The deciding factor to me in determining which bog to build is by answering a couple questions.
Are you going to have koi? goldfish? tropicals ? if koi i recommend the aquablocks as koi get real big and even when they are small the eat a lot and poop even more. Not that the pea stone can't do the job, its that the more and the better the filtration the GREATER THE ODDS OF SUCCESS
Are you ok with ten fish in the pond or do you like the idea of all kinds of color swimming around? Again if the answer is lots of fish and color then the aquablocks is my suggestion.
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@Jhn I have two bogs but one of each as the pea stone bog is a backup it runs 24/7 but I had to rebuild the main bog only because the original water fall was less than a foot and it was lacking pizzazz and i did bump up the gravel to about 30" I HAVE NOT HAD TO CLEAN EITHER of them but the aquablocks do more than just be an area for clean out.
Any heavy solids that get pumped down there will settle out of the water and drop to the bottom of the blocks this does keep the gravel from getting clogged or blocked up and in the settling area the this acts as a cave that's protected from predator's and allows bacteria, microbes, and insects a home with a smorgasbord dinner table. The water is then disbursed and lifts into the stone cleaner than how it entered and all we have done is taken away water flow and pressure. you don't get that with the pea stone.
also the longer the water is underground the cooler it can get which is great for summer temps'
So is it worth the extra cost? to me yes. can you do without it ? yes
Most here will also suggest what ever your filter is rated for to take away about a 1/3 and that's the real number the filter can effectively maintain.
a cistern is a way to go green with the pond by collecting rain water. food for thought.