Dying Forgbit and Algae

[jameson_uk]

TLDR: I need suggestions on why Amazon Frogbit died and how to get tank back on track

I have a Rio 180 tank with the stock 2x45W T5 tubes running in an otherwise low tech setup. It is reasonably well planted (Amazon Swords, Crypts, Rotalia, Fotala, Anubias and Java Fern) just adding Flourish once a week and Tropica root tabs (mainly micro plus a little macro I believe) where appropriate once every six weeks or so.

The tank has been setup for nearly five months and whilst I have had a few issues with plants not growing that well (http://www.ukaps.org/forum/threads/deficiencies.42284/) they have been not that bad. I upped the lighting to a contiguous 8 hours a day (from 2 x 3 hours) and the plants looked a bit healthier and I have had to trim the stem plants quite a bit and the swords look a little healthier and there is generally growth everywhere.

From other threads I realise this is probably too much light but as the lights are built into the lid there is little I can do about this until I can afford to look at other options (the T5s are an odd length to only a couple of possible replacements and these are still 45W and you cannot run the unit with just one tube).

The frogbit I added about four months ago has been growing pretty well and I have been using this to diffuse the light and has been doing pretty well. I put in about 10 medium plants and these all grew and spread quite well to cover about 20-25% of the surface but started dying off a few weeks ago it looked like

The plants still looked relatively healthy but lots of leaves were falling off some of which looked perfectly healthy, others has basically decomposed and others looks like they had chunks taken out of them. I suspected some of this was down to flow and the leaves being forced under water and rotting so I had tried a few things to keep them out of the main flow from the spray bar without much change.

I have come back from a week's holiday and a significant amount of frogbit seems to have disappeared (probably covers less than 5% now)


On top of this I have a lot more algae than I had before.
I have not really had any algae of note on the front glass (and the small amount that was there previously was quickly removed by the Otos). There is now a fair amount of green algae and the dark dots are what I believe are tufts of BBA.

On top of this the Java Moss which has been fine has developed a mass of thread algae

which has basically developed over the last week.

Some of the fish have been suffering from Flavobacterium columnare (Cottonmouth) which had a few impacts starting two weeks ago

• Did a couple of fairly big water changes (which brought nitrates down to about 10ppm)
• Treated with Interpet No 8 (Anti-fungal & finrot) which is also apparently anti-bacterial. This did not go too well and it knocked a lot of the fish out so ended up doing another fairly big water change and I think Nitrates dropped to 5ppm)
• Dropped the temperature down to about 23.5C (apparently this stops the spread of the bacteria)
• Removed the Purigen that was in the canister

I then left for holiday last Friday doing a normal 30% water change, dosing Flourish as normal and upping the temperature to ~25C.

The in-laws popped round on Wednesday and fed them (amounts I have already measured out).

Today I got back and found one of the rainbowfish dead (looks like it was one that had the bacterial infection) and all this algae....

So what looks to have happened to the frogbit and why was it OK until a few weeks ago?

Going to be a doing a fair bit of maintenance tomorrow and will try and remove as much algae as I can but could do with understanding that is going on...

• Could the reduction in Phosphate (only been fed twice this week) cause an issue?
• Is there an obvious deficient you can see from the frogbit pictures (I did see Iron mentioned somewhere)
• Could the big reduction in nitrates have caused an issue (had been staying fairly static about 20ppm)
• Could the removal of the Purigen actually helped the algae?

 

[dw1305]

Hi all,
The algae is probably because more light is reaching the tank, now that the Frogbit has died off. Because the Flourish doesn't contain much nitrogen or phosphorus (or potassium?) it is most likely to be a deficiency of one of these elements. They are all mobile elements within the plant, so would effect older leaves. Iron deficiency effects newer leaves, because it isn't mobile.

There would be no reason why you can't be deficient in more than one element.

cheers Darrel

 

[jameson_uk]

Hi all,
The algae is probably because more light is reaching the tank, now that the Frogbit has died off. Because the Flourish doesn't contain much nitrogen or phosphorus (or potassium?) it is most likely to be a deficiency of one of these elements. They are all mobile elements within the plant, so would effect older leaves. Iron deficiency effects newer leaves, because it isn't mobile.

There would be no reason why you can't be deficient in more than one element.

cheers Darrel

So the question is what changed as it was growing quite happily. My guess is that increasing the light got the stems growing faster which has meant I have had to trim and replant so are these now using up all the nutrients?

I thought in a low tech setup N was normally sufficient from the fish and the main source of phosphate was fish food?

Am I right in thinking it is not really worth/possible to test for macro elements so might as well just add them ? If so what is the easiest method? Ideally I want to keep to a weekly schedule and a lot of the EI type dosing talks about daily dosing (and is based on high tech tanks)

 

[dw1305]

Hi all,

Am I right in thinking it is not really worth/possible to test for macro elements so might as well just add them ? If so what is the easiest method? Ideally I want to keep to a weekly schedule and a lot of the EI type dosing talks about daily dosing (and is based on high tech tanks)

You can just carry on using your Frogbit as an indication of when you need to feed. I started using Lemna as my indicator plant (hence the <"Duckweed Index">), but there are advantages to using Amazon Frogbit.

Because floating plants have access to atmospheric CO2, and light directly from the fixture, any problems with growth will relate to nutrient level, or availability.

Plants need varying amounts of all the essential nutrients, but they need a lot more of the three macro-elements, nitrogen(N), potassium(K) and phosphorus (P), than any of the other elements and a lot more nitrogen and potassium than phosphorus.

All three of these elements are mobile within the plant, and deficiencies will effect older leaves. If the older leaves are yellow, and growth is declining, you will usually get a rapid greening adding potassium nitrate (KNO3), it doesn't matter whether it is N or K that is deficient, you've added both.

Magnesium (Mg) is another deficiency that causes yellowing and effects older leaves, but you've been adding Mg, and plants need much less of it than they do N or K.

Iron (Fe) is needed in small amounts, but there are particular problems with keeping iron in solution. Iron isn't mobile within the plant and deficiencies effect young leaves. When you add iron you don't get an instant greening response, but new leaves that grow should be larger and greener.

If you have hard water iron deficiency is much more likely, and you may need to <"use a chelator"> that is better at high pH levels.

cheers Darrel

 

[jameson_uk]

One of the issues being colour-blind is that it is hard to distinguish between green, brown and yellow

I picked up some Tropica plant growth fertiliser which is meant to be macro and was the best the LFS had to offer.

Going to think about how I can add some man made floaters to provide a little shade whilst I source some more.

Today I have given the glass a good scrape, massively trimmed the moss and removed a fair amount of BBA from leaves. This has cleaned up most of the green algae on the glass and hair algae on the moss but there is still a fair amount of BBA (lots of tiny blobs on the edges of leaves (particularly the Anubias) which I will try and remove over the next week.

Given the high light levels, if I were to add some of the Tropica ferts might this actually make the algae worse?

Other than borrowing an SAE is there a better way of dealing with small patches of BBA? (Otos and Amanos have no interest in it)

 

[jameson_uk]

Also out of interest what sort of deficiency is this? The swords are several months old and the leaves look OK but around the crown looks quite week. This plant has already shed most it's leaves and grown new emersed ones. This does get a root tab right under it which I thought would sort out most of its requirements

 

[dw1305]

Hi all,

This plant has already shed most it's leaves and grown new emersed ones. This does get a root tab right under it which I thought would sort out most of its requirements

Unfortunately all the leaves with black bases will be shed.

Because the new plant looks healthy,and the plant has grown aerial leaves, I don't think it is a nutrient deficiency, I think the plant will carry on producing aerial leaves now, rather than submerged ones.

One of the issues being colour-blind is that it is hard to distinguish between green, brown and yellow

My dad is red-green colour blind, used to make picking raspberries interesting, he couldn't see any of the ripe ones.

However I see your Tadpole Snails in the photo and they are a good clue to when your Frogbit is nutrient deficient. When the snails start eating chunks out of the leaves (starting with the spongy aerenchyma tissue on the underside of the leaf) the leaf is unhealthy. They never eat the healthy leaves (other types of snail will).

cheers Darrel

 

[jameson_uk]

I never realised wild Amazon swords were typically emersed plants that live on the edges so cope with being submersed... will replacing this one with a younger plant mean it might actually develop submerged leaves? Will this one eventually die off if left? This one has developed quite a massive root structure.

Will order some more frogbit tomorrow and will see if the Tropica ferts make a difference. Just concerned that with the high light this will actually benefit the algae more than the plants. Should I be especially checking for yellowing? I can't tell from pictures in first post but I think they wife said they were green (from 20 feet whilst watching TV )

Looks like I need to check out the new Jewel LED lights which give out the same lumens as the T5s but have a controller which looks like you can drop the power. Main issue with this is that it costs ~£225 for the lights and controller.

 

[jameson_uk]

OK I trimmed a lot of the hair algae out of the moss and cleaned all the green stuff off the glass but there are still a few clumps of BBA (probably more than there were before).
I have added another five Amano Shrimp who have helped a bit but are not really touching the BBA.

So based on the above we think the Frogbit most likely died off due to a N or K deficiency? (the few plants that are left don't look as bad but don't look anywhere near as healthy as they once did)

I am assuming the root cause is too much (intense) light (which is not going to change in the short term) so If I do add some macro ferts are there any dangers?

• If dosing is intermittent will the level fluctuations actually cause more harm than good?
• Is adding these ferts with the high light but not CO2 asking for algae issues?

just realised that the Tropica stuff I bought is actually N & P with no mention of K but short term anything else will almost certainly be a pre-mix depending on what is available at LFS.

In short, what would you recommend to give the plants a bit of a boost and fend of the algae given that the lights are going to stay at 2x45W T5s and there will be no added CO2?

 

[Aqua360]

Please don't put any man made floaters in your tank