AQUATIC HORTICULTURE		BY KAREN RANDALL

KAREN RANDALL

A Project Finally Completed!

Two years ago, our school system was given a large number of aquariums, including a 6-foot 100-gallon tank. While we were thrilled with the donation and able to use most of the smaller tanks, the 6 footer and several 4-foot 110-gallon tanks were simply too big for classroom use.

The 110s were all in like-new condition, so we traded them to a pet store for other equipment we needed. The 6-foot tank was filthy, pretty badly scratched and had multiple holes drilled into it, several with PVC pipe overflows cemented over them for use with a centralized filtration system. It really wasn’t in saleable condition. When I expressed interest in it, the school gave it to me as a “thank you” for the work I have done on the school tank project, “Treasures in Glass Boxes.”

I had always wanted a 6-foot tank! This one even had its own stand, even if it was only made out of 2x4s. There were a couple of other little problems standing in my way, however. First, was the problem of getting the PVC out of the tank and patching all the holes. Second, was the fact that there was already a bank of tanks (a 55 with two 20 highs under it) on the wall where I envisioned putting this tank. Those tanks were fully planted and full of fish.

Do you have questions, want to discuss the issues raised in this column, or read the comments of other aquarists and the answers from columnist Karen Randall? You can do so by going to: Aquatic Horticulture Interactive.

The tank originally sat on the lawn, while I worked on getting it clean. Not only was it dirty, but the water in it had been allowed to slowly evaporate, leaving hardwater deposits all down the sides. By the time I got it clean enough to even want it in the house, my dear (and usually very supportive) husband was really tired of trying to mow around it. It took three strong guys to get it from the lawn onto its stand in our screened-in porch. There it sat, while I chipped away at cement, removed PVC and patched holes.

In the meantime, I was researching lighting. I found that there is no economical way to light a 6-foot tank. I’d been living in the secure, comfortable world of the 4-foot, shoplight-lit tank for too long! While there are 6-foot shoplights and tubes available, the selection of tubes is pretty poor in this length. I was not able to find the tri-phosphor 5000 to 6500 Kelvin (K) tubes I prefer.

I looked into building a custom hood using a combination of 24- and 48-inch tubes, but the cost of that option was fast approaching that of either very high output fluorescent or metal halide lighting. I had always wanted to play with an open-top tank, and here was my opportunity.

In the end, I decided to spring for metal halide pendants with deep reflectors, from Hamilton Technologies. Because the tank would be in our living room, I didn’t want too much light spilling out between the lights and the top of the tank, a problem I have heard about with some of the less-expensive, shallower pendants.

I chose 175-watt 5500 K bulbs for the two fixtures. Many people would choose three metal halide pendants over a 6-foot tank. The recommendations are for one light for every 4 square feet of tank surface. I decided to stick with two rather than three to keep electricity costs down. I felt that the two lamps would give me areas of intense lighting where I could place plants that needed this much light, while the lower light areas of the tank could be planted with plants that do well with a little less lighting.

Now the lighting was under control, but the more I thought about it, the unhappier I became with the idea of that rough 2x4 stand in my living room. My 70-gallon tank is on a plain wrought iron stand in the family room, and I long ago dressed that up with a fabric “skirt” that complements the furniture in the room and hides the equipment underneath. I suppose that would have been an option, but I really wanted something a bit nicer for the living room!

In the end, I bit the bullet and had a carpenter friend use the 2x4 stand as the base frame for a lovely cherry wood cabinet with brass hardware that matches my living room furniture beautifully. (Are you listening for the sound of the cash register? Ka-ching!)

OK, we’ve got the beautiful stand, the expensive lights, the tank... Wait a minute, the tank! Does it make sense to sandwich a beat-up old tank between these $$beautiful$$ accessories? I think you can see where this is going. So, off I went to my favorite aquarium shop to buy a new tank. And while I was at it, a 100-gallon long is an awfully shallow tank. We might as well upgrade to a 125, right?

Nothing in life is ever easy and my tank upgrade was not going to be an exception. It turns out the only company my aquarium shop has access to that currently manufactures a 6-foot tank without braces on top is Oceanic. These are beautifully made tanks, but more than I, even in my new-tank frenzy, was able to spend. Most manufacturers now make even their large tanks from thinner tempered glass. This makes the tanks strong, but lighter and easier to handle and ship. The downside is that the glass can’t support the weight of a 6-foot wall of water without top bracing.

The shop I use buys most of their tanks from All-Glass, but the 6-foot All-Glass tanks come with two support braces, right under where my (already purchased and sitting on the porch) metal halides would hang. We called All-Glass and they were really very helpful. They said they would allow me to special order a 6-foot tank with a single center brace, rather than the two standard braces, but it would take them six to eight weeks to manufacture and ship it. As I was standing in the store trying to decide what to do, I moaned that what I really wanted was a nice old tank made out of thick glass without any braces.

Ned perked right up. “You don’t care if it’s new or not?”

“Not as long as it’s in good condition,” I replied.

It so happened that Ned had a 125-gallon tank in the store on a top rack. It was hard to get fish in and out of it because of the height, and he was happy to trade it for my shallower 100-gallon tank. In the end, it took longer to get this swap accomplished than it would have to order a new tank, but I am much happier with this nice old braceless tank with its half-inch thick glass. I’m not sure my husband and the other guys who had to carry this monster into the house were as happy as I was!

Now that I had all the pieces, it was time to get to work. The tanks along that wall were dismantled and the fish and plants shoehorned into two 30-gallon holding tanks in the basement. The cabinet and tank were put in place and carefully leveled. Next, we had our carpenter friend suspend the lights over the tank. The bottoms of the pendants are about 5 inches above the surface of the water. They would provide more even light moved up a little higher, but I didn’t want too much scattered light hitting the sitting area.

Because the ceiling studs were, naturally, not where we needed them to be to affix the lights, we screwed a long piece of wood into the ceiling studs, painted it white to blend in and hung the pendants from that. The lights are not that heavy, but there is no sense taking even a small chance on having an electrical device plunge into a tank full of water!

The ballasts for the lights were placed in the cabinet below the tank. They get slightly warm, but even during the summer they did not put out enough heat that it became a problem in the open-back cabinet. If there were a problem with heat buildup under a smaller tank, a small “muffin” fan would probably be sufficient to cool things down.

Next, we installed a narrow shelf behind the tank — about 6 inches below the top edge of the tank — to hold houseplants. I wanted to be able to take advantage of the light that would otherwise bounce off the white wall, and I also thought terrestrial plants hanging over the edge would make quite a dramatic display. Because my husband was already having a nervous breakdown over the strip of wood attached to the ceiling, we chose to actually hang the lightweight shelf on the edge of the tank rather than attach it to the wall. This works fine, but attaching it to the wall probably would have been easier! We used windowsill plant trays to line the shelf and catch the inevitable drips and overflows from watering the plants.

The next big question was filtration. Because I was trying all kinds of new things with this tank, I toyed with the idea of using an overflow to sump-style of filtration. The problem was, the more people I talked to, including those who were big fans of sump-style filters, the more horror stories I heard of large (or smaller) amounts of water on the floor. The other problem was that everyone I talked to mentioned the noise made by water in the overflow. There are ways to reduce this noise, but no one I talked to had been able to completely eliminate it. I wanted the tank to be a serene and quiet addition to the room, not a noisy distraction.

Between the noise issue and the fact that this is my hardwood-floored living room with expensive oriental rugs, I decided to forego the sump filter this time around. Probably more importantly, I would prefer to preserve my marriage. So I decided to stick with my tried and true Magnum canister filters. The slim black intake and return tubes of the Magnums are easily hidden and a couple of extra powerheads enhance water movement in this long tank. Using the Magnums also has made it easy to stick with my usual practice of using the filter return to power my CO₂ diffuser.

One of the disadvantages of an open-top tank is that it loses more water to evaporation than a covered tank. In a discussion I had on the subject with my friend Claus Christensen, from Tropica, he recommended keeping the tank temperature to within 10 degrees, Fahrenheit of the ambient room temperature to keep evaporation to a manageable level. While our daytime house temperature is about 68 degrees, at night the temperature drops to 62 or so. I decided to run the tank at about 72 degrees Fahrenheit. This put discus out of the running for tank residents, but there are many fish that are quite comfortable and happy at this temperature.

Another disadvantage of the open-top tank is that there is nothing to keep the fish in the tank. There are several strategies that can help reduce the loss of fish through jumping. The first is to make sure there are adequate hiding places for nervous fish or those that are feeling harassed. The second is to choose fish that are compatible and will not be likely to harass others. Certainly, it is probably a better idea to avoid species that are particularly known for their propensity for taking to the air, like hatchetfish and killies.

So far, I have not had too much trouble with jumping. I attribute this, at least in part, to the species I have chosen for the tank. I’ve been leery of introducing real surface-hugging fish and have instead chosen fish that spend more time in mid water or lower. The mid-water swimmers are a school of Congo tetras and a second school of Colombian red finned blue tetras. The Corydoras and Otocinclus catfish that inhabit the lower levels of the tank are not in much danger of turning themselves into fish chips!

I have lost two fish since I set up the tank — one Congo and one Colombian tetra. In both cases, it was a fish that had just recently been introduced to the tank and had not yet really settled in. If jumping proves to be an ongoing problem in an open-top tank, a 2-inch strip of glass cemented horizontally around the inside edge of the tank can effectively reduce jumping to a marked degree. Most jumping takes place when a fish runs the length of the tank, swims upward along the glass and jumps when it hits the water surface.

Another new adventure was ordering driftwood from Aquarium Driftwood in Alabama. My club had put together a group order with them about a year ago and I was very impressed with the pieces they sent. I called them up and told them I was looking for two pieces, one to actually reach up out of the water on one end of the tank and a second one, smaller, but echoing the first in shape, for the other end. I gave them my tank dimensions and how far I wanted it to stick out. They explained that for a large, special-order piece like this, they would have to actually go out into the swamp and search for exactly what I wanted. It was certainly worth the wait!

The driftwood I received is absolutely gorgeous. It was clean and thoroughly waterlogged, so it sank immediately upon arrival with no need to soak it or weight it down. It has not leached any discoloration into the water. Better still, it was very reasonable in price. It wouldn’t even be possible to get a piece the size of the larger one in a local pet store, and even the smaller one would have cost as much as my whole order if I had tried to buy it locally.

I was able to come close to fully planting the tank just using material harvested from my other tanks. The biggest plant in the tank is my huge old Rubin swordplant, which had been taking over my 70-gallon tank. Even in the 125, it fills about a quarter of the tank. I also received cuttings of several species new to me from a friend, including a nice Potamogeton, Hottonia palustris and Cyperus helferi.

The photo included with this article was taken about one month after the tank was set up. I went away on vacation a couple of days after the tank was set up and planted. In my absence, there was a problem with the way the CO₂ was being delivered. Essentially, the tank received no supplemental CO₂ during that period. I came home to find almost every surface covered with brown diatoms.

This problem was promptly resolved by ironing out the CO₂ delivery and adding a dozen Otocinclus catfish. All signs of the diatoms were gone in two days. There has been some filamentous green algae, but nothing of much consequence. The very slight clouding of the water seen in the photo was a mild bloom of suspended algae, which I removed with a micron filter. It has not returned.

The look of the metal halide lamps glistening down through the water column is lovely, and I am happy with the look of varying illumination in different areas of the tank. The light-hungry plants love it right under the lights, while the shade-tolerant species fill in around the edges.

As you can see, the terrestrial plants behind the tank are doing very well. They seem to benefit from the higher humidity just above the water surface. The foliage plants are doing extremely well. I am not sure whether the orchids are receiving enough light to re-bloom here, but if I find they are not setting new buds, I can rotate them back to their normal east-facing window, and replace them with others that are already in bloom.

The one problem I did have with the terrestrial plant arrangement was that I inevitably dripped water down between the tank and the plastic background sheet. This caused uneven contact of the background, leading to distracting color variations until it dried out again. I solved this problem by completely sealing the top edges of the background to the lip of the tank with clear plastic packing tape. Now any drips run harmlessly into the tank or into the plant behind the tank.

I hope this look at my new open-top tank and some of the decision making that went into setting it up will convince some of you to give one a try. It is a very beautiful and different look from our “standard” canopy style aquariums, and one I don’t think will disappoint you!