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Why are my 'easy to grow' plants suffering?

Tresbling

Member
Joined
15 Feb 2008
Messages
49
Hi,

I am beginning to have success with my planted tank now, but my so called 'easy' plants are not growing. I have Hygrophila siamensis at the back and it has hardly grown in 3 weeks, and looking a bit pale. I also have a small amount of Salvinia natans at the surface and it is turning brown and dying.

However my glossostigma, lilaeopsis and nymphaea stellata are all growing fast and lush.

4.4g, 2 x 11w compact, DIY CO2, fert substrate, trace dosing only, small frequent water changes, low fish load.

Are the plants experiencing photoinhibition from the high WPG? Ive grown them well in low light tanks.

Or are they indicating that there is no NPK in the tank? I will start dosing TPN+ as soon as I can get hold of some. Will this solve the problem?

Any help much appreciated.
 
No, in this case the plants are not suffering photoinhibition from the high WPG. They suffer growth inhibition due to NPK starvation under high WPG. Is that 22 watts T5 CF? If so that is a lot of light for a 5 gallon tank. Dosing NPK should help.

Cheers,
 
I have what is believed to be H. siamensis and it would appear to be exactly like yours. It has grown (slowly) but it's quite pale, although I had it floating in my tank for a week or so before I had time to plant it properly so I just assumed it was recovering. Interesting about the NPK as I haven't started dosing that yet either, partly due to me just not getting round to getting any and partly due to the thought of "I wonder what will happen if I don't?" (don't answer that Clive!)
 
Well as a 'fishkeeper' new to planted aquaria I find it odd to put nitrate and phospate INTO the tank rather than try to remove it! None of my local shops sell NPK fertiliser, looks like aquaessentials is the way to go.

One of my ottos died and was missing for a few days before i found him at the back of the tank, and as a result the plants seem to have really grown quickly as the fish polluted the water! Maybe thats an indicator that i should dose...

Yes i have 2x T5 power compact bulbs over an 18cm water column, but one is on for 12 hours and the other just comes on for 6 hours in the middle to get the glosso going. But the glosso seems to be growing happily and flat in the shaded parts, so perhaps i dont need all that light.

Cheers
 
Hi,
No you don't need all that much light. As with all carpet type plants Glosso requires high CO2 and nutrients, not necessarily high lights. Because your tank size is low, the distance from the light bulb to the Glosso is very shot so it's easy for that plant to get sufficient light. The Nitrate and Phosphate haters are ill informed and have been so for generations of fishkeeping. It is not the NO3/PO4 that is so dangerous to fish but the ammonia and organic waste that they start off as.

The chloroplast in plants that are used to collect and process light can only be fabricated using Nitrogen, so nitrate is crucial. The starch, or sugar that is produced by plants using the energy of the sun captured by those chloroplasts is a phosphate sugar. The biochemical energy produce in every living cell of a plant can only occur as a direct result of phosphate enzymes and phosphate proteins. The more light you add to tank the higher the levels of NPK required for growth. So anyone who thinks they need to eliminate PO4 from a planted tank is in for a real struggle. The paranoia surrounding NO3/PO4 is what has arrested the development of the planted tank hobby for so long. Think of dosing NPK + CO2 in the same way you think of eating food. Think of water changes in the same way you think of flushing the toilet. :D

Cheers,
 
Hey thanks,

I got my hands on some TPN+ and as if by magic, my plants are all green and growing fast. :D

Ive noticed some algae growing since dosing, on the larger leaves and bogwood. I think its green brush algae, its small raised green tufts. I guess this a response to the sudden rise in NPK, as the algae can respond quicker than the higher plants. Should I scrub it and hope it doesnt come back as the plants adapt to use all the nutrients, or is this a clear sign of overdosing?

Im dosing 0.3 ml per day, assuming its better to dose little and often to give more stable levels.
 
Hi,
You need to change your mindset so that you stop linking algae growth to nutrients. If algae appears then it's because of a rise in ammonia content not because of nutrient content. Stable nutrient levels are a nice idea but it is more important to ensure that you have have sufficient levels. BBA is a CO2 issue. You therefore need to improve your CO2 level and distribution quickly. Again, lowering the light will help to stem this tide. DIY CO2 under high lighting is cause for concern so you may need to supplement your CO2 with Excel/Easycarbo.

Cheers,
 
It may be that the dead otto and resulting ammonia spike triggered the algae. It is now taking advantage of the lovely food you're adding. If you increase your frequency of water changes and remove as much of it as possible each time it should die back/stay away.
 
The otto is removed now I must stress! :D

I removed the algae and cut down the hours that both my lights are on. Also thinking of 'daisy chaining' 2 DIY yeast bottles. Bad idea? (im a student and can no way afford pressurised)

There has been huge improvement, its just a tiny bit of brush and spot algae, and there has been no slime algae at all since dosing, which used to get everywhere- amazing that adding N and P actually removes algae!
 
DIY CO2 can be a contributing factor to the rise of BBA. The reason being that unstable CO2 levels can trigger BBA and DIY, if not properly managed can cause this instability. I'm not a DIYer so I'll let someone else advise but daisychaining sounds like a good idea to me. High stable levels of CO2 are required. Spot algae means you need to add more PO4 generally but that is not the big problem. The BBA is the big problem so focus on CO2 improvement.

Cheers,
 
Tresbling said:
...There has been huge improvement, its just a tiny bit of brush and spot algae, and there has been no slime algae at all since dosing, which used to get everywhere- amazing that adding N and P actually removes algae!

Another mind freed from the slavery of The Matrix... :D

Morpheus to Neo: "Welcome to the Real World"...
 
Thank you Morpheus! Can I go punching through walls now? :D

Just revising stoichiometric phytoplankton models for my finals now, wish I could have a similar breakthrough there!

Do you reckon just 1 x 11 watts for 12 hours would be enough for the glosso? The tank looks too bright and washed out under 2 lights anyway...

Thanks for all the help BTW, my tank is much better now thanks to ceg and all the ppl on this forum!
 
Tresbling said:
Do you reckon just 1 x 11 watts for 12 hours would be enough for the glosso? The tank looks too bright and washed out under 2 lights anyway...

Yes, I sure do. A 5 gallon tank doesn't need all that energy input. High energy input creates a high CO2/nutrient uptake demand, as well as a high organic waste output and thus higher maintenance requirements. By using only a single bulb you would give yourself a lot more breathing room.

I'm confident you'll do well with those phytoplankton models mate. Good luck. :D

Cheers,
 
You've reminded me of something there Clive, because we are partly to blame - in very own UKAPS poster here:

http://www.ukaps.org/documents/FAQ Poster.pdf

We say for tanks less than 40L 1 watt per litre is required. I'd say you still only want 0.5 watts/litre right down to at least 18 litres. Smaller than that I don't have the experience to say. I wonder if we could agree some more suitable advice - Tresbling is not the only poster in the last few weeks running waaaaay too much light on a small tank.

Tresbling - I think 11watts for 9 hours would still grow your glosso, and daisy chaining two bottles will help cut fluctuations if you alternate bottle changes, for example one every 3 days rather than just once every 6 days.
 
Yeah Ray, it's a bit of a conundrum. Certainly if you have pressurized CO2 and if the injection rate is adequate then it's much less of an issue. To be fair, the poster also addresses the importance of fertilization and CO2 application as well as the light-CO2-nutrient linkage. Maybe we need to think about the per litre value some more though. :?

Cheers,
 
Im no good at maths but im sure you guys could come up with an 'aquarium light calculator'.

Like the volume calculator but you plug width x length x (water depth - substrate depth + height of bulb above surface) and what lights youre planning to use, then it cleverly churns out a photon flux density for your leaf surfaces, using extinction values + reflection + refraction or whatever you need?

Then you could have a table of CO2 and fert levels to help you work out where to go from there...? Anyone keen?
 
Hi,
Unfortunately that would be tougher than your stoichiometric phytoplankton models. The photon flux density at any particular x-y-z coordinate within the given volume depends on a lot more than just the bulb flux density profile. There is reflection from neighboring surfaces, and the substrate as well as ambient light entry from the sides and front (or rear depending on background). It also depends on existence of or type of reflectors. Even the type of plant changes the equation - some plants have a highly reflective pigments on the abaxial surface of the leaf while others have a dull or neutral color. The flux density changes daily as the plants grow as well so one would only be able to specify a profile for a standard bare tank under certain very restrictive conditions, which wouldn't be of use to any other configuration. Just having a light colored substrate like sand versus a dark colored one like Amazonia can change the profile. Wpg, as crude and inaccurate as it is, still is a better general guide. It's just a matter of learning how not to go "over the top" with lighting. As much advice as I give about keeping the lighting low, I'm actually the worst offender I know. :lol:

Cheers,
 
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