Rock and Gravel Types to Avoid?

[Boscovius]

In planning my natural swimming pool with upflow bog filter, I have become aware of the expense involved in the stone that I will use for my gravel bed. Is there anything I should know about which types of gravel media to avoid? I live in limestone country and crushed limestone is very inexpensive here. Crushed concrete is also a very affordable option. I would like to use the least costly options for the deeper parts of my gravel bed and save the last few inches for the decorative colored field stones, river rock, and pea gravel.

Pumice is another inexpensive option that comes to mind and attracts me because if it's porosity, but I have no idea as to it's compatibility with an organic swim pond.

I want to avoid introducing any material that will leach undesirables into the water to the detriment of the organisms I am trying to foster.

Any advice is much appreciated.

 

[GBBUDD]

3/4" RIVER ROCK OR 3/8" PEA STONE PERIOD. IT'S MORE ROUNDED EDGES over type of stone

 

[Lisak1]

I would like to use the least costly options for the deeper parts of my gravel bed

How deep is "deeper"?

And don't expect those two types of gravel to stay separated - they will quickly get mixed together if there's any kind of foot traffic.

 

[Sisha]

In planning my natural swimming pool with upflow bog filter, I have become aware of the expense involved in the stone that I will use for my gravel bed. Is there anything I should know about which types of gravel media to avoid? I live in limestone country and crushed limestone is very inexpensive here. Crushed concrete is also a very affordable option.

When we built our house we used crushed limestone all around to avoid the boggy clay, when I built the pond the wind would whip the stone into the pond and I had lots of trouble with very high alkalinity, it took years to settle down. And that was blown in. I wouldn't use concrete either as it's also alkaline.

 

[GBBUDD]

A PH OF 8.5 IS ALKALINE BUT IS FINE FOR OUR PONDS. ph is more an issue when it fluctuates quickly over a high or low ph