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Apr 27, 2019




Tank Specs:
200G + Sump
UV filter
Custom plexiglass to fit all holes, completely octo proofed.

Water testing from today:
Ammonia 0
Nitrite 0
Nitrate <10
Calcium 380
Alk/kh 9
Phosphate <.2
Salinity 1.021

Temp right now is 78°F, however, if I am approved give me a few days before shipping to get my chiller up and going to get the water to the low 70s.

Current and only tankmates would be live rock, blue legged hermits, 1 serpent star and 2 pencil urchins.

I maintain tank on a daily basis but also have tank maintenance once per week to keep tank pristine as it is in my office.

The current octo inhabitant (Octo) will be moved to a new home. My tank maintenance guy has multiple tanks at his house and has been looking for an Octo after taking care of my tank. He has already happily accepted his new pal should I be awarded the opportunity for a Bimac. I normally would never do this, but considering the Octo is at my office it makes sense to get a diurnal octopus when given the opportunity. My employees wait daily for a glimpse and to try and interact. This would be amazing for everyone and the octo as he would get a ton of attention (and a lot of entertainment for all, even the octo!)

As stated, I would 100% start a journal and post a weekly entry.

PM me for direct contact. The email used for PayPal is an old email that gets too much junk. I'll get you my good email address.

Thanks again!
Apr 27, 2019
Bimac arrived! Hes beautiful! And big! (Even though I got small!)

I have photos and videos from today which I will post as soon as my son (2 yes old) names the octo! I dont want to start a thread before having his name haha. Once I have that I'll start one and post!
Sep 25, 2006
I love that someone is keeping a bimac. I kept bimacs for years, and I hope you don't mind if I provide some constructive criticism about your setup. First, great job providing such a large tank, that's great.
I think a full grown bimac would have no problem escaping with that lid setup. They get bored, and will try hard to find a way out, and I think that top has two major problems:
1) Acrylic tends to bow/curl over time (I think it soaks up water on the tank side, but not the dry side) and that bowing creates gaps and spots where the weight is low.
2) The smart bimac will try everything, and eventually try sliding the lid horizontally , which doesn't take much force. That will leave part of the hole in the top uncovered, and he's out.

To solve both problems I would recommend getting 1" wide 1/4" thick (or thicker) strips of acrylic and "welding" them (glue them with acrylic solvent/adhesive) onto the underside of the covers. Glue the 1/4" edge to the cover so that you make a 1" tall wall that drops down just inside the perimeter of the hole in the top of the tank. If the hole in the tank top has rounded corners, just make the strips go along the straight part of the hole, not the curved corner. Those 1" tall walls will hang down into the hole in the tank top and keep the top from sliding horizontally. They will also help keep the covers from bowing.

I have never trusted the lid-with-a-rock-on-top design, because it's hard to know how much weight is enough, and because eventually I would forget to put the rock back in place correctly. I'm more absent minded than most people, so that might not be a problem for some, but I built a top with a hinge and latch system that would latch whenever the lid was closed. The lid design I used is not easy for most people to build, and is probably overkill, but might give you some ideas. Here's the link to it.
Sep 25, 2006
And about the temperature...
Opinions vary, but I think "low 70s" is probalby iffy for a bimac. In the wild, the average monthly temperature varies between a low of 57 in the winter and a high of 68 in the summer. I always kept mine between 55 and 65. I routinely got more than two years of life out of a bimac when I kept it at 55-58 degrees F, and fed it sparingly. I designed and built my tank like a thermos with a double paned window in front because of insanely expensive electricity in California, so I could pull off the really low temps. From what I've read, even keeping it at "room temperature" (72?) is iffy. As I remember from the reading, they don't hate it, or get sick, they just go through their life cycle at a faster rate, and are done in about a year. Maybe just keep the thermostat in that room set to 72 degrees 24/7, don't let it get too hot on weekends or whatever, and let your chiller compensate for your pump heat, and a a few degrees of room temp. (and don't use hot lights)
If you are very handy/crafty, and want to insulate your tank so you can drop the temp more without getting condensation on the glass, and running a big chiller constantly, the good news is that a cylindrical tank is the easiest to insulate. Let me know if you want specifics about how to do it (it's probably a lot easier to just get a new bimac every year, if the supply holds out)
Another reason I went with the low temperature is that I got all of my animals/tankmates from the local ocean, and I wanted to duplicate the environment so that all of them could live. Many local species are not as forgiving of high temps as a bimac. That's probably not an issue for you.

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