100% drain into skimmer

[fritz]

I think the "T" just being there allows the air to escape and prevents surges / air from messing up your flow. I'm reminded of the RC Thread of the month from a few months back where the guy advocates turning down your drain via a ball valve but leaving your return at full blast (I think that is F'in nuts.) He claimed that if you got it right you'd match your drain flow to your return flow and get no air entering the drain. You had to make your drain stockman and not durso if I remember correctly.

I'm going to try to plumb mine exactly like that. 95-100% of the flow going into the skimmer but the "T" there for air and excess water to drain from. That's my goal anyway I'll see how realistic that is. It may need to be more along 75-85%.

 

[Wes]

that was my plan as well...but just cracking open the t line to release air made god aweful burping noises....i just closed it completely and get steady flow...there are a few air bubbles but it is mostly water...

I think the deltec AP600 has such a small inlet that the reduction from the drain keeps alot of the air out...If you look at my drain coming from the tank it is completely water w/ a few stray bubbles here and there...Not enough to give me surges or mess up performance...

I am sure it is a case by case basis...Just explaining how it worked out for me...the Eheim 1250 is a perfect match for the AP600. I took the T line off because it just wasted space and was not used.

 

[Wes]

oh i just remembered the only downpoint i can think of...

without a t you have to be carefull of sticking objects in the tank...the water displaces in the skimmer and can overflow it...

Not a big deal for me because i keep the skimmer in sump. I just turn the skimmer off before placing anything in the tank...worst case, water rises out of the top of the riser tube and spills back into the sump...It only does this when i am floating a lot of bags, etc.

 

[fritz]

Ooooh, that is a downside. I can see myself doing that constantly! hahaha
Glad to hear that the 1250 and AP600 match so well that's exactly what I'm going to be using. Hmmmmmm.

I've also been trying to work out in my head how to fit all that in my setup. My display is only about 23.5" above the bottom of my sump which doesn't give me much room to fit a T and ball valve before I'm at the height of the skimmer inlet. The T is also recomended to be at a height that is greater than the top of the skimmer. Impossible to do in my situation.....unless I cut out the bottom of my stand.

 

[Deanos]

Glad to hear that the 1250 and AP600 match so well that's exactly what I'm going to be using. Hmmmmmm.

How are you guys discussing "matching pumps to skimmers", without taking headloss/differences in plumbing into consideration? It could be misleading to readers of this thread.

 

[fritz]

Eheim pumps come with secret decoder rings....

I always use ball valves on my return pumps. I've never seen a pump that will pump X number of gallons per hour forever. Pumps get dirty, pipes get dirty and sometimes I decide to change my mind. It's much easier to make a slight adjustment to a ball valve than search the internet for a return pump that will pump exactly 133 GPH with head loss etc.

For what it's worth I planned on running the Eheim 1250 at about half power and will increase or decrease as necessary. Of course everyone's setup is differnet.

 

[Wes]

How are you guys discussing "matching pumps to skimmers", without taking headloss/differences in plumbing into consideration? It could be misleading to readers of this thread.

the 1250 is rated for 317 gph...the ap600 has a recommended throughput of 160 gph...

with my head loss it works out perfect...i never measured how many gph is coming from the drain. just know that the water level holds steady where it should.

 

[Wes]

here is a pic of mine...

 

[cali_reef]

Fred, let me know if you need a 1250 to try this before you buy one, I have one I was going to feed my AP701 with but instead I am gravity feeding it right now.

 

[TimberTDI]

I'm assuming this only works on a recirculating skimmer?

Steven

 

[fritz]

Thanks Cali but for some reason you and I only have conversations on the days that I'm visited by the UPS guy. My Eheim was delivered today

Thanks though.

 

[pecan2phat]

I gravity feed my AP702 and I'm the only guy that achieves surges within the skimmer when I tee of the feed line so I feed 100% off a connected tank

On the AP600, I found a Mag 2 to be perfect as a feed pump.

 

[jejton]

Sorry for resurrecting an old thread but I was wondering how Fritz's ( I know you broke it down recently but in the past year ), Wes and any other's experience has been with gravity feeding their skimmers. I'm looking at skimmers for my new tank now and am considering gravity feeding as I plan on relying on PH's for flow and would like to keep electric usage as low as possible. I haven't decided on a skimmer yet ( its a 65 gallon tank w/20 gallon sump ( nominal ) ) but so far am looking at Octopus and a couple of others.

 

[fritz]

Gravity feeding a skimmer is a must do. Think of it this way, the most protein laden water in your tank is at the surface. Your Overflow is a tool that skims that utmost layer of water right out of your system. It then dumps that water wherever you plumb it. Now you could plumb it to dump that protein laden water into a protein skimmer, or you could have it dump that water into a sump. If you dump it into a sump you're then mixing the water up and a good amount of it will flow past the skimmer, never having been skimmed.

Not gravity feeding a skimmer is a total waste of one of the best tools we have, an Overflow.

I always found better results gravity feeding vs. pump fed and strongly urge everyone to try it.

 

[Pseudo]

Actually that's not totally correct Fred. It also depends on the flow in your tank. Low flow tanks have a slick surface. Tanks with more flow do not have this "slick" because of the turbulent nature of the water flow.

So, my overflow has the same amount of nutrients and DOC's that the rest of my tank has. So for me to gravity feed my skimmer would be fruitless. Any skimmer sized correctly for the bio-load in your tank and for the accumulated matter in your tank will eventually get skimmed out anyway. If it isn't, then as the immortal SPS Pimp used to say "You need a bigger skimmer". I also feel that a higher flow through tank and sump servers more purposes than to just feed your skimmer.

Smaller tanks benefit more from direct skimmer feeding from overflow than a larger tank does IMO.

Kasei

 

[fritz]

No one has any idea how quickly proteins float up to the surface or perhaps more importantly, which exact compounds do float up. The natural ocean always has a film at the surface in fact at it's most turbulent is where these proteins are most visible and always at the surface. I don't think it's safe to assume that a tank with 80x turnover is homogeneous. In the chemistry and culinary world, mixing liquids up doesn't necessarily guarantee that it is a homogeneous mixture.

By your example, a gravity fed skimmer in a high turnover tank would show no difference if the tank's drain pulled from the overflow, mid tank, or bottom. While that may be true I don't think there is any more evidence that it is, than that it isn't.

Anecdotally, there are numerous examples on most every forum of users claiming improved performance by gravity feeding skimmers. I personally saw an increase in three skimmers gravity fed vs. sump fed. I also messed around with sump fed but at different distances from the drain with and without filter sock. There are just WAY too many variables to get numbers that mean anything but I'm pretty convinced that even in a high turnover tank gravity fed beats sump fed.

 

[Pseudo]

No Fred. The most turbulent water flow is actually in the deeper ocean. The waves crashing up from a surf is what causes the foam akin to a protein skimmer. The easiest way to check your theory is to put water collected from the top of the tank in a jar and some from the center and some from the bottom of the tank. Shake them all vigorously and see what happens. You will probably see no difference whatsoever. Now do the same in a tank with very little flow and scoop up the film from the top of the tank and the water will foam up. Why?? the answer is clear. There would be an abundance of build up where it was allowed to accumulate at the waters surface because there was inadequate water flow to disperse it into the entire water column.

Low flow tanks allow the "visible scum, slick" to gather at the surface of the tank. Meanwhile in high flow tanks you will not see this. That is not to say that the same amount of organic matter does not exist in the same bodies of water. I have seen tanks with low or no flow (water movement) smother the entire tank with the buildup of waste matter in no time at all

The slow flow theory that you make is not an absolute one. Like I said. If you were to put an undersized skimmer on a tank where every drop of water flowed through the skimmer, the skimmer would still not be able to keep up with the production demand of a fully stocked tank with a heavy bio-load. It's also about a matter of contact time, skimmer type and volume

This is why when people put super sized skimmers on their tanks they stop working after an initial rush of cleaning and then nothing. Also when gravity feeding skimmers, once you get the skimmer fed properly where there is less turbulence from the water being fed. The skimmer will produce a much more constant and steady foam head production. The problem with in sump skimmers is that if the sump is not built properly and a constant water level is not kept, the foam can and will break down before anything can reach the inside of the cup.

Perfect example of skimmers that work best when gravity fed are Deltec skimmers. Once they are set you don't need to touch them again unless you just like to fuss with things. Beckett skimmers are the worst at trying to control and are definitely not set and forget it skimmers. But once again if you are proficient at tuning a beckett you will get way more skimmate from them than from a re-circ/needle/mesh wheel skimmer any day.

Gravity feeding is a great way to feed a skimmer without the use of a an additional pump (less power and less breakdown). It gets the main tank water directly to the skimmer to be cleaned (good but not perfect) and it saves on plumbing

I would rather have a filter sock catch most of the larger particulate matter first, then have the skimmer deal with the minute particles and DOC.

PS: Where is my food man ??

 

[Pseudo]

Hey Fred stop swimming in Sheepshead Bay water and maybe you will see cleaner water at the surface. NY water sucks and has more pollutants in it than anywhere else in the world except India

Kasei

 

[fritz]

All very valid points! I like large chunks in my skimmer. I've done the filter sock thing but I worry that if I slack on changing the sock large chunks will break down even quicker in such a high oxygen environment.

As you explained though, there are many roads to the same place. It made me think of tanks that are setup each way that you outlined, that all look fantastic yet use different methodology for dealing with waste. Also as you explained each way has it's ups and downs and suit the user's personality differently (tinkerers should use becketts).

Your food is in my basement waiting for you to swing by.

 

[Pseudo]

I will be back in the states on the 9th. I will swing by on the 10th. So hold it for me. Enjoy the holidays and Happy New year!

Kasei