Posts Tagged ‘nitrogen-fixing bacteria’

The Post – Scarlett O’Hara “Labor and Delivery” Watch, and Ammonia Monitoring

March 27, 2008

For the last several days, Scarlett has been sitting on top of, or in, the water filter. Even though I shut down the filter Tuesday (so no babies would get sucked up in the filter material should they hatch), she continues to stay inside the empty filter. I guess it’s like a cave – nice and sheltered. She hasn’t come out to eat, but then I imagine that filter material has a ton of bacterial and algal critters all over it.

She DOES need to be in water at some point and on that count I’m not sure how long she can stay out of the water and in the filter. I tried chasing her out of the filter Tuesday afternoon, partially to see if she was okay, and partially to see if overcoming inertia and forcing her out would keep her out, but within minutes she was back inside of the filter. Who knows if she climbs out at night when the lights are off, to go for a swim.

Wed morning she was inside the filter, still sitting at the bottom. She wasn’t moving so I jiggled the filter cartridge enough to see her move. I left her alone until Wed afternooon when I pulled the filter cartridge up a bit. Scarlett O’Hara rushed up and out of the water filter and down into the water. She sat underneath the water filter, so I guess she’s just “staying put in sheltered places.” However, she does appear to be okay.

I tried giving her a couple of shrimp pellets, assuming she must be hungry, but she basically pushed them aside. She did pick at the calcium sand, so I expect she’s looking for algae. I dropped in a couple bits of algae pellets but she ignored those too. So either she isn’t hungry due to the pregnancy, something’s wrong, or she’s full from eating whatever is on that filter packing material. Right now she is still out in the tank and has even wandered over to the air bubbler at the other end of the tank. I am heartened to see her doing her usual activities: climbing up on the bubbler, trying to climb up the side of the tank, and resting on the suction cups behind the air filter that hold it in place. So, for now, I guess, all is well.

My only “curiosity” is “will she stay out into the water to deliver the babies?” I expect she will given that female fiddler crabs look for places in their estuary homes that have active water currents so the eggs can be washed out to sea. So “instinct” alone should propel her back into the tank water at about the time of delivery, no matter how much she likes it inside the water filter. Given she did it right the first time, I can’t imagine she’s forgotten what she needs to do. I missed the delivery the first time so I don’t know exactly what she does to release them. I hope I catch it this time. Also, I do wish I could just ask her why she likes living at the bottom of a dark empty water filter. In lieu of that conversation, all I can do is watch and wait…..

Water parameters Wed afternoon were good: Nitrates 10, Nitrite 0, Hardness >300, Chlorine 0, Alkalinity 300, pH 8.0 and the Ammonia monitor is in the “safe” range at < 0.02 ppm.

The ammonia monitor is a Seachem Ammonia monitor that you can hang inside the tank. No test strips or kits. This one is called the Seachem AmmoniaAlert for Fresh and Marine tanks. It continuously monitors the free ammonia level in the water for over a year.

The monitor is color coded for concentrations:

– Safe (<0.02 ppm), Yellow

– Alert ( 0.05 ppm), Green

– Alarm ( 0.20 mg/dl), Sky Blue

– Toxic ( 0.50 mg/dl), Lavender

The insert says that the “Alert Level” of free ammonia can be tolerated for several days; “Alarm” for a few days; and “Toxic” is rapidly harmful. It would have been interesting to see what it read when I had the phytoplankton overgrowth and high nitrites, the first time I did this.

While I knew that monitoring ammonia was important and somehow related to the level of nitrites and nitrates, I wasn’t sure exactly what was going on. I found a good website, The Tropical Tank, done in the UK, that discusses water chemistry, and in particular, ammonia, nitrites, and nitrates. It’s called: More on the Nitrogen Cycle: Ammonia, Nitrite, and Nitrate

In short, there should be no ammonia or nitrite in a mature tank. Any ammonia is present in two forms: ammonia (NH3) and ammonium ion (NH4+). Ammonia is more toxic than the ion, and the higher the aquarium pH, the higher the ammonia level. Since brackish and marine tanks are basic, ie higher pH, ammonia toxicity is a constant risk.

Ammonia in a mature tank is oxidized by nitrogen-fixing bacteria, to nitrites and again, in a mature tank, nitrites are oxidized to nitrates. While you don’t want to see nitrates run high, a lower level , say < 50 ppm, are considered okay, 25 ppm is even better. If your tank isn’t cycling well, is new and not enough nitrogen-fixing bacteria, you have too many tank inhabitants, or you’ve overfed them, ammonia (and hence nitrites and nitrates) will start to spike.

The bottom line, the appearance of rising ammonia levels is the first clue that things in the tank are not well and even toxic. Given that my last endeavor with crab larvae resulted in mass death due to high nitrites (and yes, the phytoplankton caused an algae bloom that caused ammonia and nitrites to spike and I won’t use it again) I thought it might be interesting to monitor the ammonia levels in the tank on a continuous basis through this project.

This article also gives information on how to start up the nitrogen cycle in a fishless tank. I wondered how you get the cycle going when there are no fish or fish wastes to start the process.

If you are interested, this same UK website has two other interesting articles:

The Basis of Cycling: a good overview of the maturing nitrogen cycle in aquariums

Fishless Cycling Data provided to them by a US forum member, William Wallace; some concrete data on how Mr. Wallace actually did this process.

To return to the tank and Scarlett:

Wed evening, the water looked cloudy and while other parameters were still fine, I noticed a trace amount of nitrites now. I also noticed a few green spots in the yellow safe zone of the ammonia monitor. The green spots are the beginning of a change to “alert.” Given that I think we’re a few days away from birth yet, I decided to turn the water filter back on for a day or so to try and improve the tank conditions. I suspect that adding Scarlett to the tank was enough to catalyze the nitrogen cycle into high gear. It’s to be expected to see “some” ammonia and nitrites, and there also is a “good” level of nitrates, but still, I don’t want to lose the battle of water quality before the babies are even born. I will continue to monitor water quality closely today today. If necessary, I’ll do some water changes, but I would rather not do that. Since the nitrogen cycle is in its early stages, every time I take water out and put in new water, it removes some of the very nitrogen-fixing bacteria I need. The gentleman at the aquarium store said it would be best to just let the tank evolve. So as long as we don’t go beyond “alert” on the ammonia monitor, I’ll let it “evolve.” Otherwise…I’ll have to start water changes. I wish I’d known earlier about the fishless cycling Mr. Wallace did. I could have done that with this tank to get the nitrogen cycle established before moving Scarlett into it.

Tank parameters this morning are the same as yesterday afternoon and Scarlett is out walking around the tank, so, no better, no worse.

Stay tuned.

The Post – Odd Goings-On in the Fiddler Tank – Is Scarlett Acting Pregnant Again?

March 16, 2008

When I first I walked by the fiddler tank yesterday morning, I was sleepy and oblivious. Then I did a double-take. Sitting at the front of the tank was the discarded molted shell of somebody. On closer examination, and with my husband’s consultation too, we both agreed it was Melanie Hamilton’s discard. That means she is at the moment most likely to get pregnant if Admiral Byrd invites her in.

At the same time we noticed that Scarlett O’Hara was sitting on top of the water filter….again. The last time she did that, we noticed shortly afterward that she was pregnant.

Admiral Byrd of course, was marching up and down the tank, claw arm held high, and waving.

To continue – Scarlett O’Hara spent the entire day and evening yesterday, on top of the water filter. She is still there this morning. She has never done that before or since, except when she was pregnant. I know she is still alive because she is “blowing bubbles.” Crabs foam sometimes when they’re out of water, to moisten their gills.

Even when I freaked out Admiral Byrd yesterday, and scared Melanie Hamilton out of her live rock because I was cleaning the tank and accidentally bumped the live rock, Scarlett O’Hara didn’t leave the filter perch. She just moved down into the filter for a bit, then climbed back up. Admiral Byrd meanwhile kept trying to climb the heater power cord up to the top of the filter to be near her, but he couldn’t quite do it with that large claw.

Yesterday afternoon we noticed that Melanie Hamilton remained outside the live rock, sitting there on the gravel serenely watching Admiral Byrd flex his claw. Then she spent the rest of the afternoon and evening in his cave lair. This morning she was resting just outside his lair, picking algae off the rock. He was napping inside.

With any luck, we can try the larvae thing again somtime soon?

I am in the middle of re-establishing the nursery tank. I had emptied everything from the original set-up, cleaned out the tank, put down the one inch or so of the calcium-releasing sand, and added the water. Now I did forget to rinse the sand out, so the tank water was cloudy at first, but it has settle out by now. I’m not sure how one effectively rinses sand out anyway without half of it going down the drain. I will say the white sand really makes the inside of the tank bright when the light is on. If we get babies again, it should be much easier to see them in such a bright tank.

I couldn’t decide whether to make the 3 gallons of water I added marine or brackish. I guess I should start brackish because first we’ll have to move the mom, whichever one of them it is, from their tank, which is brackish into this one. I wouldn’t want to shock them. Right now the tank is on the “marine side” of brackish. I’ll adjust the salinity with a bit more water shortly.

The live rock is back in the tank hopefully doing its thing to establish the nitrogen cycle. Both the air filter AND the bubbler are running and so hopefullly the tank environment will establish itself as quickly as possible. Rather than replace the old water filter cartridge and lose whatever nitrogen-fixing bacteria that had started to thrive in it, I left everything in place and returned it to the tank.

An interesting about the old water in that tank. I tested it before I emptied it out just to see if the nitrite levels ever came down. They read zero, and the nitrates were in the “okay” zone. I guess once I stopped using the live phytoplankton and let the water filter run for a few days, that was what it needed. So the phytoplankton was most likely the culprit in the high nitrites. In any event, I dumped the old water and just started with fresh sea/brackish water all over again.

One thing – that Reef Calcium product that I’d hoped would raise the alkalinity but not raise the pH, when added to half strength Instant Ocean… maybe it didn’t raise the pH but it didn’t solve the problem of the pH being too high from the Instant Ocean even when I used that at half strength. So I still had to use a pH lowering solution and this morning it is about 8.0 vs 8.4 that it was yesterday. So that’s perfect . At least though, the Reef Calcium did raise the alkalinity.

I will keep you all posted on any news from the adult tank. Keeping good thoughts for a new crop of larvae babies. Stay tuned.