internal vs external (recirc) skimmers, your opinions

I am looking for any information on recirculating skimmers. How does a recirculating skimmer work comparing with the in sump skimmers and what extra components may it need? I'm under the impression that they perform better their in sump counterparts?

 

really the difference is that you need a extra pump or generate flow to push the water through the skimmer. technically a recirc skimmer should cleaner the water better because it filters the same water for longer cleaning it more thoroughly. as far as if it actually works better it varies greatly between brands(but so do all skimmers). IMO a good brand is better then recirc vs regular.

btw im assuming your question is about recirc vs non recirc, and not internal vs external sump skimmers.

 

Whether the skimmer cleans the water more thoroughly depends on the size of the skimmer and how fast the water is being pushed through it. I would rather have a good in sump skimmer if space permits

 

My skimmer hangs off the side and does the job very well. I have no experience with inside sump ones but telling u my hang on one works great.

 

Here are some Pros of each:
Internal:
- Usually costs less
- Overflows are less of an issue

External:
- Recirculates the water for extended time within the skimmer (process more water)
- Less heat transfer
- increases sumps space and water volume
- Can be gravity fed or fed by a pump
- Can control the flow through the skimmer

 

Thanks JR, it was very informative. I really the idea of external skimmers since i can utilize the extra space in the sump for a bigger refugium.
I would also like to gravity feed the skimmer to eliminate the need for a feed pump, but how do one control the flow rate going into the skimmer?

 

FWIW, keep in mind that a mishap with a HOB skimmer can be disastrous, while the same mishap in an in-sump model would cause no issue.

Controlling the flow rate into the skimmer with a gravity feed can be influenced either by a ball valve coming out of the DT, or by varying the diameter of the overflow from the DT. One is adjustable, one isn't.

Good luck.

 

Thank you for your input reefsparky, yes i'm quite aware of the Murphy's laws and I do plan on installing a flood alarm to avoid catastrophes, also my sump is going to be in my basement so at least the damage will be contained should future flooding occur =)

 

I have both in my different systems. In my reef tank I have a hydor performer 500D and in my FOWLR I have a ASM. The hydor is the recirculating skimmer.

IMHO there are features on both that I like. I like the ASM because you can control the skimmer better. I can choose a wetter or dryer skim. I also like the fact that being in the sump if the cup overflows it will not flood my floor

I can not really control how wet/dry the skimmate is in my hydor. It produces a very "dry" nasty skimmate...which is very smelly. The actual skimmer and neck is bigger so there is more contact time with the water. I like the fact that I was able to have it outside the sump so I could have more room in there. Plus I have to disconnect the power on the skimmer when I empty the collection cup, and if I dont empty it it can overflow onto floor (however with as dry as it is running...I cant see that happening)

I had my ASM in my reef tank before getting the hydor. It is hard to say whether or not it is more effective then the non-recirculating one. The hydor was definately MUCH more expensive then the ASM