saltysupply
In Memoriam
so are we saying that it is possible to overskim now?
What does "over skimming" actually mean?
- Thread starter MikeBrke
- Start date
murraycamp
Member
I think so. But I think you would have to work pretty hard at it.
I think I need to correct myself. I said defining "over-skimming, for a particular coral, is easy... it is the point that the coral starts to starve". I think this actually defines "over-cleaning". To define over-skimming, wouldn't it actually be "over-cleaning" as a result of skimming?
So, I should have said defining "over-cleaning, for a particular coral, is easy... it is the point that the coral starts to starve (then add) - if this can be attributed to skimming, then you have over-skimming".
However, the problem here is that it is difficult to prove causality. I think it would certainly be easy to over-clean, for non-photosynthetic corals, fairly easy for many soft corals, and very difficult for many SPS corals. To attribute this to skimming, you would need to prove that the skimmer was responsible for the nutrient uptake, resulting in the demise of a certain coral or group of corals (or some other filter feeder etc...).
As I started to get at before, It would be more beneficial to measure the rate of nutrient export, from the skimmer, using some surrogate marker(s). This way, we could get an idea of the skimmers efficiency.
If you use a measurable and controllable marker *^* then you can measure it in the tank, measure how much is added to the tank, and measure how much is collected in the skimmer over a given time. If your removing more of the nutrient than your adding, then you can at least get an idea whether or not your over-skimming.
There are of course other problems, if the foam head collapses, due to insufficient protein, then you are at least momentarily under-skimming. If this is due to the fact that you have skimmed so efficiently that you have removed all protein from the water, then maybe you are over-skimming, but if it is for some other reason, such as a chemical reaction from over-saturation of protein and the protein is staying in the tank, then you are under-skimming. So there is an added complexity, because we also need to define sufficient sampling frequency and duration. This brings me back to my other point... at the moment it is kind of a theoretical black-box concept. It can barely be defined, practically speaking, and therefore, practically speaking, it is hard to even agreed upon what it is... Therefore for our purposes it's little more than a buzz-word. Right now, I'd settle for a way to measure skimmer efficiency other than the color of the skimmate...
*^* note: magnesium would actually be excellent â€"œ something along the lines of zooplankton would be better, however you can't really control its reproduction and it's difficult to measure â€"œ nitrates or phosphates would also be good, but difficult to measure how much your adding
stony_corals
New member
Good point... however, what if they aren't exhibiting PE for other reasons such as reducing their surface area to reduce light to their zoox? Or if they are being pestered by predators? I'm skeptical of the interpretation of PE to mean anyone thing...
Look at the thread about people having ATI BM250s on 100g tanks, they couldn't get a foam head after two weeks, the reason, they have a really good skimmer that is way too big for their system. I wonder what their sps looked like? Were they pastel and looking N limited? Is this overskimming?
hahnmeister
In Memoriam
Well, in general, polyp extension on a daily basis does vary according to the 'food' the coral smells in the water. Dosing vodka does increase the PE, and some SPS, like montipora, dont feed on phytoplankton as much as bacteria-based plankton, so it makes sense. I hear what you are saying... predation, lighting, chemistry... always factors... but all things considered to be constant other than bacteria in the water, it seems to hold true.
edandsandy
Active member
I am confused!, I have a 120g reef with a 300gph refugium & 175gph wet/dry, I JUST got a 300gph skimmer with a mag 12. Will I be over skimming now?
Out of curiosity, and m2434 you might be one to answer this, is there a way of objectively measuring the dissolved organic compounds (DOC) in water?
Personally, i am data-driven when it comes to topics like this. For example, do we know, at the microscopic level, what is actually in skimmate? Can we observe phytoplankton with a microscope? Can we observe zooplankton? If so, what species, is it all of them or only certain ones that get taken up? I think this type of data would really move the over- under skimming debate toward providing some objective, measurable guidelines for hobbiests.
This is not to say that this thread is not useful! I like these discussions as they get people to think about some of the terms we toss around and the practices we advocate. Honestly, how much do we really KNOW about what we do? Much of it, to me anyhow, seems to be educated guesses and trial-and-error. Sure, some practices, such as skimming, we know to be beneficial overall, but do we really know why based on data?
Personally, i am data-driven when it comes to topics like this. For example, do we know, at the microscopic level, what is actually in skimmate? Can we observe phytoplankton with a microscope? Can we observe zooplankton? If so, what species, is it all of them or only certain ones that get taken up? I think this type of data would really move the over- under skimming debate toward providing some objective, measurable guidelines for hobbiests.
This is not to say that this thread is not useful! I like these discussions as they get people to think about some of the terms we toss around and the practices we advocate. Honestly, how much do we really KNOW about what we do? Much of it, to me anyhow, seems to be educated guesses and trial-and-error. Sure, some practices, such as skimming, we know to be beneficial overall, but do we really know why based on data?
Well put. The discussion shares opinion and anecdotal information. Research is sparse throughout the hobby. However, Eric Borneman is doing some skimmate analyses as noted earlier in this thread. The opinion and anecdotes of a broad pool of experienced hobbyist is valuable and often all we have.
This discussion if nothing else will give pause to those who might otherwise charge on to completely erradicate nitrogenous and phophorous waste materials to the detriment of the organisms they are trying to nuture.
<a href=showthread.php?s=&postid=11141083#post11141083 target=_blank>Originally posted</a> by astrivian
Actually i just looked at Eric Borneman's thread and that answers several of my questions
I think that without lots of funding, the way Eric is measuring skimmate is probably as good as we could hope for in the hobby. There are ways to measure DOC, zooplankton, phytoplankton, bacteria etc... Getting a really accurate evaluation is tougher. For DOCs you could measure, in the tank and in the skimmer (accurately if you have lots of resources), but there is always the possibility of leaching from rocks or substrate... I think you'd have to do some tightly controlled pilot studies, to estimate how much you would expect to leach, based on the concentration of OC in the substrate, or rocks, based on how much is already dissolved in the water column. With any kind of living organism there's always the problem of reproduction. If you had a bio lab you could tag a know quantity of phytoplankton , bacteria etc... with a radioisotope, or a florescent tag and then measure how much ends up in the skimmer. Luckily Eric's a cleaver guy and I think his study is helping to at least gain some perspective on whats happening.
I have been working through this issue. My 180 has a MRC MR3R recirculating skimmer. The feed pump is 500 gph and the recir pump is a blueline 70 hd, 1750 gph and 39' head pressure. The pump was upgraded yesterday, previously it had a BL 55hd. I get skimmate collecting on the walls of the skimmer, but nothing has gotten to the collection cup in a long time. I have a large refugium with a DSB. I have no clue to how many pounds of LR ( a bunch, in tank, sump, and fuge). The stock list is:
Large Volitan Lionfish
Huma Huma Trigger
Niger Trigger
Spotted Hawk
Spotted Grouper
Maroon Clown
Yellow Tang,
Powder Blue Tang
Porcupine puffer
Lunar Wrasse
Blue Damsel
I have found that it needs few water changes, the nitrates remain at 10 ppm. Tim/Andy at MRC have figured that the refugium must be efficient enough as to prevent enough DOCs to skim ( I have played with the skimmer a lot). It has produced a little skimmate in the last 24 hours (I shipped the 55 out one day before the 70 arrived. Any insight? I am sure that I am going to get fussed at for the stock list, but parameters are always in check and I have next to no aggression.
Large Volitan Lionfish
Huma Huma Trigger
Niger Trigger
Spotted Hawk
Spotted Grouper
Maroon Clown
Yellow Tang,
Powder Blue Tang
Porcupine puffer
Lunar Wrasse
Blue Damsel
I have found that it needs few water changes, the nitrates remain at 10 ppm. Tim/Andy at MRC have figured that the refugium must be efficient enough as to prevent enough DOCs to skim ( I have played with the skimmer a lot). It has produced a little skimmate in the last 24 hours (I shipped the 55 out one day before the 70 arrived. Any insight? I am sure that I am going to get fussed at for the stock list, but parameters are always in check and I have next to no aggression.
I was hoping someone more familiar with your praticular skimmer would answer... but I guess not. My .02 - If skimmates collecting on the walls but not the collection cup, the water level in the skimmer isn't high enough. Maybe a design flaw or maybe you can just raise the height. On my two tanks I have this problem and it is a fine line between the water level being too high and too low. Good luck!
madadi
ReefOG
on the MRC skimmers,
if its the beckett type, it should have a gate valve that makes it easy to adjust the hight of the water level in the skimmer. turn the valve very slowly, come back 30 min later and then make further adjustments. don't mess with it too much too often, let it adjust first. your 70 pump should be more then enough to produce enough pressure in the skimmer to raise the water to the appropriate level.
i noticed on my PM bullet3 on an iwaki70 which is very similar to your skimmer, once i get the right water hight in the skimmer i only try to mess with the air valves. don't open your air valves too much because then too much air will push upwards at the skimmer head and it will keep braking your bubbles trying to collect over the rim. just my observation but i could be wrong, each system is different.
and about overskimming
i dont get much skimmate anymore since i upgraded to a rather large skimmer for the tank i have. im not worried about over skimming because i do love to feed the tank everyday! with my old skimmer my nitrates used to be higher then i wanted to so i had to limit my feeding and my fish suffered because of that. now my fish are fatter, corals grow more, polyp extension is better, and my nitrates is no longer a problem, thanks to a huge skimmer.
if you dont feed your tank often, i do think overskimming can cause a problem because it takes out nutrients and phyto that naturally reproduce in the tank and compensate for your lack of feeding. if you feed heavily, like myself, a large skimmer is a big plus. even if it overskimms, your corals still get fed every time you feed the fish.
alright, i got to go feed the fish!
if its the beckett type, it should have a gate valve that makes it easy to adjust the hight of the water level in the skimmer. turn the valve very slowly, come back 30 min later and then make further adjustments. don't mess with it too much too often, let it adjust first. your 70 pump should be more then enough to produce enough pressure in the skimmer to raise the water to the appropriate level.
i noticed on my PM bullet3 on an iwaki70 which is very similar to your skimmer, once i get the right water hight in the skimmer i only try to mess with the air valves. don't open your air valves too much because then too much air will push upwards at the skimmer head and it will keep braking your bubbles trying to collect over the rim. just my observation but i could be wrong, each system is different.
and about overskimming
i dont get much skimmate anymore since i upgraded to a rather large skimmer for the tank i have. im not worried about over skimming because i do love to feed the tank everyday! with my old skimmer my nitrates used to be higher then i wanted to so i had to limit my feeding and my fish suffered because of that. now my fish are fatter, corals grow more, polyp extension is better, and my nitrates is no longer a problem, thanks to a huge skimmer.
if you dont feed your tank often, i do think overskimming can cause a problem because it takes out nutrients and phyto that naturally reproduce in the tank and compensate for your lack of feeding. if you feed heavily, like myself, a large skimmer is a big plus. even if it overskimms, your corals still get fed every time you feed the fish.
alright, i got to go feed the fish!
if you dont feed your tank often, i do think overskimming can cause a problem because it takes out nutrients and phyto that naturally reproduce in the tank and compensate for your lack of feeding. if you feed heavily, like myself, a large skimmer is a big plus. even if it overskimms, your corals still get fed every time you feed the fish
Well said, I couldn't agree more.
Well said, I couldn't agree more.
