Gravel level with respect to laterals: TR140C Penair Sand Filter

[Ron Stordahl]

I am installing a Pentair TR140C which specifies 275# of 1/4 to 1/8" dia pea gravel. What I find is that, when wet, this amount just matches the height of the top of the laterals. Is this the right level, or should be laterals be covered to perhaps an inch or should they be exposed? The sand will go above this obviously, leaving the needed free board of 13.5

 

[duraleigh]

Pentair can verify the height. I chose not to use ANY gravel in mine ( 9 years ago) and it has functioned just fine. (it was a TR-140....not 140C) I don't think the exact amount is really critical but pentair should be consulted.

 

[patrick3229]

I have a follow up question what is the advantage / purpose of using a pea gravel layer with sand vs. using all sand with no pea gravel?


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[duraleigh]

what is the advantage / purpose of using a pea gravel layer with sand vs. using all sand with no pea gravel?

I don't want to hi-jack the thread from OP but it seems to be a way to get more flow directly around the laterals.

 

[Ron Stordahl]

I got an answer from Pentair, but in case others wonder about this I am providing their answer.

They said that the pea gravel is used to aid/protect the laterals. Having it just slightly above the tops of the laterals is fine. This required 275# of 1/8-1/4" pea gravel, exactly what the spec called for.

I have added pool filter sand above, 650# of it, which provided 13.5" of free board from the top inside of the unit to the top of the sand surface.

In this configuration the unit is working well, with a pressure of 12 psi and flow rate of 110 gpm.

Hopefully this information will be useful to another reader of this forum.

 

[patrick3229]

Thanks guys this is really helpful information.