Newly planted Cryptocoryne lutea 'Hobbit'
Before: emersed leaves cut off

Jurijs Jutjajevs’ (of Tropica) has a “pro tip” for avoiding ‘crypt melt’ and getting Cryptocoryne species more rapidly adapted to submerged growth in an aquarium:  cut off all the emersed form leaves when planting.  It’s quite a dramatic thing to get your new plants in from the vendor and then immediately cut all the leaves off, but I gave that a try with Cryptocoryne lutea ‘Hobbit’ and it’s time to report the results.

In the ‘before’ picture you can see the stumps of the newly planted row of ‘Hobbits’ to the immediate right of the Lobelia cardinalis ‘Dwarf’ and to the left of a mature row of fully adapted submerged form Hobbits up against the glass.  The idea is for the new plants to focus energy on developing submerged form leaves straight away since there are no residual emersed form leaves left.  Another upside is not having to clean up the decayed form of the emersed leaves as the plant transitions.

Cutting off Cryptocoryne ermersed form leaves really works!

Pre-trimmed Cryptocoryne lutea ‘Hobbit’ six weeks after planting

Jurijs’ tip worked beautifully!  The newly planted row of Hobbits have in just six weeks grown fully adapted submerged form leaves and are already more than half the size of the Hobbits planted six months ago that had the emersed form leaves left on.  The new Hobbits have adapted so well and so quickly that it’s hard to visually pick them out behind the row of older Hobbits.

Non-pre-trimmed Cryptocoryne lutea ‘Hobbit’ six weeks after planting

When the emersed form leaves are left on at planting, there are at six weeks a few fully submerged form leaves present, but most of the plant is still trying to give it a go with emersed form leaves.  That might be a good strategy in the wild where water levels might fluctuate above and below the plant, but it won’t work long-term at the bottom of an aquarium.

Great tip for all Cryptocoryne species (except Cryptocoryne parva)

Jurijs says the tip works for all species of crypts except for Cryptocoryne parva.  Parva doesn’t change its leaf form between emersed and submerged growth, so there’s no need to ‘help’ it transition.

Special note:  also don’t try this with Cryptocoryne species grown in tissue culture form.

disposable CO2 gas cylinder
Clarke 600 g disposable CO2 cylinder

I ran out of CO2 gas today for the Fireplace Aquarium and swapped out the old CO2 supply cylinder for a new one.  I get 600 g CO2 at a time in disposable cylinders used for MIG welding, and sure enough, the empty cylinder weighed 1200 g and the new cylinder weighed 1800 g.

End of tank dump

I few weeks ago, I noticed the CO2 bubble rate had increased substantially due to increased flow rate through the regulator on the CO2 tank.  Regulators are the first step in controlling aquarium CO2 and regulators work best when the pressure inside the CO2 tank is constant.  Most of the time is this easy because inside the cylinder the CO2 exists in both a liquid and gas phase in equilibrium, and so long as there is any liquid CO2 at all, the equilibrium maintains a constant pressure in the tank of around 860 psi.  When the CO2 is running out, however, there comes a point when there is no liquid remaining in the tank at which point the pressure of the gas phase CO2 gradually drops as it is exhausted.  Single stage* regulators “notice” the pressure in the supply cylinder is dropping and attempt to compensate by opening more fully, however they inevitably over compensate resulting in increased gas flow even though the source cylinder is at lower pressure.  In some cases this failure of regulation can happen quickly and dramatically and can “dump” all the remaining CO2 gas into the aquarium, poisoning the animal residents (the plants won’t be bothered however).

With my set-up the regulation failure is not so severe, and can be easily mitigated by awareness a problem might be coming and by adjusting the flow through the regulator down a little on a daily basis until the cylinder runs out gas completely.  I get more than three months of constant pressure CO2 and then a couple weeks of manageable instabiliy at the end.  I’ve set a 3 month reminder for myself to remind me when to start carefully monitoring the end of this new cylinder.

*Dual stage regulator alternative

A dual stage regulator is designed to maintain constant flow even if the source pressure changes and can avoid the end of tank dump that can happen with single stage regulators.  Dual stage regulators are much more expensive than single stage, can be easily and erroneously confused with “dual guage” regulators, and don’t seem to be designed for the disposable CO2 cylinders I like to use.

Golden creeping Jenny in an aquarium

Also known as ‘moneywort’, the golden form of creeping Jenny came up in the weekly sales email from Aqua Essentials and even though I know impulse buying isn’t a good way to go with a planted aquarium, I was looking for a plant that gets to around 30 cm and the golden colour sounded appealing (and who doesn’t like 40% off list price?) so I picked up a pot.

The first surprise was the large amount of emersed leafy growth – six inches.  I don’t have any experience with this plant so wasn’t sure whether the emersed growth would simply rot away when submerged in the aquarium, in which case prophylatic vigorous trimming might be in order, or whether as a marshy plant the emersed growth would be ready for full submersion.  I decided to trim off any obviously rotted portions and the lower leaves near the roots so I could plant the stems to good depth, but otherwise to leave the emersed growth in place; this can always be trimmed off later after planting if not doing well.

The second surprise was that after prising away the rockwool growth support, there were nine quite vigorous looking individual stems.  The catalogs never tell you how many individual plantlets to expect from a single pot and nine is on the high end in my experience.  With a good amount of stems, planting in a row up against a side wall of the aquarium aiming for a “golden curtain” type of effect seemed feasible, so starting at the back on the left side I planted in a forward row as close to the tank wall as reasonably possible.

I’m looking forward to seeing how this new plant behaves.  The Fireplace Aquarium has developed into a multi-coloured live plant display with various shades of light green, dark red, blue/green, dark green, darkish purple and whitish foliage, and now hopefully golden yellow.