent overflow
Bigger, Slightly Noisier
Every few days some adjustment of air required


The EV-120 will remove more material, A 3130/2 is more powerful than a Berlin or Turboflotor in my experience, the 3115/2 is about on par with these models.

You will probably wonder how the plankton safe feature works.

We rely on osmotic gradients. The pump is installed in a closed loop, the pump recirculates the water in the skimmer, the returning water passes a contact screen which allows chemicals present in the water to diffuse into the water in the skimmer by osmosis, in this manner it is not possible for any living plankton to enter the pump circuit and be destroyed.

Your installation sounds good, regarding flow through the sump and the like. I don't think the overfilling for vacation will be appreciated by the skimmer however. I would really consider a top off system of some sort. Ideally the skimmer would be used in conjunction witha BioHydroreactor and a mechanical filter 3166. The mechanical filter we use is a deep bed of acrylic wadding, this acts almost as a diatom filter in how finely it can polish the water. A portion of the effluent is used to feed the Biohydro reactor. The cartridge debris acts as the carbon source for the denitrating action of the Biohydroreactor. Every two weeks the cartridge should be exchanged, they can be easily rinsed after they are unraveled by a high pressure nozzle on a sink or hose or by throwing them in the washing machine without detergent. I can say from experience in my 120 reef with 2 Chromis, a pair of Bangaii, A desjardini tang, a pair of rose skunks, a haitian tube blenny and several corals that used together as a system, I have 2mg/l of nitrate, feed daily including silversides every other day for my large 3yr in captivity Ritteri and have not done a water change in over a year. My sand bed is the standard 1.5-2" of Knop reef base. I am using cabinet kit 19gca in particular, I also use two 7410/2 and the Calcium dispenser 5074. The skimmer alone will not provide the same results with regards to nitrate but used in combination with a plenum and good water management including weekly or biweekly 5% water changes you could also have excellent results.

 

[rvitko]

Scott,

I forgot to ask what kind of algae is troubling you. A skimmer improvement could help, it will degass CO2 and help raise the redox, by removing organics you will also prevent loss of buffering capacity. It could however be a chemistry or flow problem. I have found that the skimmer is important but keeping detritus from settling on the rock and mainatining a proper KH and calcium is also critical to beating algae problems. For your size tank I definitely think you need more skimmer than what you have but if your immediate concern is algae check into some other possible concerns first.

 

[bamboozler]

Roger,

Thanks for the very thorough reply. The algae is greenish brown, generally on the glass, occurs daily. Ph = 8.3 (requires lots of buffer to keep it above 8.0 though), nitrate = 0, 10% water change is done weekly with aerated/buffered RO, Kalk is dosed nightly. Flow seems pretty strong, and I do have 2 900GPH powerheads in the rear corner opposite the return pipe. I swear the algae has been worse since switching from 6500K CF bulbs to 10000k in September, but the LFS thinks it coincidence.

I have always had what I think is too much algae, but then the only skimmer I have had on the system is the SeaClone.

Do you have a dealer in the Madison/Milwaukee/Green Bay WI areas?

Scott

 

[tatuvaaj]

Scott,

I use two 3130/2 skimmers in my 212 gal tank and I have been extremely happy with them. Together they remove about 4 cups of dark skimmate in 3 days.

As Roger said, the skimmate is a little different from most other skimmers since Tunze skimmers don't remove particulate and/or plankton stuff from the water. With many skimmers you get a skimmate that smells really really bad but 3130/2 skimmate has more like a chemical smell.

Highly recommended!

 

[rvitko]

The nearest dealers to you would be Preuss Pet, and The Reef Tank in Michigan. For mail order we have Premium Aquatics, Champion Lighting and Marine Depot. It sounds like you have a fairly normal growth of common green algae. This is probably impossible to prevent. A bigger skimmer is a good idea and will help with your pH problems. Provided KH is at 10-12 DKH and the flow is diffuse with sufficient surface movement pH should more or less be automatically 8.1-8.2 during daylight hours, 8.3 and 8.4 are kind of unnatural readings and I don't know where this figure comes from, I have not seen any data of reef structures at any time of day where the pH exceeded 8.24. If KH is too high or low that could be the problem if flow and skimming are not sufficient excess CO2 could be accumulating. Based on what you said about using buffer and Kalk I have some concern that you may have an extremely high KH and a very low Calcium Level- get a good test kit for these two parameters they are critical. If you find your KH is high this necessarily means your Calcium is low, they exist in an inverse relationship- one precipitates the other. Your ideal is 12 and 400-450ppm. Use Calcium Chloride and water changes to drop the KH if you find this is your problem- cut it out with the buffer, use only as testing indicates, thats KH not pH. This will help with your algae problems not to mention growth of corals. For the algae just get some snails, a good mix of Turbo, Trochus and Astrea should do a good job, you may also consider an algae magnet or just wiping it down with a sponge, I really don't know any way around this. Yes, light could have an influence. Algae do prefer bluer spectrums of light, I think however that the advantages of the 10000k lamp in PAR value and color rendering outweigh this disadvantage. You didn't mention a wattage of lamp or brand. 10000k is more a marketing term than a real quantitative value. A good German 10000k is between 9000 and 11000k. Some so called 10000k are even 6000k or 14000k- read some of Sanjay Joshis work. In addition to K we have different peaks in wavelength to so it is fairly involved.