Origami

Thanks for the reply. So how do you know when to change them? My HID lamps are double ended HQI MH, 10,000K, 150W, on 8 hours per day, off 16 hours. CF's are 96W actinics, on 12 hours per day (2 hours before and after the HID). Does that help bracket the question of performance expectation?

It's never to early to plan, is it? What is the generally accepted replacement time for Power Compact and MH lighting? I'm recalling 6 months and 1 year, respectively, but would like the input of others who've done this a time or two. Thanks. Tom

I recently had the same problem when setting up for the first time. I'd hauled many 5-gal buckets of RO water home from work only to find that my TDS was up around 250 ppm. Snooping around, I found that the techs had installed sediment filters only ahead of the RO membrane, resulting in chlorine damage to the membrane. I bought my own RO/DI system from Air, Water and Ice and now I have 0 ppm TDS.

I built up the sump today. I really didn't like the feel of the polyethylene tubing at the end of the caulking gun. However, I did get another suggestion on RC that I tried. If your first run a bead of sealant along the line where you intend to mount your baffle, you can press the baffle against this bead, driving it into position and seal the back edge. The sealant is thick enough that you can then just run beads on the forward edge finishing the job. It works pretty well actually. It helps to mark the outside of the tank with a dry-erase marker to help direct you where to put the beads of sealant and to align the baffle. As for cutting 1/4" plexiglas (which I was worried about), a cheap plywood saw blade mounted on a table saw (or a circular saw) works pretty well, though you will get some melting of the plastic saw dust as you cut. I used a smaller circular saw blade mounted on my 10" table saw and it worked just fine. Also, a plain-old jigsaw with a wood-cutting blade works well for shorter cuts and for notches. I do offer this advice, however: Especially when using a table saw, wear safety glasses and a long-sleeved shirt as there are little bits of hot plastic thrown off the blade while cutting the plexiglas. When it comes to cleanup, cut some scrap wood to help clean out the plastic residue from the saw blade gullets and, after removing the blade, use a razor to knock any plastic buildup off of the blade edge.

I agree with you, Bob. This is the direction I was headed as well but I may give this approach a try just for purity's sake. I bought a couple of feet of polyethylene tubing at Lowe's today just to see how it feels to try to caulk a decent bead in from 10 inches away into a 1-inch inter-baffle gap. If it doesn't feel like it'll be as clean as I'd like it, I'll probably just go with the blocking approach. At least, I know that, with the blocking approach, I can both maintain the baffle spacing easily enough. Tom

Thanks, Dandy. I may just give that a try! The extra rigidity of the ro tubing would certainly make it easier to guide. Maybe this weekend....

Bob, that's exactly what I was thinking of doing - "gluing" (using sealant) small acrylic blocking behind the individual baffles (after the first was installed, that is) and locking the baffle down from the accessible side with a bead of sealant around the perimeter. Antiguan, thanks for the link. I looked at it and that approach makes some sense as well. Looks like he used the aluminum bar as a long putty knife to apply the sealant an inch or so at a time. Either way will work, it seems. I just wanted to see if there was any magic method I was overlooking. Thanks for the input!

I'm putting together my first system and am building a sump from a new glass 20H tank (that's what'll fit in my stand). So anyway, I've got the sump designed and have incorporated a bubble trap into the design as well. I've even gone so far as to mock up the baffles in cardboard to see how it will all fit together. The baffles will be 1/4" acrylic. Here's my question: I'm planning on putting the bubble trap baffles 1-inch apart. However, I've read that I'm supposed to put aquarium sealant on both sides of each baffle. This leaves me wondering exactly how I'm supposed to get the aquarium sealant down into this 1-inch space when there's another baffle next to the one I'm putting in. I'm hopeful that any of you who've been through this before can enlighten me on the technique you used. Right now, I'm thinking about only sealing one side of each baffle and maybe putting an acrylic block on the back side of the baffle to "pin" it in place. It may, however, be sufficient to only caulk one side of the baffle. I don't know. What's your opinion?