[doHTML]<br><center><h1>'The Longest Night'</h1>written by: Benjamin Volk</center><br>
<img src="http://www.generalaquaria.com/articles/plenum.png" style="float:left">
<br><br> There comes a time in every aquarist’s life that they have to do something they really don’t want to do (such as writing this entire article a second time tonight due to a computer hardware failure). Such was the situation I found myself in Sunday night with my 29 gallon saltwater tank. Having set up the tank over two years ago, I did not think at that time, that I would ever need a plenum. I thought to myself, who needs a plenum when I’m only going to house at most, three1 to 1½ inch long fish in a 29g tank, and if I don’t put in a plenum, I can start it cycling today instead of 3 days from now. Patience would have proved quite virtuous at several points in my fish keeping experience. That doesn’t help me now though. Now I’ve been bitten by the VARIETY bug. Two fish in a 29g tank just isn’t going to cut it for me anymore. I, like many amateur hobbyists want to cram as many different fish into my tank as I can possibly stuff into an empty sardine can. However, unlike many novices that get bitten by this bug early in their hobby lives, I know what can happen with the cycle, etc. That’s why I’m adding a plenum now. Adding a plenum to an already successful tank will let me cram an extra 2 to 3 one-inch fish in the tank, or maybe even 1 two-inch fish without disrupting my here-to-for great water quality. Only there’s one problem; adding a plenum to an existing tank is no easy task.
<br><br> My mind was made up weeks ago however. All the articles and books I’ve read tell me that a plenum is the way to go for some cheap water quality conditioning. So I went to the hardware store where I was able to purchase everything I needed to make the plenum, which included:
<br><br> 1. A 36-inch section of ¾ inch PVC pipe cut into several 1 to 2 inch pieces.
<br> 2. One sheet of egg crate (the plastic type used in florescent light fixtures).
<br> 3. Enough vinyl or fiberglass window screening material to cover the inside dimensions of the tank 3 times over.
<br> 4. (optional) A tube of GE silicone II caulk (or other aquarium-safe glue), to attach the PVC pipe pieces to the bottom of the egg crate.
<br><br> Having bought the required hardware, I promptly began preparing it as soon as I got home. First I cut the egg crate so that when centered against the back glass, there was a 1½ inch gap on each of the other three sides. Then I cut and glued the PVC pipe pieces onto the bottom of the egg crate using the silicone caulk. I didn’t pre-cut the three sheets of window screening to fit on the bottom of the tank; a decision that would come back to haunt me as it ate up precious time with the fish in a stressful environment.
<br><br> I was almost ready to start at 9pm Sunday evening. I just had a few more things to get ready. You see, installing a plenum in a new aquarium is simple and easy. Installing a plenum in an existing aquarium takes a good deal of planning and work to pull everything out of the aquarium, store it while it’s out, and then put it all back in, in reverse order. So I thoroughly cleaned out a 39gal. plastic trash bin to siphon the water into and scoop it back out of. So far so good, except that had I done this before, I would have known to get a caster wheel base for the trash bin so that I could easily wheel it out of the way once it was full.
<br><br> After gathering a few more buckets and all of my supplies, I began siphoning the water out of the tank into the trash bin. Once the water level had dropped to the point where the live rocks were beginning to stick out of the water, I carefully moved them out of the tank, into the trash bin. While doing this, I was gently brushing off any marine life that was still clinging to the rocks, so as to avoid crushing them in the shifting of the rocks. So far, it was smooth sailing.
<br><br> I continued to drain the tank until there was only about 2 inches of water above the substrate (remember, none of my fish are very big, and 2 inches of water is more than enough to cover them 2x over). At that point I had to move all the life out of the tank. Now here’s where I started to go wrong. Instead of moving it all into the trash bin like I should have, I put everything in a 5 gallon bucket, with no filtration or aeration or heating. This would prove to be a near fatal mistake as the project that I thought I could complete within an hour, took more than 6 hours before I could add the fish back to the tank.
<br><br> I then scooped out the substrate into yet another bucket and realized upon doing so, that I had so much substrate in there, that I was going to have to sift through half of it to separate out the marine life and move it to the half that would be on the top layer of substrate when the project was finished. An hour and a half later I had hand-sifted through approximately half of the substrate and cleared it of all snails and hermit crabs.
<br><br> Finally I could get on with the project, I thought. But wait, this was the perfect opportunity to scrub all the tough coralline algae off the glass, as well as the salt deposits off the outside of the back glass (in the two years I’ve had this tank, I never once cleaned the back glass until now. The salt deposits had grown to nearly a centimeter thick). So I cleaned the tank, and then I took a few more minutes to do some maintenance work on the aquarium stand. One of the center braces had broken free, so I secured it with some counter-positioned L-brackets to make sure it wouldn’t ever break free again. Then I cleaned and set up the stand again.
<br><br> At this point I looked at the time, only to discover that it was already midnight. I was three hours into a project that I thought would only take 2 hours, and I had barely scratched the surface. Had I been smarter, I would have moved my fish to the trash bin at this point, instead of just trying to pick up the pace. Unfortunately, this is not the first time my fish have had to suffer for my stupidity. I can only vow, never again to make the same mistakes.
<br><br> It was time to get on with the project. I placed the base of the plenum in the back center of the tank, and then cut two sheets just big enough to cover the bottom out of the window screen. I then rinsed and sifted through a strainer, some aragonite sand that I had planned on using as the base layer. This too, I should have done before I ever started. Once the sand was in, and covering the plenum with about a centimeter of sand, I covered that with the two-inch thick layer of crushed aragonite that I had picked free of critters earlier.
<br><br> At this point, I cut a third layer of window screen and laid it down. This third layer does a couple of things. First, it makes for a sturdy foundation for live-rock posts (we’ll get into that in a future article). Second, it keeps substrate burrowing creatures from burrowing into the anarobically active layers of substrate, which can disturb their cycle. Finally, it allows you to stir or vacuum the top layer of substrate without disturbing the plenum.
<br><br> After covering the third layer of window screening with the remaining substrate, I quickly filled the tank with a good 2 inches of water above the substrate layers. I rearranged the live rock I already had (this was not custom made live rock, so I made sure to arrange it in a manner in which the largest surface area of substrate would be exposed). I refilled the rest of the tank with the water from the trash bin, and re-arranged all of the power heads, heaters, and other filters. Now I could move the trash bin out of the way, which let me work much faster.
<br><br> It was time to re-add the fish. But no sooner did I walk over to the fish bucket, than I realized what a fool I had been. A quick glance at the clock showed 6am. The fish had been in a 5 gallon bucket for nearly 7 hours with no heating, no aeration, and no filtration. This was NOT going to be good.
<br><br> The first fish back into the tank was my yellowtail damsel, Clyde. He was so pale that the only bit of color left on him was a little blue patch on his belly. He was so sluggish that I easily scooped him up by cupping my hands into a bowl, which seemed gentler than netting them back out. He was still alive, but just barely.
<br><br> The next fish back into the tank was my clownfish, Bonny (it and the yellowtail damsel hang out together and like to bully other fish, hence I named them Bonny & Clyde). Other than swimming a little slower than normal, and being slightly less colorful, Bonny looked and acted normal, until she was dumped back into the tank. Once back, she drifted immediately to the bottom front of the tank and seemed to be resting on the substrate. I thought it was all over for sure.
<br><br> Finally, out came the newcomer, I haven’t yet named. He was a beautiful blue velvet damsel that fluoresced brighter than most neon tetras do. On the first day he was added to the tank, he sustained a large fin-nip in an act of hazing by Clyde; but then held his own in the tank for the next two days. Until he was pinned in a small bucket with no-where to go that is. I suspect that as the fish were running out of oxygen, Bonny and Clyde thought up a survival strategy of killing off the extras that were using up their oxygen. The blue velvet wasn’t quite dead, but he has nothing but one thin string for a tail fin, and badly gashed dorsal and pectoral fins. I fully expected him to die within the nest 36 hours.
<br><br> Then came all the extra critters, the pencil urchin, the emerald mythrax crab, the nassarius snails, the cerith snails, the astrea snails, and all the baby blue legged hermit crabs you could shake a stick at. They were all just fine and showed no signs of stress that I could determine. When I looked back down at the bucket, I saw one final guest I hadn’t expected. An unknown crab that can only be described as a miniature rock crab; he measured about the size of a dime and looked just like a rock crab. So I picked him up and took a closer look at him. As I did he raised his claws at me as if to say, yeah, so what, you wanna fight about it? I didn’t, so I dumped him in the tank and watched him scurry away to likely never be seen again for the next 2 years.
<br><br> I added an extra gallon of fresh water to top off the tank to account for what little water was lost during the whole ordeal, then added about 3 full cups of salt. This would seem like overkill on the salt, but I could tell the tank had been running a little lean on salt the past month or so. Even though my hydrometer said it was already .03 over, I knew from borrowing a friend’s refractometer that my hydrometer read .03 higher than it actually was anyway. So I added the salt and watched to my amazement as Bonny and Clyde regained their color and perked up within minutes. Clyde even picked up more color than he had before. Even my Blue Velvet Damsel seemed to perk up.
<br><br> It’s now 72 hours later, and I’m pleased to say that even though I made some major mistakes, I didn’t suffer a single casualty (with the exception of one astrea snail that I thought was dead and just a shell, and didn’t bother to return to the tank. I returned it 12 hours later, but now it really is dead and just a shell. Oh well, food for the hermit crabs is what I say. The other 10 astrea snails will reproduce enough to replace that one anyway. I did add 2 additional fish in the meantime, one scooter blenny which is one I wanted to add in the first place, and another type of damselfish that I primarily got just to take the pressure off of the blue velvet damsel. It’s now the only one being picked on, but it’s considerably bigger and doesn’t even seem to care. It has yet to get a fin nipped; I think Bonny and Clyde, although willing to play chicken with him, are two scared to nip this big boy. In the meantime they are ignoring the blue velvet, which will hopefully give him a good opportunity to heal while still remaining in the environment to stake a claim to some rock or cave of his own.
<br><br> I will have to keep an eye on my water quality over the next few weeks, if I see a large spike; I will have to remove one of the fish (probably the new big fish on the block). I won’t worry about anything up to 3 ppm of ammonia, but if it surges beyond that, I’ll definitely cut back, maybe move one of them over to one of the QT (Quarantine) tanks for a few weeks.
<br><br> Last Sunday night was the longest night of my fish’s lives, to say nothing of my own exhaustion. Was it worth it? I think so; but then, what do I know? I’m just a variety crazed aquarium enthusiast.
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