Patched Up bottom of the tank - Silicon

[LiveRockRob]

Hi,

I purchased this 80 Gal acrylic aquarium and there are 3 patched up holes in it.

Here are the pics:


One of the patch jobs (http://reefcentral.com/gallery/showphoto.php?photo=271562)

View of the entire tank (http://reefcentral.com/gallery/showphoto.php?photo=271563)

It looks like the aquarium was previously used with a sump or other equipment that would utilize the holes for filtration. The previous person that had this aquarium setup used it for freshwater cichlid tank. and did not utilize the holes.

I saw the tank in action, and it didn't leak, but it looks like the silicon is coming off. I'm not sure how to tell if this it REEF SAFE silicon either.

Any advice? or a way to fix this?

Thanks

Robert

[VacavilleFC3S]

is that just an acrylic rectangle siliconed over the bulkhead hole?

[theredben]

First of all, if this is Acrylic then you should not need silicone, scrape that stuff off, get some small peices of acrylic and weld them on with "Weld-On" 3 or 4. Silicone does not bond well with acrylic.

Have you considered using those holes for a closed loop?

[aquamanSD]

They look like returns that were patched up that someone didn't want. I'd definitely use them as returns again. I have 6 in my tank and they work so much better. You want good flow on the bottom :)

[LiveRockRob]

Hi,

Thank you for the advice.

I have never heard of "Closed Loop" system. Could somone explain it to me, and possibly direct me to a site that would have some images and detailed info on what "Closed Loop" system is and how to construct one. Thanks

aquamanSD, would you have some photos of yours? Maybe I can see how your is constructed.

Also, in order to utilize the holes, what aditional equipment is needed? Is this system based on a sump, or refugium?

Thanks again for the responses.

Robert

[der_wille_zur_macht]

Do *not* use holes in the bottom of your tank to return water from a sump. If the sump pump fails or you turn it off, the entire tank will drain. Some people try to use check valves to combat this, but they're extremely failure-prone. A bit of sand or a shred of algae can clog one to the point where it stops working.

That said, using holes in the bottom of the tank for a closed loop is perfectly acceptable. Do some searching on here or in the DIY forum if you're not familiar with closed loops. Basically, it's a way to use an external pump to add water movement to your tank. You need a pump, and plumbing form the tank to that pump's intake, then plumbing from the pump's exhaust back to the tank. This plumbing can simply go over the back wall of the tank (as is typical for a canister filter) or through bulkheads in the sides/back/bottom of the tank.

As others have said, if you choose not to use those holes for plumbing, seal them off more thoroughly. Silicone is a horrible adhesive for acrylic, it's simply doesn't hold well and it's certainly not something I would trust. Even if it was working OK for the previous owner, draining and moving the tank could have strained it enough to break the seal. Use "real" acrylic adhesives to accomplish this job - again, searching in the DIY forum will be a big help if you're not familiar with the correct methods.

[aquamanSD]

I cant find my pics i took of it before. :( And mine DOES come from my sump cause i don't like closed loop systems cause of the spot it has to suck water from... I'd rather use some tunze streamers or something for additional circulation. der_wille_zur_macht makes a very good point... I do have a high dollar clear check valve that does the job very well (so far) and i do have shut offs all over in case it does fail but i do have to be home to manually shut one it the check valve were to fail. Also its highly unlikely that any big pieces of anything could go thru the returns the way i have the sump set up.
I'll look some more for the pic or try and take another one. Im not much of a picture person. You can still make it a closed loop just fine.. Just need a few bulkheads, ball valves and a pump and some pvc or tubing to connect them together and set the flow. I used the bendable ball socket tubing in the tank then and drill a hole in the live rock where i want it and slide it over it so its basically hidden.