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GSA and plant deterioration - increase macro dose or supplement PO4?

Tom101

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Hi all

I've recently experienced a GSA outbreak and some plant health decline (pinholes, yellowing leaves) in my low tech set up (low light, no Co2).

During this period tank conditions haven't changed (flow, co2, water change schedule, feeding, lighting)

The only thing I can think of is that my root tabs may have "run out", so I've replaced these, however, the decline seems to have persisted

In this sort of situation, would you recommend dosing Phosphate separately to combat the GSA or just up overall ferts?

Any info appreciated.
 

MichaelJ

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Hi @Tom101 A couple of questions: How old is the tank? Can you post a Full Tank Shot (FTS). What are you dosing at the moment and how often (and how big is your tank) ?
I definitely have had very good experience eradicating GSA with increased PO4 dosing (~10ppm wk) - in combination with other measures, such as lower light intensity.

Cheers,
Michael
 

Tom101

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Hi @MichaelJ answers below:


Tank age

Tank is just over 1 year old, cycled from pre-existing filter media.
Prior to this GSA outbreak, it's had about 3 months of really nice plant growth and colour.
Unfortunately before that growth spurt it had a pretty bad BBA problem which was solved with improved flow.

Dosing
2ml Easy life carbo (daily)
1.5ml TNC complete (daily)
10ml Easy life Algaexit (weekly)
A few calcium cubes for the snails (weekly

Other info
Size is 70L
Lighting is Fluvial plant 3.0 - full spectrum @ 16% intensity for 8hrs a day
IMG-20220202-WA0003.jpeg

IMG-20220202-WA0005.jpeg

IMG-20220202-WA0007.jpeg
 

Hufsa

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I checked out your ferts, TNC Complete is pretty low on nitrate and phosphate.
I would get some more of that into the tank. Not sure if I would increase the dose of the Complete, the ratios are not EI so you'd end up with a lot of extra K and traces..
The plants will undoubtedly have gotten some of it from the soil previously, but the soil will start running low at some point, if it hasnt done it already
 

John q

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I think @Hufsa is correct in saying the phosphate levels are a bit low in comparison to nitrogen but I think you'd be ok increasing the dose of tnc complete a bit. Assuming you're adding 10.5ml a week it will give you this.
Screenshot_20220202-225145_Chrome.jpg


Which would equate to approx 10pppm of N03 & 0.9ppm of P04.
If you were to increase this by 50% to 2.25mls a day I think you'd be fine with the extra k that it would add, also the fe would still only be 0.18ppm p/w.

Best plan of action would be to try it and see if it helps.
 

MichaelJ

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Hi @Tom101 ,

Your tank look good! The GSA problem is nothing a bit of tweaking can't fix.

Well, I am going to raise John and @Hufta's good suggestions a bit and say make it a flat 3 ml daily of the TNC Complete. That will give you about 20 ppm of NO3 1.8 ppm of PO4 and 15 ppm of K all weekly - while your tank is not entirely dense, you do actually have quite a bit of plants there... Alternatively, or in addition, as I think the PO4 level might still be too low, based on my experience fighting GSA, is to dose some KH2PO4 in addition, say 0.5 g once per week at least for a month or so after the WC - which in addition to the TNC @ 3 ml /daily would give you 6 ppm of PO4 in total.

You may also want to dial down the light intensity a smidge and/or add some floating plants such as frogbit - they are excellent at providing shade and as a means to gauge your nutrient levels.

Cheers,
Michael
 
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Tom101

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Hi guys, thanks very much for your suggestions. I'll start upping the TNC as you've suggested. I'm hoping this will generate some improvement.

One thing I did notice, is that my new root tabs (add a week ago) don't contain any Nitrogen or Phosphate (I used the Seachem tabs). Is this a problem I should look to address?

@MichaelJ @Hufsa @John q
 

John q

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Is this a problem I should look to address?
Hi Tom, if you are dosing adequate nutrients in the water column then I don't think you need to be that worried about root tabs, the ones you've added will be fine.
Plants are perfectly capable of absorbing the things they need through their leaves, some people will suggest they do better when fed this way, others will suggest feeding through the roots is preferable. I don't honestly know which of the above methods works best but I do know plants can grow perfectly well without root tabs.

Hope that's of some help.
 

Tom101

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Hi guys

Update on the thread - it's been a month of dosing upping the daily TNC dose from 1.5ml to 3ml.

GSA is about the same, however, plants are looking a bit worse. Quite a few have now got a brown tinge or edge. Can't quite tell if it's diatoms or another deficiency.

Any thoughts?

@John q @MichaelJ @Hufsa
 

dw1305

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Hi all,
it's been a month of dosing upping the daily TNC dose from 1.5ml to 3ml. GSA is about the same however, plants are looking a bit worse. Quite a few have now got a brown tinge or edge. Can't quite tell if it's diatoms or another deficiency.
Could we have a full tank shot, and maybe a couple of close-ups of the worst effected plants?

cheers Darrel
 

John q

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Hiya mate. Its hard to tell from the pictures but are these issues predominantly in the central section of the tank or is it also affecting the plants far right and left, if its the former then we need to question the light intensity.

+1 for darrels suggestion of fts.
 

Tom101

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Hi both - shots attached. All plants affected (left, right, centre, multiple species). @dw1305 @John q
 

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MichaelJ

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Hiya mate. Its hard to tell from the pictures but are these issues predominantly in the central section of the tank or is it also affecting the plants far right and left, if its the former then we need to question the light intensity.

+1 for darrels suggestion of fts.

Agreed. A FTS and and possibly redo the 3rd shot in your original post so we can see the decline. I think (I might be wrong) that area is also the area that gets the highest light intensity. You want to dial that down for the time being. Other than that you have to look into flow as well - make sure you don't have any stale areas where nutrient distribution is low or absent.

If you want to experiment by upping the PO4 levels for a while (which have worked for me, and others, against GSA) you will have to dose that separately with Monopotassium phosphate (KH2PO4) or similar a compound. If your doing 50% WC weekly (35 L) you only need to add 0.25 g per week to reach 5 ppm - with the additional TNC complete you should be covered.

Cheers,
Michael
 

John q

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@Tom101 I'm struggling a bit to get my head around your light settings. My gut instinct is to suggest lowering the intensity a bit, you seem to be getting some growth like side shoots forming and good colouration in the red stems, which suggests there is enough light. However, if I'm right in thinking you have the 22w fluval fixture and this is set at 16%(?) This would equate to your tank only getting 3.52w. The picture looks like it's getting more than this.

Either way like MichaelJ says double check you've adequate flow in the tank and add a separate source of Po4, Seachem phosphorus will suffice if you don't want to go down the dry salt route. (Increasing this also worked for me in the past against gsa.)

The brown edging is indeed diatoms and should rub off the leaves, just be sure to do a water change after you've cleaned it off the leaves.
 

MichaelJ

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What John says.... It can be hard to judge from a picture, but the light looks quite intense to me as well - nothing like the 16% setting on a Fluvial plant 3.0 (which I believe is 32w) which is quite low.

Cheers,
Michael
 

Tom101

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Thanks for the replies. I'll grab some extra PO4 and crack on with that.

I've double checked my light spec/settings and it is indeed the 32W version at 16% (8hrs). I think the angle of the picture is making it look a bit brighter than it is.

In the past I have experimented dropping below 16% but found that plant health deteriorated (all other factors unchanged).
 

John q

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I've double checked my light spec/settings and it is indeed the 32W version at 16%
Hi Tom,
My bad, assumed it was the smaller version. Sorry for all the questions but I'm just trying to guesstimate the amount of par you have at the bottom of this tank.
If you'd be so kind as to humor me and let me know the distance from the light to the top of the substrate I'd be ever so grateful.

Ta.
 
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Tom101

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Hi @John q no problem at all - I appreciate the help!

Distance from the bottom of the light housing to the top of the substrate is approx 31.5cm.
 

dw1305

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Hi all,
I've double checked my light spec/settings and it is indeed the 32W version at 16% (8hrs). I think the angle of the picture is making it look a bit brighter than it is.

In the past I have experimented dropping below 16% but found that plant health deteriorated (all other factors unchanged).
Turn up the <"intensity a bit"> and that will at least take low light away from our possible causes of poor plant growth.

If the plants really do look pale? You could try a bit more magnesium (Mg), you can buy it easily as "Epsom Salts" (MgSO4.7H20) for baths etc and that is 10% Mg.

If the new leaves are palest? It may be an <"iron (Fe) availability issue">. For iron deficiency you are looking for this effect (below). I like a floating plant because they are adapted to strong light and aren't CO2 limited. I particularly recommend Amazon Frogbit (Limnobium laevigatum) because it has a <"nice green leaf"> and will still grow in very nutrient poor, acid water.

dad12186cb152cccee11028dc11c34f4-jpg.135357

All the other nutrients that cause pale leaves (nitrogen (N), potassium (K) & magnesium) are mobile within the plant and <"it is the older leaves that are chlorotic">.
This is what Amazon Frogbit looks like, if you <"feed it plenty">.

sigrjybcq-width-3264-height-2448-cropmode-none-jpg.jpg
cheers Darrel
 
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