Acrylic tank into sump


New member
I have a 130g acrylic tank 60x20x25.....I was thinking of using it for a sump/fuge for either a 180g or 220g......The tank is made from 1/2 acrylic and braced around the top....What is the max height I could cut the tank down without having to replace the bracing? I was thinking somewhere around 16-18 inches.

any help appreciated?


New member
I'm sure ACRYLICS will chime in soon. I'm pretty sure it will be less than 16". If you cut the top off carefully you could flip it and reweld it to the top of the tank again.


New member
To know for sure, you can ask ACRYLICS on this DIY site. Look for ( Acrylic questions?? I can help here) pull up the last page and make a post. He has alway responded to my Qs very quickly.
Dealing with that much water you need to know FOR SURE. Not just I think you'll be alright.


New member
As mentioned above, ACRYLICS will have a definitive and foolproof answer. What I have in my acrylic sumps is something akin to a eurobrace but is really an interior "ledge". Its a couple of inches below the rim on the inside of the tank. I think this adds a good deal of rigidity but also prevents a great deal of salt creep from leaving the sump.

My hunch is that regardless of the reduction in height, you will most assuredly see bowing on the 60" side... where there is bowing there is risk. my.02


RC Sponsor
Premium Member
My guess is that if you remove the top and cut it down, you will get some deflection even with the 1/2" acrylic. I would strongly suggest adding some bracing to keep it from bowing. I have two 18" tall sumps under my tank. They too are made of 1/2" acrylic and are both about 90G each as measured. I keep the water level in them at 12" of depth. They both bowed out a bit which was something I wasn't expecting when I designed them. In hindsite, I should have added some bracking along the top edges.


Active member
The others have it correct IMO.. While many do cut their tanks down and leave them rimless, it's not something that is wise - esp in the long term. But go ahead if you wish, cut it down, add your baffles, just leave room for some bracing. Water test it for a coupla weeks, when you see the deflection - you'll know you need the bracing. Orrr save yourself the time and just add it now :)

Rimless tanks put a good bit of strain on acrylic, esp in the corners - that's why rimless acrylic tanks always seem way overbuilt.. they kinda need to be. And 1/2" material for a rimless tank that size is nowhere near what you need :)



Premium Member
Trust the expert! I had a custom sump built, rimless, the shop swore it would be absolutely ok. It was several years before I got off my duff and set up the tank.... several months later just I am ready to go to work... where is this water coming from? Son has to run over, drain the sump, drain the tank below the overflow, find another tank to use for sump etc. I was lucky the seam didn't split all the way it just oozed down. The rim is a pain, but I will never do again ( people told me to add, eh I hated). Now I'm afraid to trust the sump at all. very very expensive oops on my part :(.