Originally Posted by
Surfhead
If you have the skimmer and bottom drian line tie into each other then one will be favored over the other.
I am actually thinking one bottom drain in the main pond won't be enough. Its 18 feet long and one bottom drain will never reach that far. Also I don't think you don't have enough mechanical filtration. Plenty of bio filtration with the two 55 gallon barrels and the bead filter. might I suggest having TWO vortex filters and each has its own bottom drain. If cost is an issue you can make them DIY. OR instead of two vortex filters, add a microscreen to the one you have.
Just having a drain out in the upper pond is fine IMO, just make it easy to drain and do this frequently. Also, shape the bottom carefully so all the muck flows down into the drain. Maybe use a 3" bulk head as your drain to give you a larger pipe and prevent clogging. The other option is to give it is own filter and pump and have the water flow back into itself. This would be the best option as it would increase the amount of filtration on the pond. rigging a split level pond into one pump and filter would be VERY tricky.