Cody;174982 said:
Alright so I have a question... my tank came with a plumbing kit... 1 & 1/4" drain and 1" return.. I don't know exactly how to plumb the water to and from and how to put the bulkheads onto the tank... (I know you have to use the rubber pieces) But if anyone could help that would be greatly appreciated! Also, not sure what size tubing to use to transport the water........ :/ More pictures coming soon.
The bulkheads will either have male barbed fittings for vinyl hoses, or female pvc slip fittings. The pvc pipe or vinyl tubing should be 1" of 1 1/4" (inside diameter) to match the bulkheads. If you use pvc pipe, use pvc pipe glue. You can also order fittings that convert pvc to barb fittings, so you can run pvc pipe for part of the way, and then vinyl hose for where you need flexibility.
For the bulkheads you need one rubber seal for each bulkhead, and it needs to be sandwiched between the glass on the inside of your tank, and the flat flange on the part of the bulkhead with the threaded tube (shaft) on it. Slide the rubber ring over the threaded shaft, then from the inside of the tank, push the threaded shaft through the hole in the glass. Then put the nut part of the bulkhead onto the end of the threaded shaft that is sticking out of the hole, on the outside of the tank. Tighten the nut down with your hands (and maybe a gentle final nudge with a wrench, but not too tight or the plastic might break).
I use bioballs in a wet/dry filter on my 60 gallon bimac tank. As a rule of thumb, I think you will need to have a volume of bioballs that is equal to about 10% - 15% of your tank volume for a tank fully stocked with fish. That would mean 9 - 13.5 gallons of bioballs for a fully stocked 90 gallon tank. If your octopus, and tankmates constitute a bioload that is less than a full compliment of fish, then you can reduce that accordingly, but I'd say you'll need at least 5 gallons of bio balls. I feed my cold water bimac tank very heavily (lots of filter feeders) and I get by fine on 9 gallons of bio-balls in a 60 gallon tank with a fully grown bimac). It looks to me like one of those drawers can only hold between one and two gallons (231 cubic inches in a gallon), so you might need to rethink your filtration. I also found that if I only had a small crack to let fresh air into my bioball chamber, that I got low PH due to insufficient gas exchange. An opening of about 12 sq in on top has been sufficient. You might need to cut air holes in the top edges of the bioball drawer(s) if you find that your gas exchange is not good enough. Good gas exchange is especially important for an octopus. You'll need a way to spread the water out and sprinkle it evenly over all the bioballs, so that all of their surface area is always wet. I use a flat acrylic tray with lots of holes drilled in the bottom.
Note: I don't use any live rock, so my bio balls need to do all my filtration. If you will be using live rock, you can get away with less than 5 gallons of bioballs (or none at all). If you don't use live rock, you'll need another way to keep nitrate from building up, like a Remote Deep Sand Bed (RDSB), a nitrate filter, or lots of water changes.