They say Cryptocoryne lutea ‘Hobbit’ is a small crypt, but saying it and seeing it are two different things.  This is a really small crypt!  The original idea was to have a small plant to go in front of the Lobelia cardinalis ‘Dwarf’ to hide the rooty lower stems of the Lobelia without covering up the pretty bright green higher foliage.  The ‘Hobbit’ is listed as a maximum height of 5 cm which sounded about right, but now I think that’s too small.  The ‘Hobbit’ adapted to submerged growth easily, but after a good number of months still ranges from 2-3 cm in height.  Further, the dark brown/purple coloration of submerged form ‘Hobbit’ gets lost against the dark colour aquasoil making the ‘Hobbit’ hard to see.  To top it all off, the ‘Hobbit’ became overrun by the Marsilea hirsuta carpet, which is about as tall as the Hobbit and spreads much more aggressively.

I like the ‘Hobbit’ but I don’t think it’s fit for the original purpose in the spot.  Accordingly, I decided to try the “next size up” in crypts, Cryptocoryne parva.  That left open the question of what to do with the ‘Hobbit’ so I’ve moved the Hobbit to the front and centre of the tank.

Cryptocoryne species have a reputation for ‘melting’ if they get traumatised.  In this case they shed all their existing leaves and make it a do-over with fresh growth.  I’m hoping that doesn’t happen with these transplanted Hobbits.  The aquasoil only very loosely holds the roots such that there wasn’t much root tearing, and the replanting procedure was more a nestle-in-place rather than putting them in a hole and covering them with dirt.  I’ll keep them free of Marsilea invasion and the new venue has more illumination as well since it is more centrally located under the light and isn’t generally overshadowed by any of the taller species:  Lobelia, Ludwigia and Lysimachia.

After two week holiday – no maintenance yet

We took a two week holiday and left the fish and plants in the Fireplace Aquarium on their own recognizance.  I did an 80% water change the day we set out, gave the fish a little extra food flakes, turned off the CO2 gas and otherwise left things as they were.  The fish, plants, fish and snails were all fine.  No casualties, and in fact everything was looking pretty good upon our return.  I had expected a huge algae problem to scrape off, but that was also fine.  Turns out these things are pretty robust.  You can buy “slow release” holiday food but I do not recommend doing that; for a couple of weeks, if everything is healthy when you leave, things will be ok upon your return.  Coming back, I gave the fish a slightly larger portion of food, did another water change, turned the CO2 back on and resumed EI fertiliser dosing.

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.

Fireplace Aquarium top down view during water change
View from the top during a water change

Unusual view* down into the Fireplace Aquarium during a major water change.  On the top of the mountain on the right is Bucephalandra caterina, with newly installed Anubias barteri nana ‘Pinto’ further down.  The flopped over red plant is Ludwigia palustris mini ‘Super Red’ with bright green Lobelia cardinalis ‘Dwarf’ just below it.  The low green carpet at the front is Marsilea hirsuta.  Very difficult to see are a few dark brown fronds from Cryptocoryne lutea ‘Hobbit’ at the front edge on the left side and a few sprigs in the lower right corner.  The built-in air lift tube from the underground filter system is the central whitish cylinder.  At the back from left to right are the drop checker, the heater and the powerhead.  

*It’s unusual because there’s not much overhead clearance between the top of the aquarium and the bottom of the chimney breast so it’s a little tricky getting a camera in there.

Today I shifted the location of the CO2 diffuser from the left wall of the tank to behind the moutain and underneath the powerhead.  The atomised CO2 gets sucked up directly into the flow and actively pushed around the tank.  Previously I had the diffuser on the opposite side of the tank hidden under the plants and whilst it seems sensible to put the CO2 where the plants are, because the flow pattern is circular, that puts the plants “upstream” of the diffuser last in the queue – the water has to do a full circuit to get back to them and by that time all the microbubbles have already reached the surface.  Those plants can still benefit from the dissolved CO2 of course, but they won’t get any microbubbles trapped under their leaves.  The diffuser is also now hidden behind the mountain, which is good, and is shaded by the powerhead to reduce algae growth on the diffuser, also good.

While I was moving things around and doing a cleanout I also took the opportunity to clean the diffuser by removing it from the tank while still active, layering on a few drops of liquid carbon, and letting that go for 10 minutes or so.  Back in the tank this increased the CO2 flow rate from 120 bubbles per minute to 130 bubbles per minute, so that worked well.

The fish seemed pretty happy about the whole thing but it will take a few weeks to get an opinion from the plants and algae.

Notes:  Cute video of a 5-banded barb swimming through the tunnel under the mountain.  The plant growing on the mountain is Bucephalandra caterina.  The carpeting plant at the base of the mountain is Marsilea hirsuta.

Nothing has really dramatically changed in the Fireplace Aquarium but I feel the green spot algae has been growing back quicker than it used to.  I was having to give the tank walls a credit-card scrapedown every three or four weeks, but now it seems up to every other week.  I tried increasing the dose of liquid carbon (a.k.a algaecide) from 1.0 ml per day to 1.5 ml per day, without noticeable effect other than using up 50% more EasyCarbo.  For sure though the hours of daylight are increasing rapidly now and even though the aquarium is 4m from the window, it is a south-facing window and bright all day long.  I’ve reduced the lighting supplied by the Tuna Sun LED light by reducing the period of full intensity light in the aquarium daily lighting sequence by 2 hours per day, so we’ll see if that helps.  I have long suspected that I’ve been providing more light than necessary so let’s give this a go.  I’m also going to knock the liquid carbon dosing back down to the original 1.0 ml per day.

Continue reading “Green spot algae in the summer”

Time lapse  sequence following major aquarium plant trim

About a month ago I revised the layout of some of the aquarium plants.  I didn’t like the look of all the stemmy/rooty bits of the Lobelia showing up against the front wall of the aquarium so I planted a row of dwarf Cryptocorynes in front to grow into a low cover.  The problem though was the lobelia were already crowded against the front.  When one of the lobelia plants came loose it was an opportunity for a do-over and I removed all the lobelia except the smallest plant closest to the left side and replanted lobelia trimmings taken from the removed mature plants in a line a bit farther back from the front wall.  Some of the ludwigia was also looking a little ratty with heavy algae cover on some of the lower leaves so I did a pretty aggressive takedown there as well.

Continue reading “Aquarium plants recover from trimming”

Aquatic plants for aquaria are commonly classed by how tall they can be expected to grow, with the idea that it is sensible to grow the shortest plants at the front of the tank, middle-sized plants somewhat further back behind the shortest plants, and the tallest plants at the very back.  In the community these are generally called, logically enough, foreground, midground and background plants.  Of course, you don’t have to follow this scheme and there might be a specific effect you’re trying to achieve by putting taller plants in front of shorter plants, but ideally this would be a deliberate choice and not something you unintentionally discover by accident.

In this video, you can see the effect in action.  On the left, at the very front bottom of the tank, low down and in the shadow of the lobelia, is a single dark green line of newly planted cryptocoryne lutea ‘hobbit’ which is expected to grow to a maximum of 5 cm.  The aforementioned lobelia cardinalis ‘wavy’, bright green and filling the bottow left quadrant of the tank, was planted six months ago and has topped out at its maximum height of just under 20 cm.  In the back of the tank, the red plant arching over the lobelia is ludwigia palustris mini ‘Super Red’ which would be around 45 cm if stretched out to its full length.  The very low carpeting plant on the right side all around the base of the mountain is marsilea hirsuta (although if you look carefully, there is another ‘hobbit’ hiding in the bottom right front corner.  The marsilea was planted over a year ago and will never get any larger than it is currently.  Some people like the look of plants that float on the surface such as frogbit or duckweed, and in a larger setup these can be effective, but I prefer not to go there in this instance.

I like the look of the different horizontal layers of plants on the left, contrasting with the verticality of the mountain sculpture on the right.  The fish seem to appreciate the differences too – if they’re nervous they can hide under the lobelia, or explore above the lobelia while still feeling a degree of sheltering protection (or at least so I project upon them) from the overarching ludwigia.

My daily lighting sequence with the Kessil A80 LED light controlled by a mains timer was pretty straightforward:  lights off for 18 hours per day and lights on full for 6 hours per day.  That’s fine but of occasion I’d head into work with the lights off and they’d already be off by time I came back home.  The problem is you can’t really extend the lit period very much before the algae starts to grow like crazy.  As a way around this I picked up a Kessil “Spectral Controller” which is a programmable timer that plugs into the light and lets you adjust both the light intensity and light colour throughout the day.

The video shows a looped simulation of my current lighting pattern – this is from the controller doing a “preview” of the programme so it’s very sped up and not done to time-period scale.  When I was using the mains timer, the “on” setting meant the light at full power (100% intensity) and a mostly white end of the spectrum colour (80% colour).  I like the look of that and the plants do well with it so I kept that setting for the main lights-on period with the spectral controller during the day.  I then added periods of extended low intensity on either side of the main lights-on period, and some gradual ramps up and down between those.  Brighter and bluer during the middle of the day, dimmer and redder in the morning and evening.

Current lighting programme:

  • 00:00 – 09:00:  lights off
  • 09:00 – 10:00:  5% intensity (lowest possible setting without turning off), 0% colour (as “warm” or “reddish” as possible)
  • 10:00 – 10:30  smoothly ramp up both the intensity and colour of the light to get to…
  • 10:30 – 15:00  100% intensity, 80% colour (the “on” setting with the mains timer)
  • 15:00 – 17:00  smoothly ramp down both the intensity and colour of the light to get to…
  • 17:00 – 18:00  5% intensity, 0% colour
  • 18:00 – 00:00  lights off

The extended low light periods are good for observation purposes.  The fish don’t seem to behave radically differently.  They still show the same lights on behavior vs. lights off behavior, but with some larger amount of intermediate swimming, particularly while the light intensity is ramping down at the end of the day.  It’s too soon to say whether the algae or plant growth will be different.

full height ludwigia and lobelia
Ludwigia breaks the surface

How tall do submerged aquarium plants grow?

Figures are approximate, as they say.  When planning a planted aquarium (and there should be some type of plan!) it’s important to consider the expected maximum height of plants in the layout.  I went wrong previously planting echinodorus radicans, a fine plant but much too large for this aquarium.

After not trimming back the ludwigia last week today it managed to reach the surface of the water.  This version of ludwigia, ludwigia mini ‘super red’ is listed online as “Dimensions: grows up to 30cm” however in this aquarium it is 41 cm from the aquasoil floor to the water surface, so this plant has overachieved.

I can’t complain and I’m glad it’s healthy.  I’ll give it a trim today and replant some of the better looking top portions to have it fill in a little to the right.  Stem plants like the ludwigia are pretty flexible that way:  you can trim them to pretty much whichever height works for you, just the growth rate and how much you trim will determine how often they will need this type of maintenance.

Afternote: 
Digging around a bit more on the Tropica entry for this plant it says in the “Plant info” section in the ‘Height’ entry if you click on the +/- expander button:

Height: 10 – 30+
Average height (cm) of the plant after two months in the tank.

so to be fair there is a little + sign after the 30 and it does say ‘after two months’ and it has been three months in tank (nearly to the day) since it was planted, so I suppose it’s “fair play” to the description, even if 30+ is actually 41…

Ludwigia palustris mini ‘Super Red’ can go back to green at the water surface

Just to see what would happen, another time I let the ‘Super Red’ go for much longer than I otherwise would have and it reached the top of the water and kept growing.  It kind of piled up on the surface without reaching directly through and I noticed that the new growth at the surface had green foliage rather than red.  When first planted back in the day the emersed form of the young Ludwigia was also green rather than red, and it seems the red colouration may be exclusive to the submerged form.  The pile of Ludwigia floating on the surface was shading everything underneath so I did eventually take it all out and replant the tops.  Ludwigia tolerates this procedure really well and I have successfully done this a number of times now without adverse findings.  Some of the ‘mini’ stems had comfortably exceeded 50 cm in length, so the ’30+’ guidance from Tropica could fairly be listed as 40+, or maybe 30+++.  Once back to being fully submerged, the new leaves produced subsequently were back to the usual bright red colouration.