Underwater Sealant, 290 ml, Black | Aquarium, Pond Liner Sealer, Bonds and Seals Leaks Underwater

stuff is legit

Works well and cures underwater… fish in tank weren’t harmed. I recommend using latex gloves because if you get this on your finger it will be all over your body before you know it.. lol

It is too early to comment on how well this product fixes the leaks on my backyard pond as It is only 2 days post installation. I’m commenting now to help others as they consider this product who may be concerned about multiple reviews stating how messy this product is. This was a concern as I considered the pros and cons of the purchase. This product is no more or less messy than any type of adhesive caulking I have ever installed. Of course if you are not careful it can be a problem. Simply take your time to get the nozzle cut to the volume you want to apply and then run your bead accordingly. I found the info online adequate to understand how to prep and apply the product. If the product performs as specified I wil change the review to 5 stars.

The black stuff seems to be holding the rubber patch So i can give it a 5.

I used it to fill a crack and a silver dollar-sized hole in a cement pond. I didn't have to remove the fish or empty the pond. The stuff is messy to use, but if you have experience using epoxy grout or clear calk, there won't be a problem. The pond holds water, and the fish didn't die. Success! I can't comment on using it on pond liners. however.

I bought this sealant to patch a hole in my koi pond liner. I attached the patch with the sealant, refilled the pond, and promptly had a leak. Upon a second disassembly, I noted the patch had failed completely. The product states it can be used under water, yet the label states it must cure 24 hrs. I ended up using another product, liner seam tape, to remedy my hole.

Great product worked in pond

I buy a lot of stuff on Amazon, but this is actually the first time I am leaving a review, because this product is that bad! Please do not purchase it, it is a complete waste of money and it does not work. This product works almost the same as the $9 silicon sealants sold at Home Depot, and trust me, with a sizable pond, this little amount of sealant will not kill your fish. This product is also very expansive because it claims that it works under water. It does not! There is no way you can get it to work underwater, trust me, try it if you don't believe it. So I ended up draining the huge pond anyways, and applied this product. But it does not work. Pond still leaks a lot of water. This thing probably can't stand the UV rays from direct sun light anyways, and looks like it will degrade give it time even if it stopped the leaks. So if you have a "mason/concrete/plaster" pond like me, good luck. Your best bet is to change it completely into a liner finish (rubber) base, or find a swimming pool company to do it properly and spend the extra money, because they do it properly with thick concrete and big foundation like a regular pool. Otherwise the pond will crack with time, and this product will not help you! Simply DOES NOT WORK!

I have ordered several of these, over the years, I like to keep one in, as I have a pond with a butyl liner, this stuff is brilliant, says what it does on the tube. It's got me out of a scrape, when rats have chewed my liner a few times. Speedy and safe in the water with fish. Easy to use ,but I would recommend gloves as it sticks really well.

It did exactly what they said it would do, and it solved my problem I thought I could not fix

This product is amazing and I wish I discovered it sooner. My pond has always had a slow leak since I bought the property and it was already there and it was annoying, but I lived with it. However recently I was working by the side of the pond and dropped a saw which tore big jagged holes in the liner.... I was mortified and the level dropped by half within hours. After lots of research and not much luck and almost resided to the fact I was going to have a mammoth task ahead redoing the pond, I discovered this product. Skeptical but I tgought for the price, worth a shot. Amazing. Easy to apply, does exactly what it says on the tube and whilst I did it, I went around and covered a few tiny holes at top and pond is the fullest and best it's looked since I have moved in and staying full. For the large holes from the saw teeth, I bought a tiny pond liner from here, which was cheap and cut a small patch, like repairing a bike tyre and it's worked a treat. £20 spent in total and pond like new.

A very good product and has worked to seal the holes in my pond, however anyone who suggests this can be used under water must have strange mystical powers enabling them to do so. I tried using it under an inch or two of water and the sealant just floated away like a sea slug. However, definitely works a dream on fully drained pond even if surface still damp.

Although the stars above do not reflect how good this stuff is it is a life saver! I have a very large koi pond that had 2 big leaks, one inside the filter box where I had to do a modification and one inside the plastic skimmer which is part of the main pond itself. I used this silicone to put a complete layer over the filter leak, and pretty much the same in the skimmer, my water loss has gone from around 4 inches of water per week to zero, if this hadn't of worked I was looking at a complete overall of both pond and box. Value? It is very expensive for what it is, I work in construction where there are specialist products for half the price so unless you definately need this look else where! Also ease of use! Not at all, wouldn't fancy trying to get it to stick underwater? It was hard enough to get it off of your fingers when dry! Having said all this IF you are at the last option you won't go wrong by buying this stuff, I went straight for black bigtube!