Thanks for the explanation. I think I get it now. So your snorkel is 12" diameter pipe?
Well, actually, I found the ones they sold at the big box stores to be way too expensive for my needs (I think a 12" diam corrugated pipe/cleanout pc was over $75) so I improvised by cutting out the bottoms of a bunch of square plastic buckets and stacking them until desired height. It fit a pump just fine. Didn't look like much but I was burying it in all that gravel so I didn't care. With bog V2, I used a 30 gallon trash can as my 'vault' because I was going to dual purpose it. This new 'snorkel/vault' is used to grow a pot of yellow flag iris. The bottom is at the lowest point of my bog and I cut large holes in the sides near the bottom so that if I ever have to drain bog V2, all the water will make its way to this point. In V1, the space was just wasted as a water column and it was too small to really put any iris/plant in it, plus was just below the water level and therefore would overflow and bypass the gravel. In V2, I made sure this one was at least 6" higher than my gravel surface to insure no water got out that way. As a matter of fact, I put a T on one of my gravity outlets and send a portion via smaller hose, TO this new iris vault/ snorkel. This gives the iris more nutrients plus will flow down and out the bottom holes and diffuse into the bog.
As a furthering of what I noted above, this is the diagram of what I'm using, if you're interested.
This pic shows how I prefilter using a 50 gallon drum. I actually doubled this when I expanded and now have 2, each of which gravity feed into the bog. This is my V1. In V2, I have the outlet pouring directly from a 1-1/2" flex pipe shoved down into one of (4) 4" drain hoses, which go to the bottom of my V in the bog. This shows how I used to pour into my original 'bucket' snorkel/vault. The 'filter' used inside this drum is actually based on an aquarium concept of a 'sock filter'. Works a charm and magnifies the actual filtering area tremendously. And as noted earlier, takes me literally 5 minutes to turn the filter sock inside out and spray away the buildup, then reinsert into the drum filter. I can vary the micron size depending on how dirty the water seems to be. I have to clean more often when I use the 300 micron size versus the 200 version.
This second picture shows how I split the output of my pump to supply water to both my waterfall(s) and to the drum prefilter. A little known fact is that if you upsize your pump outlet AT THE OUTLET by adding a reducer, it gives you more volume/capacity than if you just used a T later down the line. I went from 1-1/2" outlet to a 3" outlet, then added a Y, then reduced it to the 2 feeds (at 1-1/2" again). A neat little trick that has served me well. I'd have reduced my output to both endpoints if I'd just used a T only.
