WaterNotes

20: Eleven months

My experiments with carbon dioxide dosing, phosphate dosing, nitrate dosing, iron dosing (and the bioassays on a few invertebrate larvae to determine lethal concentrations) and other adventures continue. Unfortunately there isnt a whole lot to report this month!

The pygmy angel was added to the tank in the beginning of April after quarantine and she has proved to be an excellent marine planted tank addition. She’s a hearty algae flake eater and has completely ignored the seagrasses, decorative macroalgaes (green, red and brown) and picks only at the green glass algae. I was surprised to see her turn up her nose at Enteromorpha, which Scott Michaels (in his Angelfishes book) notes that Centropyge argi grazes on in the wild. But thats certainly okay with me.

The biggest news I have, really, is that I was able to get ahold of Halophila ovalis, also called oar grass or oar weed (and also spoon grass in some places) from Mary at seacrop.com. I wasnt too thrilled with packing practice, but the ‘grass arrived in perfectly okay shape and has been acclimating to tank life okay so far. Nothing really special to note, but it has shown rhizome elongation and a few new pairs of leafs, which are greatly stunted, but nevertheless green and overall healthy looking. Stunted leaves from Halophila is nothing new, consider the early shots of star grass from the 10gallon tank to see how small the initial leaf sets were after transplantation. I’m sure it has something to do with the plant drawing on internal resources to fuel new leaf development instead of actively processing nutrients via intact roots from the water column and/or soil.

Lets all cross our fingers and toes and hope that this species takes off. I also have Halophila decipiens, though I (argh!) still dont have photos of it because of the greenwater outbreak lately. H. decipiens, aka paddle grass, is very similar looking to H. ovalis and is also reacting to transplant with the same sluggish growth, stunted leafs and losing the wild leaves in the process.

Carbon dioxide dosing is still producing wonderful results in this tank. The left and right sides are now equally turning out new plants, potentially because rhizomes from the left invaded the right side and even started to lap the tank before I massively pruned the bed.

CO2 really needs to be shut off at night however. The biggest development in this month has been a greenwater outbreak at the last week. This is potentially attributable to a polychaete worm population boom in the tank and a depressed copepod population. But it may also be due to CO2 dosing at night, which was causing low pHs. Either way, overnight carbon dioxide bubbling will at the least cause hazy water, which isnt particularly desirable. I hope to get a handle on the greenwater situation soon so I can have some really good photos for all of you when the tank marks a big milestone in just a few weeks - it’ll turn one year old! So, turn off your injection at night folks!

Last month I noted that I had harvested over a hundred plants of shoal grass and couldn’t see any real differences in bed density with those plants harvested. I am now quite beyond that count, having harvested close to five hundred plants within the last month. If I didnt prune the tank it would be wall to wall Halodule wrightii! The Caulerpa prolifera has also done a very fabulous job in the tank and keeps pace with the shoal grass’ growth rates - about one to two new plants or leaf/fronds per day. Simply amazing.

Pics of the tank:

3.20.06

4.30.06

H. ovalis at lower right corner

Acetabularia sprouts on a chestnut turban snail