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Tank Setup - I Need Some Advice


Mar 9, 2009
Some of you may know me from this thread in which many of you made it clear that I could not take shortcuts. Well, I listened. Today I bought an RO unit.

Anyway, here is where I stand, and I need some advice on what I should ultimately do.

The tank is 46 bow front aquarium with 60 pounds of live rock. It was filled with NON RO water and is on the last leg of the cycle. I talked to my LFS (Wet Pets near Pittsburgh PA) and they are ordering me a briareus - timing such that it will be here in about a month.

Ultimately, I would like the vast majority of the water in the tank to be RO water.


Keep it in the 46 gallon bow front and just do water changes with RO water.


Fill up the new 55 gallon tank I have lying around with RO water and transfer the live rock to that tank.

I am also concerned that after adding the live rock, there isn't much space for the octo to move. Should I take some of it out? Stack it higher?

Whether it is in the 55 or the 46, there isn't going to be much room on the ground unless I drastically reduce the amound of live rock in the tank... in which case, I could do a fish + live rock tank in the other.

How much live rock should you put in an octopus tank? I keep reading 1 LB - 1.5 LBS per gallon.

Another concern is that it is going to be hard to octoproof the front top of the bow front. On the 55 I could buy plexiglass that will fit the top perfectly then drill holes or use mesh to make sure the skimmer and filter fit.

What do you think?

current equipment:
octopus bh-100f skimmer
aquaclear 70 gallon filter
aquaclear powerhead (for 30 gallon..oh well)


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I assume there is little difference between the length of the 45 and the 55 and that the gallonage difference is in the bow part of the 45. If one is longer, then that would get the vote for a briareus. The additional water volume in the 55 (assuming no sump for either tank) also gets the octo vote.

For either tank, you could add one (two would likely be better) back to front supports (attached under and flush with the lip - aquarium - and only aquarium (inert ingredient is vinegar, non-aquarium silicone containes ammonia that does not quit releasing to the tank for a long time, voice of experience, not hearsay) - silicone will work to set the support) and then cut a piece of plexi to fit, cut it in 2/3, 1/3 left to right and add a full length plastic hinge (the flat flexible kind are very inexpensive and hold up well, a full piano hinge is overkill but will also work as long as it is ALL plastic/acrylic (Tap Plastics has both and they can be ordered on-line). The back third can stay fixed or difficult to remove and can be altered for whatever has to come out of the tank. We did something similar with an acrylic tank (we had to add our own surround lip though - there is a photo in Nancy and Colin's book if you have it handy) and it works very well. We drilled the top using a peg board as a template (well, Neal did and I just listened to him complain about the number of holes :sagrin:) and attached acrylic hasps to lock it down (we also did this with Bel's hex shaped tank). The hinge arrangement works very well for maintenance (you will need a handle.A heat gun, acrylic cement and a strip of left over acrylic make a nice looking handle but a zip tie through two of the vent holes works very well and is not terribly obnoxious). If you opt for screen (a good idea since you have no open sump for heat escape), I would still use a hinged arrangement and use acrylic for the back third (likely no need to drill holes if the front 2/3 is screen but I have not made one this way). Taking the time to make a hinged lid is well worth the effort.

1-2 pounds/gallon of LR sounds right. I try to stack mine so that there is a fairly large empty space behind the LR and then attempt to keep a current running through the back. I am not sure it keeps the unexposed LR more alive but ... "if it ain't broke ...". I fashion as many little caves as I can manage and do stack it higher than what you are showing. Getting it stable is the tricky part. Bel's tank was our first octo tank attempt and I secured the rocks with Gorilla Glue. None of my other octo tanks have been glued though and I have had very little rock rearrangement with the hummelincki. We will see if the briareus changes my confidence though as they seems to do more landscaping.
I took your advice and I'm setting up the 55 for the octo. It'll be a much better setup for the octopus because I'm going to fill it with RO water initially, and I'll use live rock from the 46.

I bought rather large pieces of live rock and stacking them higher worked well enough.

I bought plexiglass, a saw, a drill, and some plastic screws with plastic wingnuts for the top. I already have aquarium grade silicone to attach it to the top, and today I cut out two sections of plexiglass which fit the top exactly. I have another section of plexiglass I'm going to use as the lid, and I am going to use a circular saw to make holes for the skimmer and what will have to be a canister filter. After I silicone bio balls into the skimmer intake and outflow, it is an escape proof design.
Hayek;135856 said:
I bought plexiglass, a saw, a drill, and some plastic screws with plastic wingnuts for the top.

:sagrin:What have I started?!?

You forgot the sandpaper :roll: You will find the plexiglass edges will easily sand. Sanding will not only look neat and professionally constructed but will also keep the swearing out of messing with the top. Unsanded plexiglass is very sharp and 20 min (max) to sand any cut edges makes a huge difference.

You will need a brace to support the length (I recommend setting the brace perpendicular to the length) as the top will sag and heat warp from the temperature difference between the water and the top lighting. If you use left over acrylic for the brace, it is extra important to sand the edges before you mount it.

Sounds like you are actually enjoying taking your time and being a bit creative :wink:
The 55 has a divider in the middle of the top. I cut two pieces of plexiglass - one for each side. They fit perfectly. It is extra thick plexiglass so it doesn't sag or bend at all. I'm going to wait until I make holes for the filter and skimmer before I attach them. I'll post some pictures soon.

Though it has been tough finding non metal parts to secure the tank, it has been a fun project thus far.
You may not want to put the plexi top on the tank until after you drill the holes. Thick or not, the heat difference on the lighted top vs the water side will cause some warping. Mine do fine as long as I keep them latched tightly but if they are left closed and not secured, I get warping even with the air holes (but less than before we drilled them).
Here is what I have so far. I attached it to the top with aquarium grade silicone and used plastic screws. It still needs some sanding.

Oh, and an easy way to stop warping is to go 3-D. Using acrylic cement, glue 1/2" or 3/4" wide strips of acrylic, along all four edges of your acrylic top make a shallow tray out of it). Better yet, move the strips in a couple inches from the edges and gllue them to the bottom (the tank side) of the lid. They'll make the top nice and rigid (like an I-Beam).
I am confused on how the top works. I see a hole in the middle and screws on the sides but can't tell the intent. It does not look like the screws fit into the surround to hold the top in place and I don't understand how the hole in the middle will be covered. Sorry to be a dumb bunny but better to ask and get a clear explanation be for a problem occurs.


I used silicone to stick the screws to the bottom part.

It was the only way I could do it with the materials readily available. I bought everything at Lowe's including tools. (except silicone which is aquarium grade)
Ah! Pictures ARE worth 1,000 words! Other than the maintenance aspect, the lid should easily contain an octopus.

Is the outer support also siliconed to the tank lip? I am assuming so or an octo can just lift it. I believe your design will eliminate any warping concerns without adding a cross piece. You will want a handle of some sort on the removeable piece. Neal made me a nice looking one by bending a piece of scrap on one tank but two holes and a zip tie work very well on some of my others.

You might reconsider on a hinge for the top piece for maintenance (Tap has an acrylic length of very inexpensive hinge that has held up and worked well on one of my tanks (I have also tried the slightly more expensive one but the flat one has held up perfectly and is super simple and can be cut with scissors). Having to align the top every day will be a chore. If you cut your top length wise so that there is just a strip along the back that is screwed in and then add the hinge and some hasp style clips you will save yourself the couple of months worth of grief I went through trying to use nylon screws :hmm:

You will be amazed at how good those rough cuts will look after you sand - AND DO SAND or you will cut yourself frequently enough to use ugly words :roll:

While you are cycling, put the lid fully on the tank and take some temp readings at night and during the day after the lights have been on (you don't need any lights for a ceph so any low temp light for viewing is quite acceptable (no lights are fine as well) as long as you don't try to put something else in there that requires the higher light source. A couple of LED lights or a cheap flourescent attached to the shelf would work nicely I think.) and all equipment is operational. Drilling air holes will help some if you have a lot of heat build up. You may also need a fan between the lights and the top if the air holes don't provide enough cooling.

Looking GOOD!

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