Optimal eyeball size and direction

[Redpooled]

I have the following setup: 4 returns, 2 main drains (shallow and deep), and 2 skimmers (shallow and deep). All are separately plumbed back to the equipment pad, which is well below the surface of the pool (down the hill), on the side of the skimmers. Pretty much at the depth of the deep end (10ft). What would normally be an decent setup for the the return eyeballs in this configuration? Direction and size. Is it important to have different sizes given that they are separately plumbed?

 

[PoolStored]

You are asking two questions...

How can I get the best circulation to ensure even distribution of chlorinated water?
How to I maximize the skimming effect in my pool?

Question 1....For the eyes size won't matter, GPM will be the same. Velocity will vary.

As for question 2,.. assuming the north is to the top of the diagram, the NW return should face NNE. For the W return, I would go straight out. The SSW return should face South/ SSW, and the eastern should go straight out. This will likely give you the best distribution of chlorinated water.

The prevailing winds will have a FAR BIGGER impact on the skimming effect than anything you can do with the return eyes.

If your picture has North at the top, prevailing winds from the NW will force detritus to your skimmers. Any other direction, you will have collections in corners opposite the prevailing winds.

 

[Redpooled]

Question 1....For the eyes size won't matter, GPM will be the same. Velocity will vary.

Is that because they're separately plumbed? Will there still be a small impact of eye size at the return manifold? My mental picture is that a smaller eye will increase the pressure at the eye itself, which will increase the pressure all the way back at the manifold. But that is probably a small effect relative to the head pressure which is around 10ft. So there will be minimal difference in flow rates down the different return legs at the manifold?

If only velocity varies, and the above explanation is correct, that suggests using the smallest eye to get maximum velocity and hence the best skimming effect? Or is velocity irrelevant to skimming efficacy (ignoring winds)? If that's the case, it would suggest using the largest eye to reduce the pressure at the pump, since I have a 10ft head already. (Although now I think about it, the head should be irrelevant to the pump since it sees the same head on input and output, and the pump should only "feel" the difference in head between the two?)

As for question 2,.. assuming the north is to the top of the diagram, the NW return should face NNE. For the W return, I would go straight out. The SSW return should face South/ SSW, and the eastern should go straight out. This will likely give you the best distribution of chlorinated water.

Interesting. I will try that. I currently have the 3 W returns pointed NE/NNE, and the E return pointed SW, as an attempt to create a fully "circular" flow around the pool to direct surface material to the skimmers. I have tested how much much my chlorine concentration varies around the pool, and not measured a difference, although that's only at 18 inches depth (and only to the precision of the chlorine test which is not very precise, but presumably because greater precision is not relevant).

The prevailing winds will have a FAR BIGGER impact on the skimming effect than anything you can do with the return eyes.

At least in terms of moving surface debris to the skimmers, this is not consistent with my observations. We tend not to have windy summers where I am in NJ, so prevailing winds are light. The returns definitely circulate the surface water such that the debris ends up in the skimmers, unless it is very windy.

 

[ajw22]

Toss some ping pong balls on the pool and watch the way they move. Actual tests are better than theory. You will find even light surface winds effect the surface flow more then all the eyeball adjustments.

 

[PoolStored]

At least in terms of moving surface debris to the skimmers, this is not consistent with my observations. We tend not to have windy summers where I am in NJ, so prevailing winds are light. The returns definitely circulate the surface water such that the debris ends up in the skimmers, unless it is very windy.

Then a clockwise or counterclockwise circulation should be fine. If you have consistent FC measurements, this should be fine.

The amount of head from the return size should be minimal.

 

[Redpooled]

Toss some ping pong balls on the pool and watch the way they move. Actual tests are better than theory. You will find even light surface winds effect the surface flow more then all the eyeball adjustments.

My observations on wind vs return flow are based on what the leaves floating on the surface do. My pool catches a lot of them. It's certainly the case that wind above some threshold dominates, but at least where my pool is situated, most of the time the skimmers do ok. The pool is pretty sheltered, so that probably has something to do with it.