Protein Skimmer For Tropical Freshwater

[FcF]

any advantage?

 

[Darkstar]

No not really. Only really useful in marine.

 

[FcF]

disadvantage?

 

[Ian H]

waste of money?

 

[MHunt]

In tropical tanks it actually benefits the tank to have more broken down organic compounds in the tank, it helps as part of the tank cycle to break down nasties and neutralise any stray chlorine and chloramine that may get their way into the tank. The by product of all this is nitrate, but at present there's no cheap way of removing that in a freshwater setup like there is in Marine with live rock. In fact there are even cases in marine fishkeeping where a skimmer is unnecessary. In fact I believe that because of the lack of salt in freshwater the skimmer wouldn't work.

 

[prankster705]

In tropical tanks it actually benefits the tank to have more broken down organic compounds in the tank, it helps as part of the tank cycle to break down nasties and neutralise any stray chlorine and chloramine that may get their way into the tank. The by product of all this is nitrate, but at present there's no cheap way of removing that in a freshwater setup like there is in Marine with live rock. In fact there are even cases in marine fishkeeping where a skimmer is unnecessary. In fact I believe that because of the lack of salt in freshwater the skimmer wouldn't work.

actually it's not the lack of salt that would make it useless, it's the density (I dunno if that's the right term either lol) (and yes I know the 2 are connected), but yeah, they're supposed to be useless in fw.

 

[Larissa]

Specific gravity rather than density I think. lol

 

[MHunt]

In tropical tanks it actually benefits the tank to have more broken down organic compounds in the tank, it helps as part of the tank cycle to break down nasties and neutralise any stray chlorine and chloramine that may get their way into the tank. The by product of all this is nitrate, but at present there's no cheap way of removing that in a freshwater setup like there is in Marine with live rock. In fact there are even cases in marine fishkeeping where a skimmer is unnecessary. In fact I believe that because of the lack of salt in freshwater the skimmer wouldn't work.

actually it's not the lack of salt that would make it useless, it's the density (I dunno if that's the right term either lol) (and yes I know the 2 are connected), but yeah, they're supposed to be useless in fw.

Well, salt, density, sg, they're all connected.

 

[Bignose]

Specific gravity and density are the same thing.

SG = density of a fluid / density of a standard fluid.

The standard fluid is almost always chosen to be pure water at 4 degree C which has a density of 1000 kg/m^3

So, you see the specific gravity is the just the density divided by a standard, it is still the same thing. And, yes, the specific gravity or density is primarily affected by the concentration of salt dissolved in the water. There are very weak temperature and pressure effects, and affects of the amount of nitrate and other dissolved organic chemicals, but they are negligible compared to the salt concentration.

To further complicate the issue, the real problem at hand is not that the density (or SG) of freshwater is wrong, it is that the surface tension isn't sufficient. A freshwater protein simmer would work if the pressure was increased a lot (a lot more than easily available in the home). Just like how the density and salt concentration are related, the surface tension and salt concentration is related. Dissolving salt in water increases its surface tension. So, as was stated above, a typical protein skimmer isn't going to work in freshwater tanks. So, it basically would be a waste of money/electricity. It won't harm anything, but I don't see much of a point.

 

[RipSlider]

I'll add even more to it than this


A fresh water skimmer CAN work... I have one working and am starting to think about shopping it around to see if one of the bi companies will buy it.

As has been said, if you use a marine skimmer in fresh water, you get very little in terms of results. The reason is complex, and is to do with surface chemistry and dipoles, but essentially it comes down to the fact that:

a) it is difficult to make small enough bubbles in a given time period and space to make it effective
B) there is a much smaller osmotic effect due to lack of salts in the water


However, this can be countered by using a different mechanism to create the bubbles, specifically a special bubble plate that a company in the US produces that produces incredibly small bubbles, smaller than a standard marine skimmers, and also using a coil with an alternating charge in it wrapped around the skimmer column to add a charge to the water, to replace the osmotic effects.

On my 1200l tank I was getting about as much skimmate as my friend was on a 1,000l marine tank and fish were in amazing condition.

There ARE however, issues:

column is 2 foot 4 inches tall so isn't for everybody

CO2 is ripped out due to the massive gas exchange, so plants do very badly indeed. Also, there is virtually no nitrate, and fertilizers go through a reduction process ( becuase I was using Ozone as well ), so you need to consign yourself to having no plants.

Still more fiddling to do in an attempt to make the column practical, but hopefully you'll be able to buy one soon.

Steve

 

[FcF]

thanks people

especially to the ones who care about my money

 

[MHunt]

Yeah it seems that the skimmers that do work take pretty much everything out of the tank that most freshwater systems need. I guess the only need for one on that scale may be in a large breeding setup to maintain top water quality for the fry without having to do regular water changes, but the cost would probably make it prohibitive.

 

[Larissa]

One might be useful in a large african cichlid setup where you have a lot of messy fish - not sure though.

 

[Colin_T]

For MHunt
Having rotting organic matter in the tank to give any free chlorine or chloramine molecules something to neutralise rather than the fish isn't the best idea. The resultant compounds are carcinogenic and can have an adverse effect on the inhabitants.

The idea of live rock does have merit though. The biological processes in fresh and saltwater tanks are principally the same. Ammonia is converted to nitrite and then nitrate. A denitrating filter passes water very slowly through an anaerobic filter. The filter develops bacteria that feeds on the nitrate and carbon and converts the nitrates into gas and other by products.
Live rock in a marine system has aerobic bacteria on the outer inch of rock but the inside of the rock is anaerobic and becomes home for the denitrating bacteria. A freshwater tank should be the same.
I think the biggest problem encountered with this idea would be the number of fishes in the average freshwater tank and the biological load they would place on the rock. Too many fish getting too much food and there isn't enough rock to house the denitrating bacteria. It might be something people could try. Reduce the number of fishes in the tank and add a few big rocks. See how your nitrates go.
Many marine systems also use sumps/ refugiums to house macro algae and these utilise the ammonia as soon as it is produced. Thus helping keep the nitrates low to begin with. Freshwater plants do the same thing.

 

[Bignose]

Having rotting organic matter in the tank to give any free chlorine or chloramine molecules something to neutralise rather than the fish isn't the best idea. The resultant compounds are carcinogenic and can have an adverse effect on the inhabitants.

Colin, this is the second time I've seen you claim this. Can you please cite some source that demonstrates the carcinogenic nature of the chlorine in the water?

Also, dechlorinator works pretty much instantly and the doses on the bottles takes care of many times the usual concentration of chlorine and chloramine in water from a processing plant, so even if the low levels of chlorine in the water causes cancer (which I am skeptical of), the declorinator neutralizes the chlorine pretty much immediately anyway.

I will make the same promise that I make every time I am skeptical of someone's post. Bring me the objective scientific proof, and I promise I will change my mind. But, just to give you some source of my skepticism here, I have earned a doctorate in chemical engineering and along the way I've working in a laboratory where we studied the components of water. I certainly don't claim to know everything about it, but I have to say that I've never heard of anything even similar to the chlorine in the water causing cancer. I also am not trying to claim an appeal to authority (because that is a logical fallacy and makes any argument weaker, not stronger), but I am trying to show that I've done work in a very related field, and never heard anything similar to this. So, again, please bring me some proof of these statements, I'd really like to look them over. I make the promise, again, publicly, that if the proof you bring is objective, preferably peer-reviewed though not necessarily, scientific in that there were controls and double-blind conditions, I promise I'll change my mind. Until then, I'm going to point out that I think that this is utter rubbish. If the chlorine in water caused any amount of measurable cancer, why would so many water plants continue to use it? There are other alternatives, like ozone.