Plant Growth problem

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Please Grow2

Aquarium Advice Apprentice
Joined
May 26, 2021
Messages
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Hi everyone. I'm hoping someone may have had similar experience and can help.
I have been battling to get my plants to grow for months, but am running out of ideas. I'm now down to the last possible thing left- changing my T5 lights.I have a 50 litre aquarium.
Here is a brief background to my efforts.
1. Started adding macros about 2 months ago. 30 ppm NO3, 3 ppm PO4, 20 ppm K. No effect.
2. Added 12 ppm Mg, via epsom salts. This did improve growth a little.
3. Switched to adding Fe-dtpa instead of seachem comprehensive about 3 weeks ago. Daily addition of 0.13 ppm as Fe, added after lights off, because fe dtpa photolyses rapidly in light. Some slight improvement.
4. Started adding Flourish Trace about two weeks ago. Addition every other day. Possibly some slight improvement.
Despite all this with slight improvement, my growth was not much improved.
5. Decided to push co2 rate up from 2 bps to 3.5 bps and increased lighting duration from 7.5 hr to 8 hr. Drop checker is pale lime green about an hour after lights on. CO2 comes on 1.5 hr before lights and off 1.5 hr before lights off.
Result = still pathetic growth rate compared to what I've had in the past.

Having exhausted the CO2 and nutrients, I'm forced to wonder if my T5 lights are the issue. They are nearly 3 years old. Many people on different fora say T5 lights never get old, but there are some people who think they do lose PAR and spectral quality. I'm wondering if they are right. I have two spare lights so I may try them and see. Nothing to lose I guess.
Any thoughts?
 
Hi everyone. I'm hoping someone may have had similar experience and can help.

I have been battling to get my plants to grow for months, but am running out of ideas. I'm now down to the last possible thing left- changing my T5 lights.I have a 50 litre aquarium.

Here is a brief background to my efforts.

1. Started adding macros about 2 months ago. 30 ppm NO3, 3 ppm PO4, 20 ppm K. No effect.

2. Added 12 ppm Mg, via epsom salts. This did improve growth a little.

3. Switched to adding Fe-dtpa instead of seachem comprehensive about 3 weeks ago. Daily addition of 0.13 ppm as Fe, added after lights off, because fe dtpa photolyses rapidly in light. Some slight improvement.

4. Started adding Flourish Trace about two weeks ago. Addition every other day. Possibly some slight improvement.

Despite all this with slight improvement, my growth was not much improved.

5. Decided to push co2 rate up from 2 bps to 3.5 bps and increased lighting duration from 7.5 hr to 8 hr. Drop checker is pale lime green about an hour after lights on. CO2 comes on 1.5 hr before lights and off 1.5 hr before lights off.

Result = still pathetic growth rate compared to what I've had in the past.



Having exhausted the CO2 and nutrients, I'm forced to wonder if my T5 lights are the issue. They are nearly 3 years old. Many people on different fora say T5 lights never get old, but there are some people who think they do lose PAR and spectral quality. I'm wondering if they are right. I have two spare lights so I may try them and see. Nothing to lose I guess.

Any thoughts?


That’s a lot of light for a 50 litre aquarium.

Also I don’t think you need that much po4. It could be precipitating the iron out of solution. Having said that DPTA is pretty stable at lower pH levels and pH is going to be low if you’re dosing whilst the co2 is running.

My tact would be to dose lower amounts more often and really split apart the dosing of phosphates and iron. Keep on top of water changes to improve oxygenation and replenish carbonates.

You need exceptional surface agitation as well. This is vital in any set up.
 
Hi Caliban07,
Thank you for your reply. Some extra information I forgot to include. I dose the phosphate only once at same time as 50% water change at weekends. Fe dtpa is added every day after light out. I have an external cartridge filter with co2 coming out of ceramic sinter underneath it, so it gets sucked in and dissolves before reaching outlet. In addition I have a internal cartridge filter with outlet just under surface. So, both filters provide a gentle rippling of water surface to oxygenate. The plants I have are cabomba, alternanthera cardinalis and crypts. The cabomba should be growing like crazy under the current nutrients and co2. But it's not.
 
Hi Caliban07,
Thank you for your reply. Some extra information I forgot to include. I dose the phosphate only once at same time as 50% water change at weekends. Fe dtpa is added every day after light out. I have an external cartridge filter with co2 coming out of ceramic sinter underneath it, so it gets sucked in and dissolves before reaching outlet. In addition I have a internal cartridge filter with outlet just under surface. So, both filters provide a gentle rippling of water surface to oxygenate. The plants I have are cabomba, alternanthera cardinalis and crypts. The cabomba should be growing like crazy under the current nutrients and co2. But it's not.


Hi Pal

Depending on how long the tank has been running there can be an adjustment period where things begin to stabilise. It’s normally after the violent algae stage that the plants begin to grow.

If the plants are not growing and/or wilting/melting then they are most certainly contributing to the Biological Oxygenation Demand (BOD) of the system. Oxygen is required for things to break down so when there are lots of things in the tank breaking down all at once whether it be fish waste, plant material, fish food etc the more oxygen drain there is on the tank. When the oxygen begins to fall important biological processes begin to slow down. When Iron oxidises it uses oxygen. So many things use oxygen which is why it is hands down the number one fundamental parameter in any system type.

My suggestion again is to replace water more frequently. By this action you are removing dissolving wastes and lessening the BOD. Turn that gentle ripple to to something more turbulent but without hurting the fish. An airstone is the best solution for this.
 
So, today I placed new T5 lights above the aquarium. After turning them on and waiting 5 minutes, I used a free App that measures PPFD. I obtained a max of 560 approx 5 cm below centre of luminaire. I have no idea if 560 is an accurate value or can be related to PAR. However, most importantly, I can compare the value with the old T5 lights, which had a max of 382 doing exactly the same method. Later I will assess the number after lights have been on for 2 hours. If the difference remains the same or thereabouts, then I have objective proof that the new lights are about 40% brighter with respect to whatever this APP is actually detecting. The next test will be to observe if this final change to the tank conditions will cause a noticeable increase in growth of plants.
 
I had noticed that new t5 bulbs cause algae for a month or so and I’d have to look back but were brighter I think from Seneye par readings.

I was never quite sure if spectrum shift occurred as bulbs aged (or if it made any difference).

Bulbs in mine must be about 3 years old as well but I’m only chasing slow growth. And have an LED light as well.

When I was chasing better growth I’d decided that replacing bulbs every 9 months was ideal (not much science to it and was keeping wallet happy as well as pretty expensive).
 
Hi Delapool,
It will be interesting to see how the plants respond now. Because I was convinced it was nutrients and/or co2, I've already pushed all of them into more of an EI approach for nutients and I have co2 at 3 bps into 50L tank, with drop checker pale lime green within hour of lights on. Despite all that, growth has been painful! So, I'm hoping it is the lights that are holding things back. Interestingly last night (day 1 of new lights), I noticed one of my alternanthera cardinalis leaves pearling, just two inches above the substrate. That could be a sign, perhaps blue light in new lights penetrating deeper into water. This might suggest that the difference in my light intensity picked up by my APP might be down to loss in the blue part of spectrum. BUT, I can only speculate because I don't have the equipment to measure spectral emissions.
 
Be interesting to see how it goes. Same thought as above I guess - that you have enough flow to push the CO2 around? As assuming so on a 50 litre tank?

Also are these T5 high or normal output? I’d have thought tank wouldn’t be too deep but thought to ask.
 
Hi Delapool,
The T5 are high output. ( sunwave 21 watt, 24 inch, 12000K).External and internal pumps. Co2 comes out of ceramic mister directly under input pipe of external cartridge filter, so very efficiently dissolved before coming out via outlet on other side of tank. Drop checker positioned just above substrate in corner opposite to outlet of cartridge. Hopefully that indicates it is spread evenly around tank ( although only way to prove that is another drop checker placed somewhere appropriate). Day 2 of new lights, I checked value on my PPFD APP and it showed 492 max at centre, 5 cm below lights after several hours of coming on (having dropped from initial max of 560). So, identical to day 1. This looks like my baseline starting point, for future checks. If I do get a surge in plant growth, then I can correlate any future slowing down against a drop in that value.
 
Go to play store, and look for ppfd. You'll know which one it is, as it has lots of good reviews and even some comments about good comparison with PAR meters!
 
Update. So, 1 week after new lights, issues continue with green spot algae growth on my alternanthera leaves. Growth in tank still less than hoped. But last night, I did notice some new tiny leaves growing out of a leaf internode on one of the alternanthera plants. That's the first time I've seen this happen since my troubles began. Maybe this is the first sign of something good..i also cut the lighting period to 6 hours three days ago. I will do a 50% water change today, cut off the algae covered leaves, and continue with my daily dose of 10 ml excel, which I have determined over many years is the optimum safe dose ( for my specific tank inhabitants) to inhibit bba. Does not kill it when added to whole tank, but does stop its spread. I hope my changes I have made over last few weeks ( increased co2 3 bps, higher NPK + Mg, daily Fe-dtpa and seachem trace (3/wk) in addition to new T5 HO lights) to my 50L tank, will soon show major improvement in plant growth! My guppies are breeding like crazy! But it's always been much easier to look after the fish, compared to my plants!
.
 
Update, 2 weeks. Ppfd value 472. Slight drop from 492, on day 1. Green dust algae still a pain on alternathera leaves. Some new red leaves have been produced, but still waiting for signs of growth spurt. The last two weeks have had good co2, ferts, and light, but maybe it will take longer before effect is seen. Today, dropped light period to 5.5 hr to try and hold back green algae. Scraped algae off glass and removed leaves with algae. Upped excel to 15 ml per day, to hold back bba, which still lurks from the last battle. Hopefully, I have found a window of conditions, that allows plants to grow better than the algae. Guppies breeding like crazy! None of the particular fish or amanos are affected by excel at this dose, based on past experience, even for many weeks of daily dosing, so I'm happy to maintain this level (15 ml in 50 L, about 2x dosage rate at water change). However, people dose at their own risk!
 
Update after 3 weeks. Still not seeing the growth expected. After one week of 5.5 hr light period, green algae growth has reduced. I removed far less leaves during water change yesterday. Decided to do major cleaning of external and internal filters, pushed syphon tube about 1 cm into gravel, which sucked up lots of sediment, and turned heater off. These changes are intended to reduce oxygen demand and to try and keep co2 and O2 in solution to higher degree. I intend to make two water changes per week at approx 50%,each. During this period, traces, macros, co2 bps and lights will remain fixed at same level as last 3 weeks, so if a significant increase in growth is obvious, I can conclude it was something related to water changes and/or drop in temperature and/or cleaning filters/ gravel. Sooner or later, I will find the issue! Oxygen demand was mentioned to me soon after I made first post: I'm wondering if they were right, but I needed to rule out the usual causes first, which are insufficient co2, lights, nutrients. I think I've done that now. But, the changes I'm doing now, if they work, would rely on good co2, lights and nutrients! So,, we will see what happens....
 
Update week 4. Green algae still a pain, mainly on leaves of alternanthera. Growth still poor. Did 40% water change mid week. Now deciding to add seachem traces every day, but will reduce iron to 0.05 ppm per day. One thing I have noticed, is that a leafless algae- covered twig that I was going to pull out last weekend, but decided to give it another week, has suddenly produced a small red leaf halfway up the twig. And possibly another tiny red leaf is growing out of the top. So, that is promising. For the next week, will continue with two water changes, reduced iron, but daily trace. Oh, forgot to mention, I stopped dosing with excel during last 7 days. Trying to control algae by attrition and light reduction. Ppfd 475. So, light intensity remains same as two weeks ago.
 
Have a look at this thread at the bottom. Swamp Mike did one of the things many people don’t. He waited and waited and waited. Now he is seeing the tank transform.

I’m telling you bud. Everything you are doing is not going to make the tank mature faster. It will mature when it is ready. You have to wait for the biofilter to fully establish. THEN the algae will die away and the plants will begin to grow. Have faith.

How Long to Establish Plants?
https://www.aquariumadvice.com/forums/showthread.php?t=376290
 
Hi Caliban07
My aquarium is many years old so my filters are mature. I have external and internal filtration. But for some reason plants just stopped growing. Last year, growth was so fast, the tank was full of leaves. This is why it is so strange and I'm hoping to reset the conditions. I have a large number of fish and they are healthy, so I doubt the number of bacteria is insufficient. It's a big mystery. I have heard stories from other people who have experienced similar issues, suddenly seeing growth stop. I was interested in your original advice to reduce bioload, in order to increase O2 and I cleaned all filters, sediment and moving to double water changes to see if this helps.
Thanks,
 
You said the growth rate was high last year and implied that the plants "took over the aquarium." If so have you cut them back significantly? Surely growth naturally slows to a near halt when the aquarium is crowded with foliage. A 50-liter tank is quite small.

Fluorescent lamps to include T5s do lose intensity over time so your tank is readapting to a sudden change. I suspect that your rather radical changes in doxing/fertilization are doing next no nothing.

You need exceptional surface agitation as well. This is vital in any set up.

Do you have the above? A bubble wall at the rear or sides works very well.
 
Hi. Thanks for your reply. Yes, I cut back growth radically, but at some point growth slowed, but aquarium is not full of leaves at the moment and hasn't been for months. For surface agitation, I have the outlet of an external canister, about 2 inches below surface and an internal filter on opposite side of tank with outlet about 1 inch bow. External canister has 5 x tank volumes per hour flow. So, I think surface agitation is as good as in the past, and I've had the same setup for many years. I've added some elodea and egeria this weekend to try and increase oxygen into tank.
 
There's nothing so good for surface agitation as gas bubbles breaking at the surface. No air stones/bars?

Did your plants get to mature size in a 50-liter aquarium? If so a radical pruning may have stunted them severely as may vigorous growth pruned radically before the plant is truly mature.
 
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