sealing a bulkhead, no sump necessary. & Fig. 8 puffer stkg./sel.   12/6/11
Dear Crew,
Greetings and happy holidays!  I've been searching the site for the last couple of hours, but couldn't find anything related to my particular query.
 I have a 40 gallon breeder that I had planned to use as a reef tank, but am now looking at doing brackish or planted setup instead.  The tank is drilled in the bottom panel, in the rear-left corner, but I don't really need to utilize a sump as I'm planning on two Hagen AquaClear's for filtration.  It's been water tested over the last few days using only a ball valve to stop it from draining, but I was looking for more of a long term solution to sealing this unnecessary hole.  Any thoughts?
<Can you not simply seal off this/any drainage holes in the tank, e.g., with small bits of glass and aquarium-grade silicone? Silicone is nice because you can cut it away if needs be, freeing up the holes should you need them down the road.>
Also, in looking into the brackish system, I have developed an interest in Figure 8 puffers, but have read conflicting information re temperament, compatibility, and minimum tank sizes.  If keeping these and bumble bee gobies, how many would be recommended without overloading my tank and causing aggression issues.
<Figure-8s are generally easy to keep. As a base-line stocking density, allow 20 gallons for the first specimen, then another 10 gallons per additional specimen. With good water quality you might be able to keep one or two more. A low salinity is fine, so plants are an option, e.g., SG 1.002-1.003, with appropriate salt-tolerant plants like Vallisneria, hardy Crypts, some of the Crinum species, and so on. They do work well with Bumblebees, but these gobies are fussy feeders, so research that aspect carefully. Figure-8s are territorial but not especially aggressive. They are fin-nippers though, so cannot really be recommended for community tanks. That said, some folks have kept them with pushy, fast-moving tankmates like Orange Chromides, Monos and Scats.>
Thanks for all of the resources you provide,
Dustin
<You're welcome, Neale.>
Re: sealing a bulkhead, no sump necessary.  12/6/11
Thanks for the quick response, Neale!  And yes, I can get some glass and seal up the hole that way. Would you recommend using a piece inside, outside, or both?
Cheers,
Dustin
<Inside would be the ideal, I imagine, so the water pressure forces the two bits of glass together. Do test carefully outside before bringing the tank indoors. Do read and follow links:
http://www.wetwebmedia.com/aqrepairfaqs.htm