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Tank Log: Live Rock Curing |
I have about 150lbs of live rock in my current 70 gallon tank which I plan to move to the 225 tank. With the aquascaping plan I have, I figure I need an additional 150-200lbs of rock. I considered various sources and types of rocks and ended up deciding to have my LFS special order me some Fiji rock. I requested about 175lbs of mostly larger pieces. The order was placed on Monday 5/7/01 and arrived on schedule on 5/11/01.
When I went down to pick up the rock, my first though was HOLY SMOKES, this stuff is big! The weight came in at 206lbs and is composed of 11 pieces. This averages out to about 20lbs per rock. About half are closer to 30lbs and a few pieces are down around 10lbs in weight. No matter how you look at it, this stuff is pretty big. Cost is typically $5/lb. The request for specially collected large pieces added $.25/lb. The total bill came to $1079.00
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Here is one of the 4 boxes I received. This box weight was 60lbs and has 2 rocks in it! Packaging was simply a cardboard box with Styrofoam in the bottom, some plastic wrap and newspapers around the rock. |
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Here is a typical piece that I received. Due to the angle that I took the picture, the piece is bigger than it looks. |
Now it is time to get busy. I do not like to cure the live rock in the main display because I like to dispose of all the water used in the curing process and it also puts the tank at risk of getting scratched. I had previously bought a 50 gal Rubbermaid tub to cure the rock in and had set it up with saltwater, heater, power head and skimmer. I also had a bucket which I planned to use to pre-rinse the rock in. Due to the size of the rock, I could not fit most of the pieces in the bucket and there was no way I could stack all the pieces into the 50 gallon tub. I quickly pressed a 28 gallon Rubbermaid tub I had into service as well. I set it up with another heater, power head and pulled the skimmer off my 70. I forewent prescrubbing the rocks (no obviously dead stuff anyway) and placed the them directly into the tubs and started mixing more saltwater to get them covered. For the live rock curing, I am just using tap water that has been treated with dechlorinator. I am keeping the water temp around 78-80ºF
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Here is the live rock curing setup moments after getting everything setup last night. There are two tubs, each has a 250W heater, Maxijet power head and a skimmer. The gray tub has an old airstone skimmer and the clear tub has the venturi skimmer off my 70 gal tank. |
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Here is a shot that I took the next morning showing the first tub with the airstone skimmer setting on top of the live rock. |
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Here is a shot showing the second tub with the externally mounted venturi skimmer |
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Here's a shot of one of the skimmers doing its job. I have them both set to skim about a gallon a day to pull out as much junk as quickly as possible. |
Now that the curing setup is complete, I just need to monitor things until the curing process is completed. For this purpose, I purchased Ammonia, Nitrite and Nitrate test kits to monitor the nitrogen cycle in the curing tubs. For specifics on this, go to nitrogen cycle. The basic goal is get wait until ammonia and nitrite levels drop to zero, at which time I expect nitrates to be pretty high. The nitrates will be tossed out with the water when the rocks are placed into the display tank.
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Here is a shot of the test kits I use. I am a fan of Salifert test kits. |
As usual Murphy's law dictated that one of the curing tubs should spring a small leak on the second day, so I had to scurry down to the store and pickup another tub.
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Here is the new tub at work. Note the classy skimmer output diffuser (Tupperware bowl). |
I will be keeping a log of the daily water parameters in the table below. When I get enough readings, I will chart the nitrogen cycle process.
Live Rock Curing Chart
| Ammonia (mg/L.) | Nitrite (ppm) | Nitrate (mg/L) | |
| Day 1 (5/12/01) | 1.5 | 2.0 | 30 |
| Day 2 | 1.5 | 2.0 | 40 |
| Day 3 | 1.5 | 4.0 | 90 |
| Day 4 | 1.0 | 4.0 | 90 |
| Day 5 | 0.5 | 4.0 | 80 |
| Day 6 | 0.5 | 3.0 | 60 |
| Day 7 | < 0.5 | 2.0 | 40 |
| Day 8 | < 0.5 | 0.5 | 20 |
| Day 9 | 0 | 0.2 | 10 |
I have charted the values below. I have justified the ammonia and nitrite values up (x10) to give a clearer graph of the curves. The values on the Y axis are only relevant to the nitrate level. The absolute values are not important in this graph, it is the general trends that are of interest here. Also note that the maximum values tend to flatten out at the top of the curve and this is at least partially due to the fact that the test kits I am using are max'ing out at those levels and it is hard to get an exact reading.
Notice that the ammonia level starts out high due to the dead organic matter on the rock and starts to drop to zero over the course of a little more than a week. The nitrite and nitrate levels both increase for a couple of days, max out and then start to drop. It looks like this live rock will be fully cured within 10 days. One thing that surprised me is how fast the nitrates are also dropping.
