Advice needed for small crack in acrylic sump.

Sablah · May 22, 2020

I bought a used aquarium a couple weeks ago that was setup and running. The previous owner had blue painters tape indicating where the waterline should be. I removed the tape yesterday, and it was conveniently covering up two small cracks in the acrylic. I can feel them on the outside but I can't feel them on the inside. They don't leak, but then again I try to keep the water level just below the cracks, and usually isn't above it very much. It looks like they go almost all the way through the acrylic, but its hard to tell.

I've read conflicting information on various forums, from using weld-on #4 or #16, putting a new piece of acrylic over it, not fixing it at all if its not cracked all the way through, and some said that since its wet it can't be fixed unless the sump is taken out and left to dry for a long period of time, so I'm not sure which course of action I should take.

Copingwithpods · May 22, 2020

Are they cracks or did the previous owner "etch" the water line marker?

Sablah · May 22, 2020

Copingwithpods said:
Are they cracks or did the previous owner "etch" the water line marker?

It looks deeper and more of a "clean" crack than if someone tried to etch it. I asked the previous owner and he said he didn't remember it being there. I thought I may have cracked it when moving it, but I checked pictures I took of how he had everything plumbed (I purchased his whole tank setup) and I can see in a picture that it was there before we took everything down and moved it.

joe2 · May 22, 2020

its super easy to use one of the weld on products...use the thicker gel stuff and just put the weld on onto a scrap of acrylic and then hold it onto the cracked sump and its stronger than new. I would drain the sump first though as acrylic is pervious to solvents and I am not 100% sure that no chemicals will migrate through the sump wall. in 24 hours add the water back. It won't hurt to run your display tank with just a circulation pump for that long. NOTE...do NOT clean these acrylic parts with alcohol for this operation....never let alcohol touch an acrylic aquarium...search youtube and you will see why. Use vinegar or the like.

bsr2430 · May 23, 2020

Thank god it’s the sump!!!! That’s a lot less water pressure on the glass. I’d simply fix it and use it, tank would be another story...

Did you contact the old seller and question him about this? I mean, this is just rude...

Sablah · May 26, 2020

bsr2430 said:
Thank god it’s the sump!!!! That’s a lot less water pressure on the glass. I’d simply fix it and use it, tank would be another story...

Did you contact the old seller and question him about this? I mean, this is just rude...

Yeah, he somehow doesn't remember it was there. I'm not going to try and raise it as a big issue because nothing positive will come from it. It is what it is, sold as-is, and I'd rather be on friendly terms with him so that I can still ask him questions that may come up in the near future than accuse him of anything.

Sablah · May 26, 2020

joe2 said:
its super easy to use one of the weld on products...use the thicker gel stuff and just put the weld on onto a scrap of acrylic and then hold it onto the cracked sump and its stronger than new. I would drain the sump first though as acrylic is pervious to solvents and I am not 100% sure that no chemicals will migrate through the sump wall. in 24 hours add the water back. It won't hurt to run your display tank with just a circulation pump for that long. NOTE...do NOT clean these acrylic parts with alcohol for this operation....never let alcohol touch an acrylic aquarium...search youtube and you will see why. Use vinegar or the like.

Alrighty, thanks!