Installing HDPE in Bare Bottom Tank Questions

[Fish Fan]

Hey all! I recently picked up an IM Nuvo Fusion AIO 25 Lagoon to be a coral and motile invert QT/Frag tank (fishless) to support a 150 display that I just ordered

For a lot of reasons, I want to go bare bottom here, please don't try to talk me out of that lol ;-)

I ordered a piece of 1/4", black, HDPE to put under my rocks,

My question is, should I just cut the HDPE material to fit, put it in the tank, and then pile my rock on it? (I read that sometimes the HDPE floats?)

Or, should I try to silicon seal this in some way? I consider myself pretty good with silicon, but I DO NOT want some amateur looking silicon seam on the bottom of my brand new IM tank.

Plus, I don't want detritus getting under the HDPE plate, nor do I want critters like snails and crabs to get under there.

What do you guys suggest here?

Please know, I already have the IM Nuvo 25 AIO tank, and I already have the HDPE material. And, this is not my display tank ;-)

Any help or suggestions would be much appreciated!

Thank you in advance!

 

[polyppal]

I don’t silicone it down when I’ve used starboard in the past, with the rock on top it’s fine, and there have been times I made a mistake and would’ve been in a world of hurt if I had adhered it

 

[Fish Fan]

No worries about critters getting under there?

 

[dpoltsdsu]

I’ve used it and just stacked the rocks on top and it wasn’t an issue for me! I didn’t silicone it or anything like that

 

[polyppal]

No worries about critters getting under there?

Not as long as you’re starting with a clean bottom

 

[MoshJosh]

All my tanks are bare bottom but I just put my rock directly on the glass (keep in mind I use flat bottom rocks/base rock primarily). So for me I would skip the HDPE. If I HAD to use it, I would consider cutting it to the shape of my base rock so there was only plastic where there was rock. While I like the idea of siliconing it down to keep critters and detritus out, I fear the silicone will not adhere properly leading to its eventual failure (not really an issue as the rocks will hold it down but still sort of defeats the purpose). Also, keep in mind plastics can expand in water. I’m not sure how much with HDPE, but something to consider when you are sizing it.

 

[helmsreef]

Silicone won’t adhere very well to hpde, it’s usually mechanically installed. Any silicone you use will either not adhere or come off shortly down the road so just lay it down under your rocks.