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I have experie4nce with the RPE liners, great strength and good enough for just the protection (not 100% water tight), but they float.
ahh… didnt know the RPE liners float, but yes, I wouldn’t worry much at all about the large cats and other fish without teeth in the liner tank. Ive had cat arms poke right through intex pools stock liner but that was on the sides with nothing behind it. Never had a problem running an intex with additional epdm over top. Even if an arm does poke the liner its not going through since its a solid back on the sides and bottom in ur pond/tank.wednesday13 Thank you enormously Russ. Yes, I agree about absolutely no biters on rubber. What about no pacu, no distichodus, just the biggest cats, firewoods when they grow up, arapaima, maybe barramundi and nile perch when they grow up, m.b. temensis?
I have experie4nce with the RPE liners, great strength and good enough for just the protection (not 100% water tight), but they float.
That does worry me having that air gap behind the liner than enables an object (cat arm) to pierce through. Under normal circumstances with solid ground or wood behind the liner i would keep ur line up of monster cats in there yes. Sadly i think it will be a mess to try and add another liner in the tank while its full, esp alone. Any chance u can get the window in ur new acrylic tank to empty out the “pond” for reinforcement? Only other idea i can think of is to use rubber cattle mats to lay over the areas u know have air gaps. Theyre sold at tractor supply/feed type stores. Usually come in 4’x6’ sizes 1/2”-3/4” thick. U could lay one at a time like giant tiles lol… no need to weight them down or worry of them moving either. I think u could tackle that by urself. They should be easier to move under water. Each weights around 40-50lbs.wednesday13 So in theory you are saying you personally would place 4ft paroons, jau, sperata, piraiba, rtcs, hybrids, firewoods, large perch, etc. in a single layer epdm rubber liner pond? That is, you'd not even worry about a protective second epdm layer?
99% of the liner in our 25K has a solid plywood or wood board behind it but in several spots there is nothing behind and the liner is stretched - these are the dangerous spots.
IMO, Larger the cats, larger the arms… more blunt of a penetration point. The small guys are the dangerous ones with needle like arms. This is a tough one tho, the more info u give with the poles and foam supported spots is a bit worry some. Might just have to try and protect as much of any problem areas as u can and release the beasts lol… Starting to come to the same conclusion as you, with just throwing another liner over top. Thats a tough job with a full tank, both of fish and water. Maybe doable with rolls of 6’-8’ wide liner for example. Might be cheaper that way and u can even double or triple up anywhere u think could be more likely to fail.wednesday13 Thank you so much for your continuing, experience and knowledge based help. Very much appreciate it and grateful.
So what you are saying, I think, is that if there is a hard solid surface behind the rubber liner, a catfish spine can only penetrate the distance equal the rubber liner thickness, that is 45 mil, and this will leave only a pinhole, and pinholes don't leak. Is this what you are saying? Why wouldn't a pinhole weep water?
There are 5 layers of 6 mil greenhouse plastic film protecting our rubber liner all around from the outside elements - roots, rocks, sharp coral chips, sharp gravel, etc.. So that's another 30 mil of penetrable depth for a stab.
There is half a dozen vertical 4x4 posts inside the pond behind the liner with the liner wrapped around them by water pressure, and this is where there are narrow vertical places with the liner unsupported from behind. Where the posts meet a wall. IDK if this makes sense, hard to describe, easier to drawEDIT:I also just remembered that I placed some styrofoam in the two bottom back corners to fill them up a bit and smooth out the corners a bit. These would be the weak spots too.
So if you'd only were concerned about these narrow vertical portions of the liner, they perhaps could be protected far easier than all of the liner, but not by cow matts, which in your picture were laying flat on the bottom, I assume.
There are also folds and wrinkles in the liner, from a few inches up to a foot wide, many run for 20-50 ft distance. Would this concern you (in the case where you solved all other problems and left the rest of the main liner unprotected)?