Protein skimming for freshwater.

[Don Hiatt]

Has anyone here had any luck with protein skimmers in freshwater aquariums? I have heard from different sources on this subject and some people say they work and some say they do not. I read an article in Freshwater and Marine Aquarium back in 1992 about the use of protein skimmers in freshwater ponds. The units that the author made produced foam. If someone has experience with this, please let me know.

[Lisachromis]

No experience with this, but my understanding of this is that the water has to have a lot of protein in it for it to work in freshwater. Water changes clear this up so well, that why would you bother with it? I would imagine that the efficiency of this in freshwater would all depend on the tank and what's in it and what gets fed to it.....

[Don Hiatt]

Water changes do help allot. I do 30 to 50% changes on a weekly basis, but I would like to get as much waste out of the water as I can between changes. I have good filtration now, but my larger cichlids can be a little messy. My main concern is the large amounts of waste my fish produce. I think im going to try out one of the units that are integrated into a power filter.

[polleni]

Protein skimming relies on the air / water surface of the air bubbles. It works in exactly the same way your own alveoli work in your lungs which allow you to exchange CO2 for oxygen. Thus, in order to be effective you need maximum surface for the air / water interface. In marine tanks, many tiny bubbles are produced which means that the surface is maximal. In fresh water this is not so. You get large bubbles which mean a huge volume but far less surface. The bubble is a sphere which means that it has maximum volume with the least possible surface. If the same quantity of air is broken to more bubbles than you increase the surface tremendously. This is why skimming is effective in marine tanks and very difficult to work in freshwater tanks. With many extremely fine diffusers and many strong pumps you will have a good effect but, as Lisa already said, what is the reason to spend money on this project ? A water change will take away much more than a skimmer will.

The main reason most matine aquarists use the skimmer is that they can't perform large water changes because of the fragility of their systems AND it is very costy to do so.. salt doesn't come free as your tap water !

Finally, the skimmer can't tell what is useful and what is not. It will take out the organic matter but alongside it will deplete your tank of many micronutrients, most drugs etc.. Once I used a medication containing methylene blue in one of my marine tanks and I was nastily surpised to see my water clear in less than an hour and a shinning blue foam in my skimmer..

[dstuer]

back in the late 90s Aquarium Fish Mag had plans by Stephan Mayer on building a Protein Skimmer for backyard pond. I modified the plans for my 150 gal cichlid tank, and later built another for my 100 gal.
After a large feeding of peas, the waste efluent of my skimmer can reach anywhere from 150 to 300 NTUs (turbidity units=dark green) while the tank stays less than 1(clear). I must admit that sometimes I get foam sometimes not. The 150 runs wet and the waste drains to the foor drain, up to 10 gallons over night. Makes for a lazy mans water change, just fill the tank sump with fresh every morning, if I'm going to be gone for a couple days I open a valve and the skimmer doesn't drip. My 100 runs dryer and waste goes to a plastic bag, about 100mls overnight and I just dump the bag. A Mayla cone snail stuck in the venturi of the 1/2" PVC aperature can stop the skimming all together, or a grain of sand can slow the 1200gph pump to stop skimming too, but these are (to me) normal maintanence chores. Even when not skimming the venturis ad aeration.

[Dan Woodland]

Don,

What are your tank parameters?
1. Number and size of fish
2. Staple food fed
3. Tank size
4. Filtration

In the past I've know others with this issue and theirs turned out to be too high a bio load on the tank set up (size/filter/fish etc...). Their fish were so large and a bit crowded that they had too feed tons of food. Since the fish were so large they made a mess and lots of uneaten food reached the substrate where the giants never ventured so the food rotted and caused some issues.

Are more frequent water changes possible, maybe you could set up an automated system on that tank to provide fresh water every day or two. Water is not free but a simple water system might be cheaper than a protein skimmer.

Dan

P.S. I’m no water expert but I would also consider the points Polleni mentioned…..

[Bas Pels]

Apart from the issues Dan and Polleni mentioned, a skimmer does not take out all there is to be remouved.

As far as I'm aware, I know almost nothing of marine tanks, in seawater preteins are not as easily degraded into nitrate as in fresh water. in any case, nitrates, phosphates et cetera will not be remouved by a skimmer as proteins are.

Therefore, I would spend part of my investment money on a good filter, turning proteins into nitrates and so on, and use the rest as a fund for waterchances.

Bas

[dstuer]

Sorry for the late response
I try to do a 10-20% water change per day, and the tanks are crowded. One is a 150 gal draining into a 50 gal barrel and 40 gallon planted sump. The other is a 100 gal, a 65 gal tank in the line draining into a 30 gal planted sump finally into a 50 barrel. The 2 skimmers are home made so the cost less than $75 each. Venturi valves were the $30 each and the most expensive parts.

[img]]
The bags of skimmer waste are not quite that dark, but almost.
[img]

[dstuer]

For the sceptics who think you can't get foam in fresh water

waste collected from the skimmer.

[dstuer]

Freshwater foam

[Don Hiatt]

I just happened upon this while checking the others posts. I don't know why I didn't receive notifications that I had replies to my post. Maybe I clicked on something I shouldn’t have.

Well, better late then never. lol


"Therefore, I would spend part of my investment money on a good filter, turning proteins into nitrates and so on, and use the rest as a fund for waterchances. "

Bas Pels,
I would say that the tank has enough filtration for its size (two large filters), but the tank in question is a little over crowded for now. I have three Oscars close to 10", four Managuense's all over 10 to 12" , a large (12"+) Sailfin Pleco and one mutt (6”). A little too much for a 125, but I have to put off setting up another fish room for now.

I do perform regular water changes. I do large scale water changes once every one to two weeks and at least 25% every few days. My water is clear and always tests out OK. I just don't want to starve my fish to keep the water clean in between water changes. I wanted to use the skimmer to take care of the leftover food and the soluble waste in between water changes.

The fish are getting enough nutrition as it is (pellets, freeze dried foods) and I know it’s not good to feed predatory fish every day either, but I like to feed fresh beef heart and seafood. This can cloud the water. I will also make 50 / 50 mixtures of beef heart and garlic. This can get messy but my fish love it.

dstuer,
It looks like you have your filtration set up in a sump. Do you use a wet / dry system?

I contemplated building my own, but the set up I have (Fluval 405 and Aquaclear 110) works well enough to leave it alone for now. I was thinking about one of the commercially available hang on tank models of skimmer.


"Are more frequent water changes possible, maybe you could set up an automated system on that tank to provide fresh water every day or two. Water is not free but a simple water system might be cheaper than a protein skimmer. "

Dan,

I thought about an automatic water change system. It’s just not something I can do in the rented space that I call my home. This tank is also in my living room. Not an easy thing to do from there.

Since I lost my colony of Herichthys tamasopoensis that I had for over 8 years, I scraped most of the tanks I had and only kept the 125. Since I only have 9 fish now, I condensed them into one tank for the time being.

I just moved last week and I will start the process of building some new racks for my office. I plan on trying a skimmer in the rack system to see how it works.

The only reason I brought this up was the fact that I read about protein skimming for a pond and it worked for the person who wrote the article. I am always looking for new ways to make my tank set ups better and too me, this appears to be a good idea.
Dstuer’s set up proves this.

Bas, Dstuer, Dan, Polleni and Lisa,
Thanks for the taking the time to respond. I value your opinions.

[dstuer]

My sumps are planted instead of wet dry, just a filter pad where water flows from tank. Love plants but can't even keep anubis or java fern with my fish. This way I get the best of both world with this method, ability to have them, and their use at nitrate reducers. Here's the article the idea came from, he explains much better than I can the attributes for fresh water skimming.
http://www.petsforum.com/cis-fishnet/afm/G29044.htm to sump.

[apistomaster]

Foam fractionation is only fractional effective(couldn't resist) in freshwater systems as it is in marine systems.
The costs in energy and equipment weighed against the benefits will lose out to making adequate water changes.
That dirty foam can be produced is undeniable but the dry weight of the substances removed is very slight compared to that which is accomplished with water changes. If it really was efficient aquaculturists would regularly employ this technology. Those who do use it generally are doing so in conjuction with the use of pure oxygen and ozonization.
Mainly to buy more "dwell" or exposure time to the oxygen and or ozone. They are not really expecting it to contribut to the actual removal of wastes. For that they still will rely on water changes. There is no free ride just some are cheaper than others. Whether the water quality is an issue for a pond keeper, aquarist or sewer treatment plant, the best solution to pollution is dilution.

[duanest]

My fractionator hangs directly above the sump, I noticed a stain on the PVC around it, and thought (duh) maybe too much of this spatter is going back into the tank. Pulled a plastic bag around the effluent opening of the fractionator and cut a hole in the bottom to drain into a small bucket. This is about a months worth of spatter.