Instant Ocean HoldFast Epoxy Stick, Fish Safe 4 oz

Bought two of these little tubes to "cement" my rockwork together in my saltwater tank and used about a tube an a half. I had about 120 pounds of rock that I wanted to form into a few structures in my 75 gallon tank and this stuff worked beautifully! I had been letting my rock cure in large tubs with a circulation pump for a few weeks, so they were still very wet when I used this epoxy to hold them together and it still became rock hard and my structure is SO sturdy. I created a large archway and a complete hollow circle through the rocks. Neither of these are very sturdy structure alone, but with the epoxy I could grab the center of the archway and pick it up with no breaking and no worries. I would absolutely use this product again if I ever need to do another aquascape. It dries stark white, but will soon enough be covered by beautiful coralline algae, so no worries. A few notes: -This is NOT glue. It is NOT sticky. It will NOT "hold" two pieces of rock together. You cannot simply plop a piece of this epoxy on the bottom rock and shove your other rock on top and expect it to hold. It will NOT hold. I found the best way to ensure a sound structure was to position the two pieces of rock exactly how I wanted them and then completely encircle the seam of the two pieces with this epoxy being sure to shove as much as possible into nooks and crannies on each piece of rock as I went around and then smoothing the epoxy a bit up the side of each piece of rock. It works the best if the two pieces of rock can already stay balanced on top of each other without moving without the epoxy. Otherwise you'll just have to hold them until the epoxy begins to harden. -Keep a cup of water close by while you work. As you are mixing the epoxy, dip a finger or two in the water and continue working it. The little bit of water helps it mix much easier and faster and allows it to soften up just a bit so you can get more into the nooks and crannies of each rock. When you get the epoxy mixed and are ready to place it around your rock, dip a finger or two back in the water. Use these fingers to work with the epoxy on the rock. This helps the epoxy stick to the rock and not your fingers and allows you to smooth it out around the rock pieces and into the nooks and crannies. -Let the epoxy harden a couple of days before moving the rock or submerging it in water. I let mine cure about 35ish hours before doing anything with it. I did want my rocks to stay moist, so I poured a bit of saltwater over them periodically and this did not seem to mess up the epoxy at all, but I would be cautious about completely submerging it too soon. I know this was long, but I wanted yall to have an honest review and a few helpful tips! I hope it helped yall out!

I use this to secure my dry rock together when creating a reef aquascape and also for attaching frags. When attaching frags to live rock, you must add superglue gel to both the epoxy side and the live rock side of the epoxy. You basically sandwich the epoxy between superglue gel or it's not going to adhere correctly. It's aggravating at first but if you continue to attach your frags this way you will get better at it. I find when the epoxy is used in water never gets totally hard but stays somewhat gummy. However when used on dry rock and allowed to cure for 24 hours it becomes rock hard. I had to remove a rock from another after 24 hours and it took me beating the rock with a hammer to get the cured epoxy to break. I've also let balls of just epoxy dry accidentally and they next days they are basically rocks themselves. Tips for aquascaping with dry rock: use the little broken pieces from the rock to stick into the epoxy joints you make to help hide the epoxy. Do this under 10 min or so or it will be too hard by then. On rocks that just aren't stable enough and want to roll, you can add little "feet" that stabilize the rock, to keep the "feet" from sticking to the surface they are sitting on, just apply some of the rock dust particles that fall off the dry rock. I've never tried one of the other brands of reef epoxy as this one is cheap ( on Amazon anyway never in any of my local stores) and I've had good luck with it. The only negative is the color, it dries totally white. Which is fine if you are aquascaping with white dry rock but it does show badly on live rock under frags. In the attached pic, most all of the rock is epoxied together, some of these rocks weigh several pounds and didn't balance very well, where the where natural holes in the rock (back side) I did use some zip ties to also help stabilize the rock. Update 9/11/2018- Was almost out so I ordered more and it appeared I would be receiving the new coralline purple color, product came and it was the green dries to white version, so not really happy I wasn't sent the pictured product. Update 3/6/2019- Still using this product, I've used numerous tubes since beginning the hobby and will continue to do so, as this stuff holds up well and is inexpensive. Update 8/18/2020- I still use the same exact method of attaching frags and have not had any issues with my reef aquascape coming apart. If anything, I have difficulty getting frags off, if I decide to move something later.

Turns solid as stone when used as directed. Mixing together takes patience and it does smell quite terrible but this stuff works really well for bonding and sealing. Safe for invertebrates when cured(used some to seal sharp decorations in a jumping spider enclosure once).

I would have given this epoxy 5 stars but there was a big problem, it's not the purple color advertised. I purchased this to do some aquascaping on my dry base rock and the stuff works great. Once dried, I couldn't break the two rocks apart. Some tips to make joining rocks a little easier. Only rip off the amount you need. Don't try to mix a huge portion as this starts to dry quickly If you're working with dry rock, make sure they're clean and dust free as possible knead the putty with your fingers, keep a small cup of water handy. It will start sticking to your fingers. If you keep your fingers damp, it won't stick and will make the putty mix easier Mix the putty until it's all the same color Apply it to your rocks and make sure you spread it evenly on both rocks to make a solid joint You can take smaller pieces of rock or even rock dust and sprinkle it on the outside of the putty to help hide the "seams" Let the rocks sit for a few hours, I let them site for almost 12 hours and they were solid. When I was mixing the putty I noticed it was not purple after I had already started applying it but assumed (yes, I know what happens when you assume) it would change color when it was completely hard, well I was wrong. If you need a strong epoxy/putty to join rocks that's easy to work with and doesn't cost a fortune, this is the product for you. If you're expecting the purple color, look at another product. Update - I see they changed the product description to remove the purple color and are now showing the correct product. I added the 5th star since it is a strong and easy epoxy to work with.

A review said to get the epoxy into every nook and cranny. I glued two flat areas of driftwood together like a butt joint. The pieces kept sagging as the irregular shape prevented clamping. I pulled them apart and scraped away the goop. I drilled small holes into each flat spot. A knife forced the epoxy into the holes and coated the flat area. The knife was a sculpting tool to force the epoxy into every hidden crevice. As the epoxy set the two pieces stayed together. After 24 hours the bond was strong enough for aquarium use. I resealed the unused stick of epoxy tightly in plastic food wrap, so it will not dry out.

Does its job but will make your skimmer go crazy for days. You need to run carbon to get whatever residue it leaves in the water out. Doesn't seem to hurt anything though.

Holds great on rough textures. Does not hold permanently to smooth textured rocks, but thats yo be expected. Worked long enough for my drift wood to get water logged though.

This 100% DOES NOT work if the rock is even slightly damp. Well, live rock and coral tends to be damp. Though specifically stating on the package it works for live rock and corals and has no mention of surface having to be dry to adhere. It does NOT wash off with soap and water and now my hands smell like hair dye/bleach from the strong chemicals. With the minimal purchase of 2 tubes...it makes this an absolutely waste. There are tiny pieces in the holes of my live rock (where the I attempted to attach them) that will not come out and are not drying. With the intense chemical smell, I am not feeling confident about putting that rock back in my reef. My $12 purchase just cost me 10x that in rock of which is not even attached to each other. Infuriating!!