Taking Skimmer Off-line For 2 Hrs Daily

[William Morris]

I watched this video where Dr. Tim talks about not running your skimmer 24hrs a day.
The discussion starts around the 29min mark in the video - and it's part of a larger discussion on ways to battle algae in our systems.

The premise being the skimmer is taking the bacteria out of the tank.
By shutting it off for a few hours a day you allow the bacteria to absorb the nutrients.
When you turn it back on the nutrients are exported via the skimmer.

So, for a week I have been doing this and it dropped by phosphate from 1.1 to .08.
I did not do anything else to the system in this week except dose Alk and Cal.

Interested if others have tried this approach and what their results were.

 

[PeterC99]

Very interesting.

My skimmer goes off about 4 hours a day when my pH reaches 8.4. I run a CO2 scrubber and recycle air through skimmer cup. My Apex turns the skimmer off when the pH reaches 8.4. In the evening when pH drops back to 8.36, Apex tells skimmer to go back on. Noticed my PO4 dropped from .1 to .04 during this time. Was wondering why but now have an answer.

Thanks!

 

[Randy Holmes-Farley Verified Community Expert]

I do not see a convincing reason to do this (and see clear reasons not to, such as lack of aeration), but it is easy to try.

VERY important is to be sure the water does not stagnate in the skimmer and risk producing hydrogen sulfide.

I also think that the phosphate drop (if real, I suspect test error as that is a mammoth drop) did not come from turning off the skimmer for 2 h.

-

 

[William Morris]

Thanks for your input Randy - always appreciate your viewpoints.
I am very meticulous with my testing - I use the ULR Hanna to check phosphates.
But, it could be an outlier.

I run the Tunze 9001 so I just take the cup off and the pump on for aeration.

Do you agree with the premise that allowing the bacteria to build with the skimmer off will help in the exporting of nutrients when the skimmer is turned back on?

 

[Randy Holmes-Farley Verified Community Expert]

Do you agree with the premise that allowing the bacteria to build with the skimmer off will help in the exporting of nutrients when the skimmer is turned back on?

No. IMO, that doesn't make much sense.

Most reef tanks are carbon limited, not bacteria limited. That is why organic carbon dosing helps drive bacterial growth and removal of nutrients.

Taking a tank and stopping skimming export for 2 h would have zero impact on all benthic bacteria, and only a small effect on suspended bacteria since in two hours the levels can't change all that much.

In essence, this idea should say that less skimming should give a lower nutrient tank. I don't believe it.

 

[William Morris]

Appreciate your input. Thanks

 

[Oldcoder]

I also shut both my skimmer and my UV off for two hours a days for a different reason. I was trying to raise nutrients and I also use Red Sea reef nutrition my assumption was this would help raise the nutrients and leave the organics from Reef Nutrition in the water column longer. This is just me thinking not and expert in anything.

 

[boxsterm911]

I saw the same talk, and implemented on my tank. I turned off the skimmer 2 hrs each night (on a timer). My tank is relatively new (about 7 months). I was having a little bit of algae issue. It has been two weeks, I did notice an improvement with less in algae on the rocks. Nothing else has changed.

Didn’t test my parameters yet. I would say it’s had been a positive for me. I don’t think 2hrs a day hurts. The flow is still on in the tank. Will test my parameters in the next few days.

 

[Randy Holmes-Farley Verified Community Expert]

I saw the same talk, and implemented on my tank. I turned off the skimmer 2 hrs each night (on a timer). My tank is relatively new (about 7 months). I was having a little bit of algae issue. It has been two weeks, I did notice an improvement with less in algae on the rocks. Nothing else has changed.

Didn’t test my parameters yet. I would say it’s had been a positive for me. I don’t think 2hrs a day hurts. The flow is still on in the tank. Will test my parameters in the next few days.

IMO, I would try to smell the water that first comes out of the skimmer. 2 h off enclosed in tubing might be enough for reef tank water to become anaerobic and potentially product hydrogen sulfide (smell like rotten eggs)..

 

[arking_mark]

IMO, I would try to smell the water that first comes out of the skimmer. 2 h off enclosed in tubing might be enough for reef tank water to become anaerobic and potentially product hydrogen sulfide (smell like rotten eggs)..

So my skimmer only runs to raise or lower my pH. It probably runs for 8 to 16) hrs a day (mostly at night). I have not experienced any hydrogen sulfide. Although, the skinmate smells just as bad.