Newbie has questions on plumbling

[new2koi]

Haven't built my pond yet but refining my plans and getting everything straight ( well trying too ).
My question is this : can I tie my skimmer plumbing into my bottom drain?

Think of a rectangle with water flowing from one end to the other were the bd and skimmer is located. My filter is made up of 3 55gal barrels and has 3" pipe connecting them together. The first barrel however is my vortex and has only a 2" intake from the bd pumbing. Should I go with a 3 or 4 inch bd ? I think Im lost on flow rate with the bd being a min of 3" then constricting down to 2" then back to 3". So whats the thought on that? Then can i tie my skimmer that is 1.5" to the bd plumbing?
The reading I've done says that the skimmer bypasses the filter but I like the idea of filtering everything and it would be easier during construction.

I've read enough on this forum to know you guys will be "Brutally" honest, just remember Im a newbie and if I didn't have stupid questions chances are I'd be doing something I'd regret or have to change later.

!!SPECIAL THANX to everyone, making this a first class knowledgable forum!!

[koiczar]

I WOULD NOT recommend tieing your skimmer line to your BD line ANYWHERE! BTW, is there a reason you can't run 3" from your BD all the way to the vortex. Actually, you'll restrict the flow too much from your BD if you use 2" and your pump will draw down you vortex faster than the water can enter. Not too good an idea there. I would recommend a much larger vortex if you can fit it into the plan, or else split the line into two 2" going into separate 55gal drums for settling. I would also suggest using a separate pump for your skimmer. It doesn't need to be large (depending on your pond size ans skimmer being used). You could pump it through a bead filter and return the water through the tpr's.

BTW, just how big is this pond you're planning to build? A detailed explanation would certainly help folks provide you better feedback.

Mike

[new2koi]

thanks for the reply....
The pond itself is only 2500 gals, . I wish I had the room and funds to build one that could compete to the ones I see here but at this time it can only be a dream.

[jnorth]

With the pond being only 2500 gallons I think you could tie them together if you really wanted. I just wouldn't do it the way you are planning. I'm guessing you are planning on pulling the water through the filters so unfortunately the best way to go would be to put a 3 way valve(jandy valve) after the filters but before the pump. You would plumb the skimmer into that and with the valve you can adjust the flow from each side. Make sure you have a pump big enough to handle both sides. It wouldn't be filtered but it would just be using one pump. You could always build a single bio filter (in addition to the ones you already have) to push the water back through to return to the pond. With all that said you should do what Mike said and run two circuits with two pumps. You'll be better off in the long run that way.