Hi, we are new to the forum and are converting pool to a pond.

[CLippincott28]

It has been in operation for about 3 months And fish are doing well and frogs have been breeding.
Building a bog filter and ready to put rocks and pea gravel in. We have 6 inch tall milk crates on bottom. ( I cut them down and fitted them over the pvc piping.)
is there a problem using lava rocks as the middle layer of rocks? Will use 2-3 inch rocks as bottom and pea gravel on top.
Thanks for any input.

 

[Mmathis]

Hello and welcome!

When I first started ponding, everyone was using lava rocks in their bio filters. I have since learned that, while lava rocks do contain a lot of surface area, they are hard to keep cleaned. If those small crevices fill up with gunk, I’m not sure they are effectively serving their purpose. You want surface areas that oxygenated water can pass over.

 

[CLippincott28]

Thanks TurtleMommy, is a bio filter the same as a bog filter and if not would the same issue apply in a bog filter.

 

[addy1]

Welcome to the forum!

It applies to both. They fill with muck.

 

[j.w]

@CLippincott28