Running skimmer <24x7 necessary (maybe bad)?

[patchesj]

I have been out of the hobby for 10+ years and recently restarted. "Back in the day", ULNS tanks were it and everyone built the largest most powerful skimmer they could. Food was rarely introduced and was targeted at fish, not things further down the chain. Now that I'm researching what works best for my tank, I'm realizing that a healthy balanced nutrient level can be maintained. I would like for my tank to have a wider variety of life in it. I have a refugium, but can't seem to keep macros or pods thriving. Everything seems to slowly die off. Combined with my 0 readings for nitrate, nitrite, and phosphates, I think I'm still keeping nutrients too low.

My tank is a 54g corner tank. 150w of LED lighting. 3x Koralia 2250gph powerheads. AquaC Remora Pro skimmer with Rio 1700 pump. ~5 gal HOB CPR refugium. I auto dose kalk for makeup water. PH/Mag/Ca/Alk all in great shape and very stable. Apex controller keeps everything going. Tank is fairly stuffed with LR/base rock, but built in a PVC skeleton and has plenty of space for flow.

My question is this: Are there benefits to turning off a skimmer for regular periods of time? I run no mechanical filtration on the tank, the skimmer is really the only form of active filtration. I figure I am getting 350+ GPH through the skimmer, turning the tank volume over every 8-10 minutes. There is plenty of flow in the tank without the skimmer running, and I provide 2 "calm" periods every 24 hours to help let the corals eat. What are the thoughts on shutting the skimmer down for 30-60 minutes a few times a day (maybe during the "calm" periods)?

 

[jimlin]

turning your skimmer pump on and off may wear out your pump prematurely. if you want macros to grow in your system, you probably need to feed more to get the nitrate and phosphate higher.

 

[patchesj]

I'm not only concerned about macro growth, but also about creating a wider variety of life in the tank including various forms of plankton. I'm concerned that the skimmer is removing nutrients and smaller creatures faster than they can reproduce.

 

[tanked37]

The skimmer is certainly doing that to some degree, but if you want more nutrients and pods, then I don't think turning off the skimmer is the best approach. One thing you might do is begin dosing phyto feast. That will boost both nutrients and pods. You will have to find the balance that works.

 

[dixiedog]

My question is this: Are there benefits to turning off a skimmer for regular periods of time?

In my opinion, no.

 

[ca1ore]

I think getting a sustainable population of plankton is nigh impossible in our small systems - at least not to the point of providing a material food supply for certain fish or corals. Inability to grow macros is generally a result of missing a key nutrient, but I'd be surprised if it were nitrate or phosphate (regardless of your zero test results). I would not be turning your skimmer off frankly. When I was getting poor macro growth, I actually started dosing very low amounts of an iron additive, and that helped quite a lot.

 

[hypnoj]

some reefers say that you can't grow macro in an ULNS. They say that it can't be an ULNS if macro is growing. I disagree. I believe most macro can live off the exact same nutrients as your corals. Therefor if your macro isn't growing, but the corals are, then perhaps it's a key nutrient missing. I don't see much of any benefit to turning off a skimmer.

 

[mwb32]

Sprung in his home tank has no skimmer and Lang has a test with the tank running the best when the skimmer is on 6 hours a day.

 

[ca1ore]

Sprung in his home tank has no skimmer and Lang has a test with the tank running the best when the skimmer is on 6 hours a day.

Trouble is these things are all anecdotal and do not carry the burden of scientific rigor - nor do they reflect adequate sample size. Somebody would need to setup, say, 100 identical tanks and then vary the degree of skimming to assess things like coral growth, macro growth, etc. Then we would have the basis on which to draw useful conclusions.

 

[patchesj]

I don't have room for 100 tanks.

I have been slowly increasing the amount of food I am adding to the tank (Coral Frenzy and Zooplan). It seems odd, but I'd say that the visible amount of misc organic "goop" is actually decreasing as I am adding nutrients. Potentially there has been an increase in pods and they are now also going after other lower algae. I have also recently modified my powerhead programming to allow for multiple calm periods during the day. SPS polyp extension during these times has been rather amazing (in particular the 2-4am period, not when I really want to feed....).

 

[mwb32]

Ca1, check out lens 4 tanks side by side study. So far the one with the best growth has a refugium and a skimmer that runs 6 hours a day let me get the YouTube site for you.

 

[mwb32]

Lengs one year review of the 4 systems. See attached video

http://www.youtube.com/watch?v=4iSW_GPP9ac

 

[patchesj]

Very interesting. My questions would be: 1. Does he have any commercial interest in the methods used in the ecosystem + type setup? 2. Are there any documents on the skimmer type, pumps, etc? 3. Any documentation on water quality test done during the year? 4. What 6 hours do they run the skimmer.

As mentioned in another comment, skimmer pump wear/failure might be a concern with daily startup of the pump. Any thoughts on this? Sure would be nice if someone made an electronic startup submersible pump that could handle the head pressure of a skimmer....

 

[patchesj]

I've figured out the answers to 1 & 2...

Ruling out Miracle Mud as a variable (used in multiple test tanks, with different results), on the face it would appear that less skim time is better. It would be nice to have actual measurements and/or photos of coral health/growth across the 12 month period.

 

[ca1ore]

Lengs one year review of the 4 systems. See attached video

http://www.youtube.com/watch?v=4iSW_GPP9ac

No question that is very interesting but, again, sample size is too small to be able to draw any statistically significant conclusions. All one can really say is to suggest that perhaps we over skim our reef tanks. With only a single tank represented for each 'condition' there are just too many other variables to consider. Absent, say at least 5 - 10 tanks for each 'condition' results remain anecdotal.

 

[leveldrummer]

turning off your skimmer is going to drastically kill the O2 levels in a tank wont it? and that inturn will likely cause fluctuations in the PH.

Skimmers only remove disolved organics. The micro fauna should be eating leftover food before it has a chance to break down. right?

 

[patchesj]

I would argue that in some cases the high volume of room air could bring the tank PH down... In modern tight homes, CO2 levels can easily be 2x outside air. I've tracked PH fluctuations in my tank when on vacation, I'm easily .15-.25 higher when no one has been home for 24 hours. And I have an ERV to help keep CO2 < 800ppm... I'm working on an air pump to pull outside air in and push it directly near the skimmer to help offset this. So I guess my point is that at least during the day, most tanks are probably CO2 absorbers/O2 generators. So running a skimmer during the day might be counter productive to PH control (unless you have PH > 8.5, and my tank was hitting that while on vacation).

I beleive that most zooplankton are primarily active during the night? So skimming at night would have a greater negative population impact than during the day. I am trying to find information regarding the vertical migration of phytoplankton.

So it seems the goal of minimizing PH disruptions by running skimmers only at night would work against to the goal of reducing mortality of plankton.

 

[Fishypapa]

Depending on the load and one's own dedication, you can remove a skimmer completely with more frequent water changes. (personally I don't have the time for it)
I'd definitely not turn the skimmer on and off though.

 

[_shorty_]

I would argue that in some cases the high volume of room air could bring the tank PH down... In modern tight homes, CO2 levels can easily be 2x outside air. I've tracked PH fluctuations in my tank when on vacation, I'm easily .15-.25 higher when no one has been home for 24 hours. And I have an ERV to help keep CO2 < 800ppm... I'm working on an air pump to pull outside air in and push it directly near the skimmer to help offset this. So I guess my point is that at least during the day, most tanks are probably CO2 absorbers/O2 generators. So running a skimmer during the day might be counter productive to PH control (unless you have PH > 8.5, and my tank was hitting that while on vacation).

I beleive that most zooplankton are primarily active during the night? So skimming at night would have a greater negative population impact than during the day. I am trying to find information regarding the vertical migration of phytoplankton.

So it seems the goal of minimizing PH disruptions by running skimmers only at night would work against to the goal of reducing mortality of plankton.

I would have made the opposite assumption about when to run. I'd expect running during lights on would be best. In my understanding, the addition of th CO2 is what can drop pH in your system. In addition, reduction of photosynthesis at night is what causes the drop in pH at night - as CO2 levels rise (are not consumed at the same rate). So you drop pH a bit with skimmer ON during the day (also adding needed CO2 for whatever photosynthesis is needed in the DT), then turning off during night hours. This should help reduce (to some degree) the pH swing at night. In addition, if there is something to your nocturnal zooplankton activity (It does seem that pods and more things are active during night hours - so it makes sense) it only compliments this strategy.

I personally am not against skimmers in any way but don't YET run a skimmer. I've been considering getting one to compliment my algae scrubber, and running it on a timer as you are considering. I am far from being as knowledgable as most on this site, but I will say that since the occasional addition of phytoplankton to help the population of zooplankton in my system, I believe (..unfounded assumption inserted here..) I have a healthy zooplankton population. In my 114 display, I put in a rail thin mandarine, who has grown fat and happy in a short time and the system also supports multiple wrasses.

I know I have lots of room for improvement in my system, though. It's a work in progress - and I expect that a skimmer will be an addition to my system sooner than later (just looking for a good deal on a used one). But this thread is interesting to me because it falls in line with some of my own thoughts.

Also the addition of the video is great. That was very interesting - even though I understand what some are saying about scientific evidence and wanting more information. however, IMO, it seems there is relatively little information in this hobby that is scientifically proven. Mostly anecdotal - and that's what we have to work with. It's part of what makes it an intersting hobby.