WaterNotes

The twenty gallon approach

I love the new tank, even though its still in its infancy and just completed cycling earlier this week. I transferred all the mud and sand from the old tank into the new and added an additional 25 lbs of medium grained CaribSea aragonite on top (Flamingo pink!) to bring the sand bed to 5″ sloped at the rear to 3.5″ at the front. The slope allows for the shorter plants, which also have slightly shallower roots, to crowd nicely in the front. I also supplemented the mud/aragonite bed with broken up Seachem Fluorish tabs to help along a good strong thick grass bed. Previously I used Jobes’ fertilizer spikes for green houseplants, but because I’m wary of ammonium in the formula sparking algae outbreaks, I went with the Seachem instead. These dont have phosphate or nitrate in them though, so I still have to dose this.

While setting up I realized just how much growth I’ve had out of all the plants in the old ten gallon. The stargrass, when I first got it, was barely four colonies of six or seven really terrible looking leaf sets. I had veritable garlands of stargrass with growing tips shooting out from all over the place off the main rhizomes. I planted the new sandbed and discovered I had several feet of leftover ‘garland’ and traded out plants of the stargrass. Man this stuff is prolific!

The stargrass did, however, take quite some time to really settle into the new tank. I think this is somewhat due to the cycling environment the grass didnt encounter before and some strong competition from various algae’s, but more on that in a bit. It took two weeks before the stargrass was sending up new shoots and the largest sets of leaves, mostly those with flowers previously, died back rather aggressively. At one point I was scared I was going to lose the species entirely in fact. It has, however, come back pretty strong and I think in another month I’ll once again be in the position of being smothered by these little guys.

Bill from Bill’s Reef was nice enough to send me some turtle grass, Thalassia testudinum, which has made a gorgeous addition to the rear of the tank. It settled in nicely after undergoing a freshwater dip for hydroids. However, even at 5″ I’m not sure that the sandbed is sufficient for the turtlegrass.. some of the parts of the plants that looked to be embedded before collection are now exposed. Time will tell what this does to the plants. Also, they are actually a lot bigger than I had previously imagined. We’ll see how things look when the shoal grass decides to kick in and produce more plantlets across the mid-ground. But, I may come to regret that this tank isnt a 29-gallon with that bit of extra height.

The turtlegrass has also taken a long time to settle in, I’ve had it two weeks now with only minimal growth and a lot of leaf death. The manatee and shoal grass have likewise taken the transplant rather hard. Now I know why its so difficult for people to recover lost wild seagrass beds by transplanting! Even in a controlled tank environment they are hard to get to recover. Honestly it seems that the interlude between transplant and death or growth has more to do with the plant’s roots than anything else. If they are heavily damaged the plants put a lot of energy into growing them back and, if they cant devote time to photosynthesis, dont seem to survive. Something to consider if you’re planting seagrass then, is to pay attention to the root structure and to attempt to be as delicate as possible with it.

For the rest of the livestock, I now have a nice culture going of grass shrimp, Palaemonetes vulgaris, which are the saltwater cousins of freshwater ghost shrimp. A few adults of these were also added to the tank for scavenging and such. I found I’ve grown attached to the one I initially brought back in early March from the IRL. He was my only real livestock for months! I had some Nassarius vibex snails in the tank but found them munching stargrass early one morning, after they had polished off some nice macroalgae from the bay, and I sent them packing.

The most interesting and recent addition to the tank is a fighting conch, Strombus alatus about two weeks ago. He was actually in the tank during the last stage of the nitrite spike which I hadnt realized at the time. Poor baby, but he’s a champ and looks great. He was, however, only of minimal help in combating the various algae plagues and is really more for decoration than anything else. At 1″ I’m not sure how long he’ll last in the 20gal but time will tell how fast his growth is. At least he fits neatly into the biotope!

Speaking of algae, there has been a noticeable progression of algae in the tank as it first established. In fact, at the conclusion of the cycle, when the plants began to aggressively suck out the nitrate levels, all the algae besides a light green glass algae have vanished. I’m starting to believe that the green haze is actually a sign of a tank in good health.

As you might expect in a new tank, diatoms broke out with a vengeance the first week or so and then died back on their own. The green glass algae has started to come back, but its only a slight haze within a weeks time - nothing too aggressive. The diatoms pop back up only when carbon dioxide levels fall in the tank. This is usually the case when a) the skimmer is tuned too low, b) the powerheads are getting clogged or c) there is so much photosynthesis going on that I cant provide enough carbon dioxide without injecting it, period! Additionally, around the third week of the four week cycle, red slime (cyanobacteria) popped up to say hello. I was able to fight that out in a week’s time by pushing nitrate pretty high (30ppm), pulling out rocks that I was convinced were leaking phosphate into the water, and doing a light vacuum. The cyano bit the dust in six days!

Which brings me to my new project on the horizon - injecting CO2 into the tank, either by pressurized tank or by a DIY setup with a yeast reactor - once I get a high density of plants going again. Honestly, in a very high density plant environment, it doesnt seem that you can get away from high pH issues without lots or aeration or possibly injecting carbon dioxide. This should be pretty interesting. If you recall I already dabbled with this, but found it dropped the pH too low in the tank, about 7.6 or there abouts. However, that was way before I had really high plant density. I’m excited about attempting it again.

Now that the cycle’s over, and my trip back to the IRL is just a week away, I can hardly contain my excitement. The best stage of a planted tank - and one in which all of mine have terminally occupied - is establishing a good and interesting aquascape with healthy and beautiful plants. On the list to bring back from the Keys include mermaids wine glass, Ochtodes, Halimeda, and some of the other gorgeous beauties in the new book I got - Marine Plants of the Caribbean. Oh, and of course, those little seahorses I have been anxiously awaiting for eight months. (Though they’ll actually be captive bred.)

Till next time, happy underwater gardening!

The new setup’s progression since 6.1.05:

6.4.05

6.15.05

6.28.05

Turtlegrass exposed