100% drain into skimmer

[Wes]

100% gravity fed here...i use an eheim 1250 as a return...keeps my ap600 fed perfectly (rated for 180 gph). It's a perfect match. Approx. 3x the display volume and i have no problem temp or 2-part dosing probs...

Display Circulation is handled by Tunzes...

some pluses are:

Silent overflow
No microbubbles
low energy consumption
100% skimmed water coming back up to the display

negatives:
none that i know of

 

[TimberTDI]

OK here's what I don't understand:

Your skimmer is pushing 125gph no matter what. It's not like your going to be skimming more. You will just be skimming a smaller percentage of water more effectively. Won't it just be a small amount really clean water mixing into a tank of dirtier water? Am I wrong? I don't know what size tank you have tho.

The only gravity fed I've ever seen was one where the person had the water dropping down 2" drain about 16' into a sump. The turbulence from the water crashing into the sump created and automatic skimmer.

 

[Wes]

it is supposed to be a bit more efficient. 100% of the "dirty" water from the overflow gets skimmed. When the skimmer just sits in the sump, you are skimming the "dirty" water as well as water that has already been skimmed.

when 100% of the water from the overflow enters the skimmer, nothing gets returned back to the display w/out being skimmed. Also the water from the overflow is the surface water which contains most nutrients.

maybe someone else can explain it better lol

 

[fritz]

OK here's what I don't understand:

Your skimmer is pushing 125gph no matter what. It's not like your going to be skimming more. You will just be skimming a smaller percentage of water more effectively. Won't it just be a small amount really clean water mixing into a tank of dirtier water? Am I wrong? I don't know what size tank you have tho.

The only gravity fed I've ever seen was one where the person had the water dropping down 2" drain about 16' into a sump. The turbulence from the water crashing into the sump created and automatic skimmer.

You're right and wrong. I guess if we look at it like this:
1. The skimmer will only process 125 gph.
2. At 125 gph a 20 gallon sump (most likely only has 10 gallons in it) will see 12.5 X turnover. Plenty of flow to heat the tank, feed pods etc. A 30 gallon sump (maybe 15 gallons of actual water) will see almost a 10 X turnover, again fine.

So I guess the question becomes WHY would you want to push extra water into your sump that your skimmer can't process? What's the point? Any flow over 125 gph, ESPECIALLY if you "T" it so that it passes by the skimmer, is wasted.

 

[meschaefer]

OK here's what I don't understand:

Your skimmer is pushing 125gph no matter what. It's not like your going to be skimming more. You will just be skimming a smaller percentage of water more effectively.

You won't be skimming a small percentage of water, you will be skimming the same percentage of water, because the amount of water entering the skimmer doesn't change.

Won't it just be a small amount really clean water mixing into a tank of dirtier water? Am I wrong? have tho.

Once again, you are processing the same amount of water, so the tank water won't be dirtier. The reason you skim water from the top of the tank with an overflow, is because dissolved organics collect at the water surface for the same reason that they collect on the surface of the bubble in the skimmer-surface tension. In a standard set up most of the water entering the sump, does not go through the skimmer. Lets say you have a 100 gallon tank, and have 10x turnover. That means a 1000 gallons per hour goes though the sum but only 200 gallons of that goes through the skimmer. That means 80% of the water is sent back to the tank without being skimmed.

There may be reasons that you want to do this. You don't want power heads in your display tank and you are using your return pump to generate flow. But if you don't need the extra flow, and one of the main reasons you send water to the sump is to be skimmed , then this is really inefficient. You are using a large return pump (in terms of wattage used) to generate flow in the tank, when a much smaller one can get the job done in the display tank.

 

[herman]

Get a bigger skimmer

 

[meschaefer]

Will this work.....

 

[MO~IDOL]

This 1 work too

 

[cali_reef]

I think this one is a bit more practical for a home aquarium

 

[fritz]

Seriously now, I use an oversized skimmer already and I don't think a bigger one is the answer. If we use conventional wisdom with our returns and match our skimmer to the return (!?) I would need a 3 Eheim monster from deltec on a 58 gallon tank! As cool as that may be that's not a good idea.

It makes much more sense to pick a skimmer and then match your return pump to the needs of your skimmer.

 

[cali_reef]

You're right and wrong.
So I guess the question becomes WHY would you want to push extra water into your sump that your skimmer can't process? What's the point? Any flow over 125 gph, ESPECIALLY if you "T" it so that it passes by the skimmer, is wasted.

Fred, It is not wasted.. The surface area of the sump provides additional area for gas exchange, evaporation cooling, space for detritus to be trapped or settled, etc..

Again, the water flowing thru the sump also is used to heat and cool the main tank water, slow flow will not be as effective.
You should just get a HOB skimmer if there is not a need to flow additional water thru the sump.

 

[fritz]

It would seem that putting 100% into the skimmer will also cause some fluctuations in pressure. It's hard to keep the flow consistant with all the air that also enters the drain.

 

[herman]

It would seem that putting 100% into the skimmer will also cause some fluctuations in pressure. It's hard to keep the flow consistant with all the air that also enters the drain.

Thats why you need the T fitting. It basically "relaxes" the flow. Put the T as far as possible from the ballvalve that you use to regulae the flow into the skimmer. The farther the better and more constant the flow gets. All the bubbles etc will exit through this.

 

[Deanos]

Thats why you need the T fitting. It basically "relaxes" the flow. Put the T as far as possible from the ballvalve that you use to regulae the flow into the skimmer. The farther the better and more constant the flow gets. All the bubbles etc will exit through this.

Adding a T fitting makes this thread just another "here's my gravity-fed skimmer" thread. Fritz wants 100% throughput :tongue1:

 

[herman]

Adding a T fitting makes this thread just another "here's my gravity-fed skimmer" thread. Fritz wants 100% throughput :tongue1:

The worst enemy of a gravity fed skimmer is surges. Whats the point of having 100% throughput if the skimmer is not performing properly due to inconsistent waterline in the skimmer and turbulence from the Giant bubble that comes through the feed pipe. Ive tried all that. Just does not work very well.

 

[Deanos]

Whats the point of having 100% throughput if the skimmer is not performing properly

Good! That's what I wanted Fritz to hear :splitspin

 

[meschaefer]

Ive tried all that. Just does not work very well.

That's what I was looking to hear (read). First hand experience.

 

[Nsr250NYC]

i've tried that with my g3 before. it surges inside the skimmer making the skimmer useless, i ended up T-ing the drain. unless you make another durso before the ballvalve, which it still doesn't work that well. it's more consistant with a feed pump imo

 

[fritz]

Yeah I talked to Doug at Deltec for a little while about it. He agreed that with a 100% drain fed skimmer you'll never get consistant flow. As Herman mentioned you'll constantly get surges and big bublles etc.

 

[Wes]

i originally plumbed mine with a T...never opened the T line as the pump provided a perfect amount to the skimmer...

I get no surging whatsoever, maybe the low flow cuts down on the surges...works perfect on my Deltec...It's definitely a good Idea to have the T as a just in case, but I got lucky and bought a pump that was perfect match for the skimmer w/ no trial and error.

the 3x turnover is plenty sufficient...no problems w/ heating or cooling here.