Underwater Sealant, 290 ml, Black

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!

Great product never fails

Have used this on various parts of my koi pond setup. Sealing permanent joints in various pipework and filter fittings. As I say it sticks to anything. gloves are a must! This time it was fibreglass to stone joints on waterfall that had opened up and was leaking. Don't try to use on anything you may want to take apart at a later date. I do find that unless you seal an open tube very well and come back to it a month or two later, it will have all set! So the 290ml cartridge is not that economical if you just need a small amount. The one-shot tube is as it says. 'one-shot' So hence the 1-star off as I'd like to see a small say 100-150 cartridge tube that could be less wasteful. I see other comments on the clear version that says it's not so 'good' I have only ever used the black so could not comment on that point. It is expensive but does the job!

Very good sealant and easy to use

Absolutely amazing it repaired my pond liner after it got torn near the bottom gold seal made a under water repair I can definitely recommend.

Cannot recommend this enough....fantastic life saver and well worth the extra cost. My juwel corner aquariums (190 litre) pump/filter box simply came away in my hand during cleaning, I have 5 large Severum fish in there (1 is huge) who left me baffled as to how to fix the box back onto the glass in the corner. This is a heavy old long black plastic box with 6 media sponges in. Simply emptied tank half down, cleaned glass both above and under water level as best as I could ,had already taken out box and media’s so added large blobs to 2 sides of the box, all the way down, submerged the large box back into its position and held tight for a few mins and hey presto! Brilliant. I did leave it alone for about 40 mind and kept checking that it wasn’t sliding at all as it sits in the tank with about 3 inches below it. It didn’t move, even when the box was half full of water. Simply put back all my sponges carefully, re-filled tank and done! All fish alive and well 2 weeks later, box hasn’t moved an inch! This has proved to be a real life saver, I don’t usually do write ups but not only was it superb but I couldn’t find many aquarium uses so here I am. Thanks for reading, hope it helped?

As described except came without application nozzle. Annoyed I had to find one.

We used this on the outside water feature which had cracks init worked great sealed the cracks and the leaks are gone would recommend

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

stuff is legit

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.

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.