lets talk skimmer water depth height

Fluid is fluid, mass is mass, air and water are exactly the same. Mass x acceleration is force.... force over distance is work, work over time is power. When you take the door off a AH, air flow increases... it either now has a place to blow out and bypass duct work, or it has a place to suck in unrestricted by filters. Air flow increases, power use increases. Glad you have seen this first hand.

Just because a fan overheats, does not mean it is over amping. It could be that you redirected cooling flow across the motor... or it's over amping moving more air.... over working.

I'm not a HVAC guy... but physics is the same for you as it is for me. 25 years in the power industry starting with Naval Nuke Power school pretty much explained it for me. Yet to find a flaw in the equations all this time. Heat transfer, fluid flow, power conversions have not changed. Ask any Mechanical or Electrical engineer you may know. You don't have to take some guys word for it on the internet. Just look into it. You'll learn something new.

A simple wiki search will help you. Just study power use, fluid flow, and work. All the equations are there for you.

 

Wow great thread. I totally thought that this thread would die in a matter of minutes but boy was I wrong. This information is incredible and provided a good read for me.

 

Well, I followed you until the side note. I remember Bernoulli's principle and that water is not compressible, air is etc.. but I'm not sure I'm putting it together correctly. Let me know if this is what you are saying. As the pump is effected by less force within the skimmer column, there is more energy available to perform work. However, the pump throughput is then limited by the physical size of the pump, as the water cannot be compressed to fit through the body and nozzle of the pump, creating a restriction. There is however enough energy available, due to the reduced force in the skimmer column, to create a larger pressure differential when air is allowed in. This is because the the air can be compressed, allowing more air to enter the pump, and therefore perform more work than if the pump was moving water alone.

Close?

 

Sounds feasable...
But is there any relation between the difference in pressure as water travels from high to low through the pump and the pressure that the air is compressed at?
What I'm getting at here is this: if you maximize the pressure difference for water between in and out of the pump, how will this impact air flow?

 

If what I said is correct, then the pressure differential results in more air flow. This is because the flow of water is restricted due to the physical size of the pump, but the air can be compressed, so it is less restricted and more can be pulled in to fill the void.


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Sort of, not really. Sorry if I threw you. All I meant was that pump performance is easy if we are just talking water. But since a skimmer pumps job is to pump a air/water mixture, it is a bit different. And part of skimmer performance is based on how much air it can draw and what the air/water ratio is. So all I meant was that small difference in head pressure make big differences in air draw. An inch of level change in my skimmers would change air draw a lot.... like 10-15%. Where as a inch of head pressure will have very little effect on out put of water.... certainly not a 10% GPH reduction.

So like usual, if some is good more has to better right? No... you lower the skimmer all the way, your process more water and draw more air, but then you limit chamber size and can't control water level.

A lot of stuff about skimmers is about balance. It isn't as simple as some cookie cutter thing... you do this and add this and cram as much in as you can and everything is better. No. One thing effects another thing which changes everything else. So it's a balance of body size, neck size, hieght, water through put, air draw, and the ratio of air to water. The range you have is where it will work best... and at the ends of the range, these are the things you will see. Run it how you like undrestanding the compromises you are making.

 

Well now that's a great summation all in one... Now where do you run yours at, I can't remember if you said that yet or not?

 

I moved mine from top of the range to bottom...I always want to know where the fence posts are at. Then I found right in the middle was perfect for me.

 

No worries, it's great to learn about this stuff in more depth. I was just trying to work through the power consumption, water through put and air draw for the momment. I hadn't got to the other stuff and practical implications when applied to the entire system yet LOL.

 

Yes... and who care about theory, if we can't apply it to the real world in a practical manner?

For a sump skimmer section, the baffle, water depth should be set at 10". That depth will acomodate about 95% of the skimmers out there. You can always raise a skimmer up with a stand, but you can't make a sump deeper.

Best results are going to be right in the middle of manufactureres recommendations. They are the ones that designed it, built it, and tested it. But experiment your self to see where you like it for what you want. I never hurts to experiment.

Never flow more water in a system than you need to. The most efficient flow devices are power heads. They move the most water for the least power. Sump pumps should never be used for tank flow. There is a HUGE penalty pumping water up 6 feet.

Only circulate enough water through the sump to supply the equipment in it. If all you have is a skimmer, and it can only process 300 gph, then there is no reason to circulate 600 gph through the sump. Waste of power. If your fuge is seperate from the skimmer section then that will have to be figured in. But there is no such thing as a "proper sump turn over rate".

Power consumption by water movement only adds heat to the system. Everything in the end is reduced to friction and heat. Now some systems need heat. And pump heat is not a bad thing if you run heaters 24/7. However, most of us have to get rid of heat at some point. Getting a pump to supply a chiller to remover chiller pump heat, return pump heat, and skimmer pump heat that is not needed is a big waste of power and money.