adding a raft bed

So Friday Afternoon I went down and picked up the new liner for the bed.

Yesterday, I spent the day installing that new liner.

First I drained the existing liner (involved setting all the grow beds to constant flood to hold the extra water so I didn’t waste it all. I also filled up some other tubs with water to try and conserve. Even so, I of course lost some.

Anyway once the bed was drained down, I tried to clean it out a bit and I cut slits along the outside edge to let it drain the rest of the way and added a few holes in the deep spots and one end. Otherwise I have left the billboard liner in place as and underlay to help protect the more costly EPDM though it is usually tough enough not to need as much protection.

However, this isn’t Firestone Pond guard EPDM and even through it’s supposed to be the same mil, it doesn’t feel as heavy. I’m also a little worried that it smells a lot more than the Firestone stuff I’m used to. This stuff is actually white on one side and black on the other. It was being sold as “pond liner” but I’m a bit worried that this is actually roofing EPDM.

I unfolded it since it wasn’t folded in a way that would easily lay out into the bed. I sprayed it off with the hose hoping that a rinse would help, it smells strong. The ends are also dirty, must have been sitting on a wet floor before getting boxed up.

Anyway, got the liner re-folded and rolled so I could place it in the bed and unroll it as the stays and arches would not let me just drag it in.

Lifting the rolled up wet linger into the bed kinda impressed me, the liner dry was 85 lb so I’m certain that with some of the rinse water still trapped in the liner it must have been more when I lifted the roll up.

Note how the liner is folded kinda like kleenex when I unroll it down the bed.

This is very helpful when laying long liners into rectangular beds. It helps to get the liner roughly centered in the bed and then you simply flip the sides up.

Of course was a little trickier than that in this case since the stays were in the way so I had to cut slits for the overlap of the liner to fold over the outside of the bed.

As I noted, there is a really strong smell to this liner. I’m worried that it might not be fish safe even though it was being sold as pond liner.

So, I didn’t completely patch it back into the main system plumbing yet. I re-filled it half way so I could set the rest of the beds back to flood and drain. And then bypassed the flow to/from this bed so I could keep it isolated for a while.

I have added some test pilots. Two Catfish.

And need some aeration and such so here is how I left them for the night

Since taking the pictures I added a couple 3 foot towers worth of filtration as well.

4 comments to adding a raft bed

  • Richard Martin

    did you use billboards and the rubber liner over that?

    • TCLynx

      I started with a used billboard liner but it leaked so I drained it and cut more slits around the edges so it would not hold water but I left it in place as a sort of under layment to protect the new liner.
      Then I purchased an EPDM liner to place in the bed.

  • John Windsor

    I want to add on a DWC, eventually, similar to what I see here. I think I can get some used billboard vinyl. If it doesn’t leak, is it safe for the fish? And what did you build the frame for your bed?
    Thank you for what you do. I have already learned a lot by reading your stuff.

    • TCLynx

      I wouldn’t build it the way I built this one. I would use fence rails and split T clamps to make the frame and then I would use snap clamps to secure the liner along the top making sure there are nice rounded corners in the bottom so the liner will pull down instead of pushing out.

      The billboard liner, use at your own risk, I don’t know if they are all made of the same stuff. Definitely put the print side down though. Mine all leaked so I us them for wicking beds where a little leaking isn’t that big a deal.

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