crsublette
coyotes call me Charles
Yeah, you'll appreciate the extra time you put into design and the extra filtration in case you ever want to do anything crazy with the volume of fish in your pond.
I think an extra mechanical filter after a skimmer is probably unneccesary, but I would do it since S&G filters are too simple to not do and very easy to maintain and can be buried without worries.
I have heard of bottom drains, depending on its design, are able to suck in small fish, small frogs, etc. Look into the anti-vortex designed bottom drain. I am still reading about this so don't know much of it, but it might be something for you to look into. Since there is that possibility of small fish able to swim into a bottom drain, then you might want to think of pre-filtering after the bottom drain such as a sieve filter or a settlement chamber before the water enters the bottom of the S&G filter. I have seen bottom drain water being pumped directly into a S&G without any pre-filters and I have seen acorns, leaves, and twigs being flushed out of the S&G when the S&G is being blown, but this is not to say it takes everything that might get lodged in the S&G. Something to think about at least.
Be sure you properly mechanically filter the debris before it has the chance to accumulate in the bio-filter. At this moment, it is my understanding that most of the beneficial bacteria live in the top 1.5cm layer of debris or organic matter on the ground or on the filter media; physico-chemical factors and bacteria in fish ponds is a good read to give you a perspective on the matter. If the debris accumulation becomes too thick, then oxygen saturation is reduced causing your bacteria to be dead or less efficient.
As I mentioned before, there are quite a few people who just do simple, whatever that will work, and is happy as long as their fish are pretty and alive. Since you are considering a bottom drain and water currents with pond returns, this is a step further than a common pond setup will implement. I am not for sure what the flow rate would be out of pond returns to create a good water current, but I think you do not need much flow to achieve a simple current to consolidate the debris toward the bottom drain.
I think an extra mechanical filter after a skimmer is probably unneccesary, but I would do it since S&G filters are too simple to not do and very easy to maintain and can be buried without worries.
I have heard of bottom drains, depending on its design, are able to suck in small fish, small frogs, etc. Look into the anti-vortex designed bottom drain. I am still reading about this so don't know much of it, but it might be something for you to look into. Since there is that possibility of small fish able to swim into a bottom drain, then you might want to think of pre-filtering after the bottom drain such as a sieve filter or a settlement chamber before the water enters the bottom of the S&G filter. I have seen bottom drain water being pumped directly into a S&G without any pre-filters and I have seen acorns, leaves, and twigs being flushed out of the S&G when the S&G is being blown, but this is not to say it takes everything that might get lodged in the S&G. Something to think about at least.
Be sure you properly mechanically filter the debris before it has the chance to accumulate in the bio-filter. At this moment, it is my understanding that most of the beneficial bacteria live in the top 1.5cm layer of debris or organic matter on the ground or on the filter media; physico-chemical factors and bacteria in fish ponds is a good read to give you a perspective on the matter. If the debris accumulation becomes too thick, then oxygen saturation is reduced causing your bacteria to be dead or less efficient.
As I mentioned before, there are quite a few people who just do simple, whatever that will work, and is happy as long as their fish are pretty and alive. Since you are considering a bottom drain and water currents with pond returns, this is a step further than a common pond setup will implement. I am not for sure what the flow rate would be out of pond returns to create a good water current, but I think you do not need much flow to achieve a simple current to consolidate the debris toward the bottom drain.
